Simple Probe

Know Your 5 Critical Numbers


You're Far More Liable to Die from Dangerous Cholesterol Levels Than Dangerous Airspeeds

By Glenn R. Stoutt, Jr., M.D, Senior FAA Aviation Medical Examiner

Numbers graphic

Pilots know all the critical airspeed numbers for their aircraft; but, unfortunately, most of them do not know the few (only five) critical numbers for blood fats (lipids). Cholesterol is the one most people hear about. But, you are far more liable to die from dangerous cholesterol levels than dangerous airspeeds. Here is all you need to know about blood lipids:

Cholesterol is a substance found in foods of animal origin, such as beef, lamb, cheese, eggs, poultry, and dairy products. Everyone has and needs cholesterol for such things as building cells, making hormones, and making vitamin D. Young children especially need it for development of the nervous system.

Problems begin only when the level of cholesterol becomes too high. Cholesterol—in the form of the "bad" low density lipoprotein cholesterol or LDL—can become deposited in the walls of arteries, narrowing them — "clogged arteries"—and reducing or even shutting off the blood supply to vital organs and tissues. Think of it as "rusting your pipes." If the artery is one of the coronary (heart) arteries, insufficient blood supply to the heart muscle may result in a heart attack.

Elevations in cholesterol are directly related to the risk of having a heart attack. Good news: For every 1% that high levels of cholesterol are reduced, your risk of heart disease is lowered by 2%.

HDL (high-density lipoprotein) cholesterol is called the "good" cholesterol because it acts as a scavenger and removes the bad cholesterol from the blood. Think of it as a "Pac Man" if you are old enough to remember this computer game where the Pac Man gobbled up his victims.

Really, all you need to do initially is to get your total cholesterol (TC), HDL cholesterol, and triglycerides measured. The LDL is then calculated from these numbers. Triglycerides are the

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chemical form in which most fats exist in food as well as in the body. High levels are associated with heart disease.

The American Heart Association would like everyone ideally to have a total cholesterol of about 160 mg/dl and an HDL of over 35 mg/dl (mg/dl means milligrams per deciliter). The higher the HDL the better. I would like to see it over 50. A high HDL is great news.

Here are the important numbers you should know:

Total Blood Cholesterol

Less than 200 mg/dl = desirable blood cholesterol200-239 mg/dl = borderline-high blood cholesterol240 mg/dl or more = high blood cholesterol

TriglyceridesUnder 200 mg/dl

LDL cholesterolUnder 130 mg/dl

HDL cholesterolOver 35 mg/dl

Total cholesterol to HDL cholesterol ratioNot over 5 to 1; ideally, 3.5 to 1

Your body gets cholesterol in one of two ways: in your diet or from cholesterol manufactured by your liver. Your liver makes about 80%of your cholesterol and heredity plays a big role in how much it produces and how much is removed from your bloodstream. Even if you eat no cholesterol or saturated fat, your liver will still make as much cholesterol as your body needs, often way too much if you are genetically predisposed.

Dietary cholesterol (eggs, liver, shrimp) plays a significant part, but dietary fat (especially saturated fat) is the bigger culprit. (Fortunately, there is no cholesterol in plant foods like fruits, vegetables, and cereals.) Saturated fat is the "building block" of cholesterol. If you want to look at saturated fat, just look at the marbling on red meat.

The American Heart Association recommends a maximum of 30%of our daily calories from fat. I would like to see it at about 20%. Dietary fat comes in three varieties— limit each to a maximum of 10%of your diet.

Saturated fat: Mostly from animal sources such as meats (lamb, pork, beef) and dairy foods such as cheese, whole milk, and ice cream. A few vegetable products (coconut oil, palm oil, palm kernel oil, and vegetable shortening) are high in saturated fats. All are bad news for your arteries.

Polyunsaturated fat: Cold-water fish oils (tuna, cod, halibut) and vegetable oils such as safflower, corn, sunflower seed, and soybean. Much better for you, and will actually lower your cholesterol, but will still put on the pounds.



Monounsaturated fats: Olive oil and peanut oil are good examples. Olive oil (plus a modest amount of red wine) may be a reason the Mediterranean people have fewer heart attacks. Monounsaturates are the best of all the dietary fats.

What about trans fats? Newspaper and magazine articles have been inundating us with information about these "bad" fats. Essentially, they are polyunsaturated fats that have been artificially hydrogenated by food manufacturers and processors. This "hardening" also makes them almost as bad for us as saturated fats. Essentially, these hardened fats harden your arteries.

These trans fats were designed for two purposes. The first is that they extend the shelf life of the products by reducing oxidative spoilage. But, the main reason is that they make the product firm. This is desirable for stick margarine, cookies, doughnuts, pastries, and dessert buns. Right up there with the hot dog as nutritional poison is the glazed doughnut (a favorite with pilots and police officers)—loaded with trans fat. This doughnut comes out of the oven dripping oil and is so floppy it has to be eaten with two hands. But when it cools to room temperature, it is firm and dry.

Stick margarine is almost as bad as butter. Soft (tub) margarine—used sparingly—is a better choice. Best of all is no-fat margarine. Unfortunately, about five to ten percent of our processed foods, mostly bakery goods, contain these trans fats, and the labels at this date do not tell you this.

With diet and exercise you can reduce your cholesterol level at least by 20%, not much more because of the large amount of cholesterol the liver is genetically programmed to make.

If you cannot get your cholesterol below 240, medication may be indicated, and it is usually effective. Try to get maximum results from diet and regular, vigorous exercise before seeking medication. Remember also that soluble fiber, especially oat bran, reduces the absorption of cholesterol. A researcher at the University of Kentucky thinks that several helpings of oatmeal a day may be almost as good as medication to reduce your cholesterol. (Even if he's wrong, oatmeal is good for you.)

Conclusion: Get a lipid profile. Know what the numbers mean, and if any are out of line consult your physician. In any case, exercise, a low fat diet, and maintaining ideal body weight may not only be life prolonging but lifesaving. (Keep checking your airspeed numbers too.)

Yours for good health and safe flying,

Glenn Stoutt

Factoids

❍ Only 0.7% of all airmen are denied certification. This is reduced to 0.1% when airmen follow up and provide the requested information. Far better than the figures for life-insurance applicants.

❍ We need about 25-30 grams of fiber a day. For example, one serving of All-Bran Extra Fiber



provides half of your daily needs. All-Bran tastes like shredded cardboard, so add another flavored cereal or some fruit to mask the taste. Alternate with oatmeal for breakfast. Go slowly when adding fiber to your diet. Add a few grams a day to your diet to avoid bloating and intestinal gas.

❍ About 70% of health problems are caused by faulty lifestyle— smoking, obesity, drug and alcohol abuse, fatty-salty-sugary diet, and lack of exercise being prime examples.

Dr. Glenn R. Stoutt, Jr., is a partner is the Springs Pediatrics and Aviation Medicine clinic, Louisville, Ky., and has been an active AME for 37 years. No longer an active pilot, he once held a commercial pilot's license with instrument, multiengine, and CFI ratings.


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Aviation Search Engine

Alcohol and Flying: A Deadly Combination

Alcoholic beverages used by many to "unwind" or relax, act as a social "ice-breaker," a way to alter one's mood by decreasing inhibitions. Alcohol consumption is widely accepted, often providing the cornerstone of social gatherings and celebrations. Along with cigarettes, many adolescents associate the use of alcohol as a rite of passage into adulthood. While its use is prevalent and acceptable in our society, it should not come as a surprise that problems arise in the use of alcohol and the performance of safety-related activities, such as driving an automobile or flying an aircraft. These problems are made worse by the common belief that accidents happen "to other people, but not to me."

There is a tendency to forget that flying an aircraft is a highly demanding cognitive and psychomotor task that takes place in an inhospitable environment where pilots are exposed to various sources of stress.

Hard facts about alcohol

● It's a sedative, hypnotic, and addicting drug. ● Alcohol quickly impairs judgment and leads to behavior that can easily

contribute to, or cause accidents.

The erratic effects of alcohol

Alcohol is rapidly absorbed from the stomach and small intestine, and transported by the blood throughout the body. Its toxic effects vary considerably from person to person, and are influenced by variables such as gender, body weight, rate of consumption (time), and total amount consumed.

The average, healthy person eliminates pure alcohol at a fairly constant rate - about one-third to one-half oz. of pure alcohol per hour, which is equivalent to the amount of pure alcohol contained in any of the popular drinks listed in Table 1. (note: tables not included in this text.) This rate of elimination of alcohol is relatively constant, regardless of the total amount of alcohol consumed. In other words, whether a person consumes a few or many drinks, the rate of elimination of alcohol from the body is essentially the same. Therefore, the more alcohol an individual consumes, the longer it takes his/her body to get rid of it.

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Even after complete elimination of all of the alcohol in the body, there are undesirable effects-hangover-that can last 48 to 72 hours following the last drink. The majority of adverse effects produced by alcohol relate to the brain, the eyes, and the inner ear-three crucial organs to a pilot. Brain effects include impaired reaction time, reasoning, judgment, and memory. Alcohol decreases the ability of the brain to make use of oxygen. This adverse effect can be magnified as a result of simultaneous exposure to altitude, characterized by a decreased partial pressure of oxygen. Visual symptoms include eye muscle imbalance, which leads to double vision and difficulty focusing. Inner ear effects include dizziness, and decreased hearing perception. If such other variables are added as sleep deprivation, fatigue, medication use, altitude hypoxia, or flying at night or in bad weather, the negative effects are significantly magnified.

Studies of how alcohol affects pilot performance

Pilots have shown impairment in their ability to fly an ILS approach or to fly IFR, and even to perform routine VFR flight tasks while under the influence of alcohol, regardless of individual flying experience. The number of serious errors committed by pilots dramatically increases at or above concentrations of 0.04% blood alcohol. This is not to say that problems don't occur below this value. Some studies have shown decrements in pilot performance with blood alcohol concentrations as low as the 0.025%.

Studies of fatal accidents

This information is based on the analysis of blood and tissue samples from pilots involved in fatal aviation accidents.

Hangovers are dangerous

A hangover effect, produced by alcoholic beverages after the acute intoxication has worn off, may be just as dangerous as the intoxication itself. Symptoms commonly associated with a hangover are headache, dizziness, dry mouth, stuffy nose, fatigue, upset stomach, irritability, impaired judgment, and increased sensitivity to bright light. A pilot with these symptoms would certainly not be fit to safely operate an aircraft. In addition, such a pilot could readily be perceived as being "under the influence of alcohol."

You are in control

Flying, while fun and exciting, is a precise, demanding, and unforgiving endeavor. Any factor that impairs the pilot's ability to perform the required tasks during the operation of an aircraft is an invitation for disaster. The use of alcohol is a significant self-imposed stress factor that should be eliminated from the cockpit. The ability to do so is strictly within the pilot's control. Federal Aviation Regulation (FAR) 91.17. The use of alcohol and drugs by pilots is regulated by FAR 91.17. Among other provisions, this regulation states that no person may operate or attempt to operate an aircraft:

● within 8 hours of having consumed alcohol● while under the influence of alcohol● with a blood alcohol content of 0.04% or greater● while using any drug that adversely affects safety


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Keep in mind that regulations alone are no guarantee that problems won't occur. It is far more important for pilots to understand the negative effects of alcohol and its deadly impact on flight safety.

General Recommendations

1. As a minimum, adhere to all the guidelines of FAR 91.17: 8 hours from "bottle to throttle" do not fly while under the influence of alcohol do not fly while using any drug that may adversely affect safety

2. A more conservative approach is to wait 24 hours from the last use of alcohol before flying. This is especially true if intoxication occurred or if you plan to fly IFR. Cold showers, drinking black coffee, or breathing 100% oxygen cannot speed up the elimination of alcohol from the body.

3. Consider the effects of a hangover. Eight hours from "bottle to throttle" does not mean you are in the best physical condition to fly, or that your blood alcohol concentration is below the legal limits.

4. Recognize the hazards of combining alcohol consumption and flying.

5. Use good judgment. Your life and the lives of your passengers are at risk if you drink and fly.

Ideally, total avoidance of alcohol should be a key element observed by every pilot in planning or accomplishing a flight. Alcohol avoidance is as critical as developing a flight plan, a good preflight inspection, obeying ATC procedures, and avoiding severe weather.

QUIZ

To test your knowledge of alcohol, fill in the blanks.

1. Over ____ % of American adults consume alcohol.

2. Per capita consumption of alcohol in the U.S. is about ____ gallons per year.

3. Alcoholic beverages are marketed in a variety of forms, with ____ and ____ being the most liked.

4. Blood alcohol levels above ____ % are considered "under the influence" in most states for motor vehicle operation.

5. Different alcoholic beverages have different concentrations of alcohol; however, their total alcohol content can be ______ _______. For example, a pint of beer contains as much alcohol as a ____ ounce glass of _______ ________ . Therefore, the notion that drinking low-concentration alcoholic beverages is safer than drinking hard liquor is erroneous.

6. The total alcohol content of any alcoholic beverage can be easily calculated using the following formula: "Proof" divided by ____ is equal to percent pure alcohol.

ANSWERS TO QUIZ

ALCOHOL USE IN AMERICA

1. Over 50 % of all American adults consume alcohol.

2. Per capita consumption is about 25 gallons per year.

3. Alcoholic beverages are marketed in a variety of forms, with wine and beer being the most liked.

4. Blood alcohol levels above 0.08 to 0.10 % (80-100 mg of alcohol per 100 mL of blood) are considered "under the influence" in most states for motor vehicle operation.


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5. Different alcoholic beverages have different concentrations of alcohol; however, their total alcohol content can be the same. For example, a pint of beer contains as much alcohol as a 5 H ounce glass of table wine. Therefore, the notion that drinking low-concentration alcoholic beverages is safer than drinking hard liquor is erroneous.

6. The total alcohol content of any alcoholic beverage can be easily calculated using the following formula: "Proof" divided by 2 = percent pure alcohol.

by Dr's. Guillermo Salazar and Melchor Antuñano


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A Flight In The Chamber: An Encounter With Hypoxia

A pilot discovers, close up, an insidious killer.

We were at 35,000 feet, and student Number 5 had been without his oxygen mask for less than a minute. Number 5 was in trouble, but he didn't know it. The instructor tried to get student Number 5's attention. "Gang load your regulator, Number 5. Put your oxygen mask on. Number 5, gang load your regulator and put your oxygen mask to your face." Student Number 5's eyes were open, but he wasn't responding. His skin was the color of someone who had been embalmed. His hands shook, and he could no longer hold on to anything. He was gasping convulsively and was unable to speak. The instructor gang loaded Number 5's regulator (all regulator switches to the up position in one motion) and placed the oxygen mask to his face. One hundred percent

under high pressure revived him, although he remained shaky for several more minutes. Student Number 5 had little recollection of what he had just experienced. We descended to 30,000 feet, and student Number 13 was instructed to remove his oxygen mask. He was fine for a minute or so but complained of feeling very tried. Suddenly, he slumped in his seat. Only after he heard the instructor's voice coming

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through the headphones was he able to rouse himself enough to get his oxygen mask back on without assistance. After a day and a half of classroom instruction on various topics related to aerospace physiology at Fairchild Air Force Base (AFB), Spokane, Washington, our training culminated in actually experiencing how hypoxia can affect not only those of us who

fly but those who fly with us. Now, after watching demonstrations, it was our turn. The chamber pressure was adjusted to 25,000 feet, and the rest of us (10 Air Force personnel and five-civilian employees from the Boeing Company) were instructed to turn off our regulators and remove our oxygen masks. We were given work sheets with math and word problems and a puzzle maze to solve.

As we completed our work sheets, we were to record how we were feeling. The purpose was not to see how long we could last without pressurized oxygen but to be able to identify two or three symptoms of hypoxia in ourselves and then take appropriate action by gang loading our regulators and replacing our oxygen masks.

For some students in our class, the symptoms of hypoxia were quite dramatic - hot and cold flashes, tingling in the hands and feet, blue fingernails, nausea, headache. My symptoms were subtle: a slight headache, a slight sensation of just not feeling well, a little tingling in the feet and legs-symptoms I would have not recognized without this training.

As pilots recall from ground school, the air we breathe is made up of 21 percent oxygen, 78 percent nitrogen and one percent other gases. As altitude increases, this mixture of gases remains the same, but atmospheric pressure decreases. Our lungs need a certain amount of atmospheric pressure for oxygen to be absorbed, and at altitudes above 10,000 feet, the pressure is not sufficient for this to take place, depriving the brain and other tissues of adequate oxygen, which leads to the condition known as hypoxia.

Each person's tolerance and reaction to hypoxia is different, but the end result is the same. As the amount of oxygen to the tissues decreases, you will remain conscious for a short time but will become less and less functional. Unless you correct the situation by breathing pressurized oxygen, if it is available, or by descending to a lower altitude, the hypoxia will lead to unconsciousness and eventually, death.

Depending on altitude, once you start becoming hypoxic, you have only a limited amount of time to correct the situation before useful function is lost. This period is referred to as "Time of Useful Consciousness (TUC). As you can see by the chart above, you may have several minutes to recognize


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your symptoms and take corrective action-or you may have only seconds.

In a rapid decompression situation such as might be experienced during a catastrophic event on an airliner, the times of useful consciousness, as shown on the chart, are cut in half. So, for instance, if you were to experience rapid decompression at 40,000 feet, rather than having 15 to 20 seconds to react, you would have only from 7.5 to 10 seconds of useful consciousness. This is why you are always briefed to get your own oxygen mask on before taking care of your children. If you help someone else first, you may not have time to help yourself.

Because the body functions quite nicely from sea level to 10,000 feet, pilots are not required to have pressurized oxygen available for flights at this altitude or below. However, some tissues, like those of the eye, are very susceptible to any decrease in available oxygen-just how susceptible would become graphically apparent during the night vision portion of our training.

After spending some time at ground level with lights off and oxygen masks removed, we went up to 10,000 feet. After a short time at this altitude, we were each handed a large color wheel. We were able to see the various segments on the color wheel, but the colors themselves were nearly indistinguishable, appearing only as shades of gray.

Upon command, we donned our oxygen masks. Two or three breaths of oxygen worked like magic! The colors became vividly apparent along with detail many of us had previously been unable to see. It was an impressive demonstration of how flight at 10,000 feet adversely affected our night vision even after a short amount of time.

One of the most dangerous aspects of hypoxia is that the onset of symptoms may be very subtle and may not cause discomfort. For some individuals, the symptoms can even be pleasant. If the onset of hypoxia is slow, the symptoms may be well developed before you recognize them, and by then, it may be too late to help yourself.

One of the main reasons pilots attend aerospace physiology training is to be able to experience their own symptoms of hypoxia and to witness the symptoms in others in the controlled environment of an altitude chamber.

CAMI's Aeromedical Education Division offers a 1-day aviation physiology course for FAA flight crews, civil aviation pilots, and FAA aviation medical examiners (AMEs). In addition to the basic academic contents, this course offers practical demonstrations of rapid decompression (8 to 18K feet) and hypoxia (25K feet) in a hypobaric chamber. This course is in Oklahoma City, Oklahoma and is free. To schedule you must call (405) 954-7767 / 4837. Class starts at 8 AM and is finished around 3:30 PM.

A similar aviation physiology course is offered to civil aviation pilots at USAF physiological training units across the U.S. under the USAF/FAA Physiological Training Agreement. This program has been very successful and is a good example of how government organizations can collaborate to promote safety in civil aviation. To be scheduled you must call (405) 954-6209/4837. The cost is $35 dollars.


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To participate in the altitude chamber you must be 18 years of age or older, no beards, and have a current class 3 or better flight physical.

CAMI's Aeromedical Education Division also offers a survival course for general aviation pilots at Oklahoma City, Oklahoma. This is a 8-hour introductory course that will provide the basic knowledge and skills for coping with various common survival scenarios. This course will teach students how to easily assemble and use a personal survival kit. The course is free and to schedule call (405) 954-6207/4837.

By Carol Colleen


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Decompression Sickness in a Private Pilot

Civil aviation can result in some unique medical problems that are unfamiliar to most physicians. One such problem, decompression sickness, is not mentioned in most medical texts, and is not included in most medical school instruction. If not promptly recognized and treated, decompression sickness can result in permanent disability or death. I report a case of altitude-induced decompression sickness after a flight in an unpressurized aircraft.

DECOMPRESSION SICKNESS (DCS) is an illness caused by a reduction in ambient pressure, resulting in the formation of bubbles of inert gas (usually nitrogen) within body tissues. DCS can occur as a result of high altitude exposure

(in an altitude chamber or in an unpressurized aircraft), work in pressurized tunnels and caissons, and compressed air (scuba) diving. The risk of DCS is increased when a compressed air dive is immediately followed by exposure to reduced atmospheric pressure, such as a flight in an aircraft. The risk is further increased when a flight is accomplished after several deep

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dives in succession without adequate time for reequilibration. The incidence of DCS among private pilots is unknown. Many cases of DCS probably go unrecognized, with spontaneous recovery. Even when the illness is recognized and treated, there is no requirement for reporting DCS by either the pilot or treating physician.

Case Report

A healthy, experienced, 59-year-old private pilot planned a cross-country flight from Missouri to California. He had an uneventful ascent to an altitude of 28,000 feet above mean sea level (MSL) in the unpressurized airplane, and began using supplemental oxygen after passing 12,000 feet MSL, as required by federal aviation regulations. After 1 hour at his cruising altitude, the pilot noticed the onset of weakness and paresthesias of the right arm. A few minutes later, he felt extreme fatigue and chest tightness associated with a dry cough. These symptoms progressively worsened, and were soon accompanied by left arm weakness and paresthesias. He had no dyspnea, diaphoresis, visual or auditory symptoms, or alteration in consciousness. There was no previous history of similar symptoms or of pulmonary, cardiac, or neurologic problems. The pilot remained on oxygen by mask, and began to slowly descend, landing his aircraft in New Mexico. He remained ill, and was immediately transported to a local hospital.

Upon arrival at the emergency department, he was diaphoretic and ashen. He continued to complain of weakness and paresthesias of both arms, but more severe on the right. Supine blood pressure was 115/88 mm Hg, supine pulse rate 98/min, and respiratory rate 20/min. When the patient was standing, blood pressure dropped to 75/41 mm Hg, with pulse unchanged. There was no skin rash, mottling, or edema. Head and neck examination was unremarkable. Cardiac rate and rhythm were regular, with normal heart sounds. Mild crackles were heard at both lung bases. Abdominal examination was unremarkable. On neurologic examination, the patient was alert and fully oriented. All cranial nerves were normal. Examination of the right upper extremity revealed severe flexor weakness at the elbow and wrist, severe weakness of grip strength, numbness of the forearm, and severely impaired fine motor control. The left upper extremity also showed flexor weakness and decreased grip strength, but not as severe as on the right. Sensation was normal. Strength and sensation in the lower extremities was normal. Gait was not tested because of orthostasis.

Chest x-ray films showed mild increase in interstitial markings. Electrocardiogram showed a 1 mm elevation in ST segments in leads V2 and V5. Perfusion scans of the lungs were normal. Arterial blood gas values, with the patient breathing room air, were pH 7.40, P02 111 mm Hg, Pco2 33.4 mm


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Hg, and oxygen saturation 96%. Serum potassium level was 3.3 mg/dL; remaining electrolyte values were normal.

A diagnosis of altitude-induced decompression sickness was made. The patient was maintained on 100% oxygen by mask, and transported by pressurized aircraft to the Hyperbaric Medicine Division at Brooks Air Force Base in Texas, arriving approximately 12 hours after landing his aircraft. Upon arrival, findings on physical examination were unchanged. The patient was immediately placed in the hyperbaric chamber for compression therapy. Following a standard hyperbaric treatment, some neurologic improvement was noted, although the deficits of the right upper extremity persisted. Over the next 4 days, the patient received an additional seven treatments. The first 5 of these treatments produced improvement. The decision to terminate treatments was made when there was no further improvement after the final two treatments. At the conclusion of hyperbaric therapy, there was persistent weakness of the right shoulder and weakness of the intrinsic muscles of the right hand. At follow-up 1 year later, the patient had complete recovery in the muscles of the right hand, but continued to have mild weakness in the right shoulder.

DISCUSSION

One of the most serious physiologic problems associated with aviation is decompression sickness (DCS). As early as 1917, Henderson predicted the possibility of DCS in aviators flying at more than 20,000 feet. DCS occurs when a person is subjected to a reduction in ambient pressure. During decompression, body tissues become supersaturated with inert gas (nitrogen). Excess nitrogen in the tissues diffuses into the blood, is carried to the lungs, and eliminated in expired air. The amount of nitrogen remaining in body tissues is directly proportional to the nitrogen partial pressure around the person. If the amount of dissolved nitrogen exceeds some threshold, the critical supersaturation point, some of the nitrogen comes out of solution in the form of bubbles. These bubbles are the basis for the development of symptoms of DCS. The etiology, pathophysiology, epidemiology, and clinical manifestations of altitude decompression sickness were described by Fryer in his 1969 monograph.

Decompression sickness is rare for unpressurized flights that do not exceed an altitude of 29,000 feet. There has been a recent proliferation of unpressurized private aircraft that can exceed altitudes of 24,000 feet; Beech, Piper, Cessna, and Mooney all currently manufacture such aircraft.

The clinical manifestations of DCS are variable, with many of the symptoms being protean. The varied nature of DCS has led Behnke to compare it with the spirochete as the "great imitator." The many signs and symptoms of DCS can occur in any combination, which can make the diagnosis difficult. Wirjosemito, et al. noted that the clinical manifestations of serious altitude DCS include, in descending order of frequency, joint and limb pain, headache, visual disturbances, extremity paresthesia, mental confusion, extremity weakness, fatigue, cerebellar signs, pulmonary manifestations (chokes), and extremity numbness.

Several factors may predispose a pilot to the development of DCS. Risk of DCS increases as the altitude of exposure increases, as the rate of ascent increases, and as the duration of exposure lengthens. Personal factors that increase risk of DCS include age (susceptibility increases with age), body build (obese individuals are at greater risk), and recent joint injury.


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Initial management of decompression sickness consists of hydration, delivery of 100% oxygen, and transfer to a compression chamber for the compression therapy. Serious cases of DCS may require other supportive measures (e.g., intubation and pressor agents).

Compression (hyperbaric) therapy is the definitive treatment of DCS. The longer the delay in treatment, the poorer the outcome. Rudge and Shafer, in a study of altitude-induced DCS cases treated by the United States Air Force, noted that patients treated rapidly with compression therapy recovered faster than patients whose treatment was delayed.

The Divers Alert Network, located at Duke University, provides 24-hour information regarding the diagnosis and management of DCS, and can supply up-to-date information on compression chamber locations. The number for this service is (919) 684-8111.

A requirement for the treatment of any disease process is a full understanding of the clinical picture of the disease. This can be especially difficult in DCS, with its broad spectrum of presenting signs and symptoms. In many cases, the patient must be relied on to present an accurate and truthful description of the problem. Pilots should be educated to promptly seek medical treatment when problems develop during or after flying. Health care providers must be able to identify individuals at risk for DCS, to recognize the bewildering array of possible presentations, and to initiate prompt treatment. When doubt exists, consultation with a trained flight surgeon or hyperbaric physician should be obtained.

This article was reprinted by permission from the SOUTHERN MEDICAL JOURNAL, Volume 38, No. 2, pages 228-9, February 1995. We thank Dr. Rudge and the Southern Medical Journal for allowing us to present this information about decompression sickness. Space and deadlines combined to cause us not include the references. If you would like to receive the references, please write to: FAA Civil Aeromedical Institute, Aeromedical Education Division, AAM-400, P.O. Box 25082, Oklahoma City, OK 73125.

By COL FREDERICK W. RUDGE. MC, USAF, SAN ANTONIO, TEXAS


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Information Regarding Aeromedical Certification of Individuals with Insulin-Treated Diabetes Mellitus Diabetic Pilot "Overjoyed" to Fly Again

The FAA is now considering certification, under the Special Issuance provisions of the Federal Aviation Regulations, of some individuals with insulin-treated diabetes mellitus (ITDM). The following restrictions apply:

1. ITDM individuals may be issued only a third-class airman medical certificate.

2. ITDM individuals may exercise only the privileges of a student, recreational, or private pilot certificate.

3. ITDM individuals are prohibited from operating an aircraft as a required crewmember on any flight outside the airspace of the United States of America.

4. ITDM individuals are required to be in compliance with the monitoring requirements of the protocol outlined below while exercising the privileges of a third-class airman medical certificate.

In order to be considered for aeromedical certification, an individual with ITDM must meet the following criteria.

For initial certification:

A. Individuals with ITDM who have no otherwise disqualifying conditions, especially significant diabetes-related complications such as arteriosclerotic coronary or cerebral disease, retinal disease, or chronic renal failure, will be evaluated for special issuance of a third-class medical certificate if they have had no recurrent (two or more) hypoglycemic reactions resulting in a loss of consciousness or seizure; no recurrent hypoglycemic reactions requiring intervention by another party; and no recurrent hypoglycemic reactions resulting in impaired cognitive function which occurred without warning symptoms within the past 5 years. A period of 1 year of demonstrated stability is required following the first episode of hypoglycemia.

B. In order to provide an adequate basis for an individual medical determination, the person with ITDM seeking special issuance of a medical certificate must submit the following:

1. Copies of all medical records concerning the individual's diabetes diagnosis and disease history and copies of all hospital records, if admitted for any diabetes-related cause, including accidents and injuries;

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2. Copies of complete reports of any incidents or accidents, particularly involving moving vehicles, whether or not the event resulted in injury or property damage, if due in part or totally to diabetes;

3. Results of a complete medical evaluation by an endocrinologist or other diabetes specialist physician acceptable to the Federal Air Surgeon (hereafter referred to as "specialist"). This report should detail the individual's complete medical history and current medical condition. The report must include a general physical examination and, at a minimum, the following information:

(a) Two measurements of glycated hemoglobin (total A1 or A1C concentration and the laboratory reference normal range), the first at least 90 days prior to the current measurement;

(b) A detailed report of the individual's insulin dosages (including types) and diet utilized for glucose control;

(c) Appropriate examinations and tests to detect any peripheral neuropathy or circulatory insufficiency of the extremities and any other tests deemed necessary by the treating specialist or that are clinically indicated; and

(d) Confirmation by an ophthalmologist of the absence of clinically significant eye disease. The eye examination should assess, at a minimum, visual acuity, ocular tension, and presence of lenticular opacities, if any, and include a careful examination of the retina for evidence of any diabetic retinopathy or macular edema. The presence of microaneurysms, exudates, or other findings of background retinopathy, by themselves, are not sufficient grounds for disqualification unless it prevents the subject from meeting visual standards. However, individuals with active proliferative retinopathy or vitreous hemorrhages will not be considered for special issuance of a medical certificate until the condition has stabilized and this has been confirmed by an ophthalmologist.

4. Verification by a specialist that the individual has been educated in diabetes and its control and has been thoroughly informed of and understands the monitoring and management procedures for the condition and the actions that should be followed if complications of diabetes, including hypoglycemia, should arise. Such verification should also contain the specialist's evaluation as to whether the individual has the ability and willingness to properly monitor and manage his or her diabetes and whether diabetes will adversely affect his or her ability to safely control an aircraft. The presence or absence of recurrent severe hypoglycemia and hypoglycemia unawareness should be noted. (See A. above.)

5. The individual must authorize his/her treating physician(s) to provide any available information regarding his/her diabetes to the FAA upon request.

C. The ITDM individual applying for special issuance of a medical certificate should have been receiving appropriate insulin treatment for at least 6 months prior to submitting a request for special issuance of a medical certificate.

D. Special demonstration flight test. If the Federal Air Surgeon determines that there is need for an


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ITDM applicant to demonstrate his or her ability to comply with the medical protocol, the Federal Air Surgeon, under the provisions of 14 CFR § 67.401 (Federal Aviation Regulations), may require a special medical examination and/or demonstration flight test prior to a determination of the applicant's eligibility for special issuance of a medical certificate.

E. The individual must agree to immediately report any adverse changes in their medical condition to the FAA.

During flight:

A. Individuals with ITDM shall maintain appropriate medical supplies for glucose management at all times while preparing for flight and while acting as pilot-in-command (or other flightcrew member). At a minimum, such supplies shall include:

1. an FAA-acceptable whole blood digital glucose monitor with memory;

2. supplies needed to obtain adequate blood samples and to measure whole blood glucose; and

3. an amount of rapidly absorbable glucose, in 10 gram (gm) portions, appropriate to the potential duration of the flight.

B. All disposable supplies listed above must be within their expiration dates.

C. The individual with ITDM, acting as pilot-in-command or other flightcrew member, shall establish and document a blood glucose concentration equal to or greater than 100 milligrams/deciliter (mg/dl) but not greater than 300 mg/dl within 1/2 hour prior to takeoff. During flight, the individual with ITDM shall monitor his or her blood glucose concentration at hourly intervals and within 1/2 hour prior to landing. If a blood glucose concentration range of 100-300 mg/dl is not maintained, the following action shall be taken:

1. Prior to flight.

The individual with ITDM shall test and record his or her blood glucose concentration within 1/2 hour prior to takeoff. If blood glucose measures less than 100 mg/dl, the individual shall ingest an appropriate 10 gm glucose snack (minimum 10 gm) and recheck and document blood glucose concentration after ½ hour. This process shall be repeated until blood glucose concentration is in the 100-300 mg/dl range. If blood glucose concentration measures greater than 300 mg/dl, the individual shall follow his or her regimen of blood glucose control, as provided to the FAA by his or her attending physician, until the measurement of blood glucose concentration permits adherence to this protocol.

2. During flight.

(a) One hour into the flight, at each successive hour of flight, and within 1/2 hour prior to landing, the individual shall measure and document his or her blood glucose concentration. Listed below are


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blood glucose concentration ranges and the actions to be taken when they occur during flight:

(1) Less than 100 mg/dl: The individual shall ingest a 20 gm glucose snack and recheck and document his or her blood glucose concentration after 1 hour.

(2) 100-300 mg/dl: The individual may continue his or her flight as planned.

(3) Greater than 300 mg/dl: The individual shall land as soon as practicable at the nearest suitable airport.

(b) The individual, as pilot, is responsible for the safety of the flight and must remain cognizant of those factors that are important in its successful completion. Accordingly, in recognition of such elements as adverse weather, turbulence, air traffic control changes, or other variables, the individual may decide that a scheduled, hourly measurement of blood glucose concentration during the flight is of lower priority than the need for full, undivided attention to piloting. In such cases, the individual shall ingest a 10 gm glucose snack. One hour after ingestion of this glucose snack, the individual shall measure and document his or her blood glucose concentration. If the individual is unable to perform the measurement of his or her blood glucose concentration for the second consecutive time, the individual shall ingest a 20 gm glucose snack and shall land as soon as practicable at the nearest suitable airport. The individual, under these circumstances, is not required to measure and document his or her blood glucose concentration within 1/2 hour prior to landing.

3. Prior to landing. Except as noted above, the individual must measure and document his or her blood glucose concentration within 1/2 hour prior to landing.

For subsequent certification:

Individuals with ITDM who are granted special issuance of third-class airman medical certificates must:

A. Submit to a medical evaluation by a specialist every 3 months. This evaluation must include a general physical examination, a report of glycated hemoglobin (total A1 or A1C) concentration and any other tests deemed necessary by the treating specialist or that are clinically indicated. This evaluation shall also contain an assessment of the individual's continued ability and willingness to monitor and manage properly his or her diabetes and of whether the individual's diabetes or its complications could reasonably be expected to adversely affect his or her ability to safely control an aircraft.

B. Carry and use a digital whole blood glucose measuring device with memory that is acceptable to the FAA. Provide records of all daily blood glucose measurements for review by the specialist at each 3-month evaluation required above and, if required, to the FAA at any time.

C. Provide to the FAA, on an annual basis, written confirmation by a specialist that the individual's diabetes remains under control and without significant complications and that he or she has demonstrated reasonable accuracy and recordation of his or her blood glucose measurements with the


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above described device. This report must also include the results of the quarterly evaluations outlined in Paragraph A above.

D. Provide to the FAA, on an annual basis, confirmation by an ophthalmologist of the absence of clinically significant disease that would prevent the individual from meeting current visual standards.

E. Provide to the FAA, immediately, a written report of any episode of hypoglycemia associated with cognitive impairment, whether or not it resulted in an accident or adverse event.

F. Provide a written report to the FAA, immediately, of involvement in any accidents, including those involving aircraft and motor vehicles, or other significant adverse events, whether or not they are believed related to an episode of hypoglycemia.

G. Provide to the FAA, immediately upon determination by a specialist or other physician, any evidence of loss of diabetes control, significant complications, or inability to manage the diabetes. In such a case, the individual shall cease exercising the privileges of his or her airman certificate until again cleared medically by the FAA.


Hearing and Noise in Aviation


by Melchor J. Antuñano, MD, and James P. Spanyers

The term hearing describes the process, function, or power of perceiving sound. Hearing is second only to vision as a physiological sensory mechanism to obtain critical information during the operation of an aircraft. The sense of hearing makes it possible to perceive, process, and identify among the myriad of sounds from the surrounding environment. Anatomy and Physiology of the Auditory System The auditory system consists of the external ear, ear canal, eardrum, auditory ossicles, cochlea (which resembles a snail shell and is filled with fluid), and the auditory nerve.Ambient sound waves are collected by the external ear, conducted through the ear canal, and cause the eardrum to vibrate. Eardrum vibration is mechanically transmitted to the ossicles, which, in turn, produce vibration of a flexible window in the cochlea. This vibration causes a pressure

wave in the fluid located inside the cochlea, moving thousands of hair-like sensory receptors lining the inner walls of the cochlea. The movement of these receptors resembles the gentle movement of a crop field caused by the wind. The stimulation of these sensors produces an electrical signal that is transmitted to the brain by the auditory nerve. This signal is then processed by the brain and identified as a particular type of sound.

Sound The term sound is used to describe the mechanical radiant energy that is transmitted by longitudinal pressure waves in a medium (solid, liquid, or gas). Sound waves are variations in air pressures above and below the ambient pressure. From a more practical point of view, this term describes the sensation perceived by the sense of hearing. All sounds have three distinctive variables: frequency, intensity, and duration.

Frequency is the physical property of sound that gives it a pitch. Since sound energy propagates in a wave-form, it can be measured in terms of wave oscillations or wave cycles per second, known as hertz (Hz). Sounds that are audible to the human ear fall in the frequency range of about 20-20,000

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Hz, and the highest sensitivity is between 500 and 4,000 Hz. Sounds below 20 Hz and above 20,000 Hz cannot be perceived by the human ear. Normal conversation takes place in the frequency range from 500 to 3,000 Hz.

Intensity is the measurement of pressure, or loudness. The decibel (dB) is the unit used to measure sound intensity. The range of normal hearing sensitivity of the human ear is between -10 to +25 dB. Sounds below -10dB are generally imperceptible. A pilot who cannot hear a sound unless its intensity is higher than 25 dB (at any frequency) is already experiencing hearing loss.

Duration determines the quality of the perception and discrimination of a sound, as well as the potential risk of hearing impairment when exposed to high intensity sounds. The adverse consequences of a short-duration exposure to a loud sound can be as bad as a long-duration exposure to a less intense sound. Therefore, the potential for causing hearing damage is determined not only by the duration of a sound but also by its intensity.

Noise

The term noise refers to a sound, especially one which lacks agreeable musical quality, is noticeably unpleasant, or is too loud. In other words, noise is any unwanted or annoying sound. Categorizing a sound as noise can be very subjective. For example, loud rock music can be described as an enjoyable sound by some (usually teenagers), and at the same time described as noise by others (usually adults).

The aviation environment is characterized by multiple sources of noise, both on the ground and in the air. Exposure of pilots to noise became an issue following the introduction of the first powered aircraft by the Wright brothers and has been a prevalent problem ever since. Noise is produced by aircraft equipment-powerplants, transmission systems, jet efflux, propellers, rotors, hydraulic and electrical actuators, cabin conditioning and pressurization systems, cockpit advisory and alert systems, communications equipment, etc. Noise can also be caused by the aerodynamic interaction between ambient air (boundary layer) and the surface of the aircraft fuselage, wings, control surfaces, and landing gear. These auditory inputs allow pilots to assess and monitor the operational status of their aircraft. All pilots know the sounds of a normal- functioning aircraft. On the other hand, unexpected sounds or the lack of them, may alert pilots to possible malfunctions, failures, or hazards. Every pilot has experienced a cockpit or cabin environment that was so loud that it was necessary to shout to be heard. These sounds not only make the work environment more stressful but can, over time, cause permanent hearing impairment. However, it is also important to remember that individual exposure to noise is a common occurrence away from the aviation working environment-at home or work, on the road, and in public areas. The effects of pre-flight exposure to noise can adversely affect pilot in-flight performance.

Types of Noise

● Steady: Continuous noise of sudden or gradual onset and long duration (more than one second). Examples: aircraft powerplant noise, propeller noise, and pressurization system noise. According to the Occupational Safety and Health Administration (OSHA), the maximum permissible continuous exposure level to steady noise in a working environment is



90 dB for eight hours.● Impulse/Blast: Noise pulses of sudden onset and brief duration (less than one second) that

usually exceed an intensity of 140 dB. Examples: firing a handgun, detonating a firecracker, backfiring of a piston engine, high-volume squelching of radio equipment, and a sonic boom caused by breaking the sound barrier. The eardrum may be ruptured by intense levels (140 dB) of impulse/blast noise.

Effects of Noise Exposure Physiological

● Ear discomfort may occur during exposure to a 120 dB noise.● Ear pain may occur during exposure to a 130 dB noise.● Eardrum rupture may occur during exposure to a 140 dB noise.● Temporary hearing impairment. Unprotected exposure to loud, steady noise over 90 dB for a

short time, even several hours, may cause hearing impairment. This effect is usually temporary and hearing returns to normal within several hours following cessation of the noise exposure.

● Permanent hearing impairment. Unprotected exposure to loud noise (higher than 90 dB) for eight or more hours per day for several years, may cause a permanent hearing loss. Permanent hearing impairment occurs initially in the vicinity of 4,000 Hz (outside the conversational range) and can go unnoticed by the individual for some time. It is also important to remember that hearing sensitivity normally decreases as a function of age at frequencies from 500 to 6,000 Hz, beginning around age 30.

Psychological

● Subjective Effects: Annoying high-intensity noise can cause distraction, fatigue, irritability, startle responses, sudden awakening and poor sleep quality, loss of appetite, headache, vertigo, nausea, and impair concentration and memory.

● Speech Interference: Loud noise can interfere with or mask normal speech, making it difficult to understand.

● Performance: Noise is a distraction and can increase the number of errors in any given task. Tasks that require vigilance, concentration, calculations, and making judgments about time can be adversely affected by exposure to loud noise higher than 100 dB.

How to Protect Your Hearing Limiting Duration of Exposure to Noise: OSHA-established permissible noise exposure limits for the workplace (Fiugure 2) (including the cockpit of an aircraft).

Use Hearing Protection Equipment. If the ambient noise level exceeds OSHA's permissible noise exposure limits, you should use hearing protection devices-earplugs, earmuffs, communication headsets, or active noise reduction headsets. Even if an individual already has some level of permanent hearing loss, using hearing protection equipment should prevent further hearing damage. These protection devices attenuate noise waves before they reach the eardrum, and most of them are effective at reducing high-frequency noise levels above 1,000 Hz and/or for reducing noise levels to,



or below, 50 dB. It is very important to emphasize that the use of these devices does not interfere with speech communications during flight because they reduce high-frequency background noise, making speech signals clearer and more comprehensible.

● Earplugs. Insertable-type earplugs offer a very popular, inexpensive, effective, and comfortable approach to provide hearing protection. To be effective, earplugs must be inserted properly to create an air-tight seal in the ear canal. The wax-impregnated moldable polyurethane earplugs provide an effective universal fit for all users and provide 30 to 35 dB of noise protection across all frequency bands.

● Communication Headsets. In general, headsets provide the same level of noise attenuation as earmuffs, and are also more easily donned and removed than earplugs, but the microphone can interfere with the donning of an oxygen mask.

● Active Noise Reduction Headsets. This type of headset uses active noise reduction technology that allows the manipulation of sound and signal waves to reduce noise, improve signal-to-noise ratios, and enhance sound quality. Active noise reduction provides effective protection against low-frequency noise. The electronic coupling of a low-frequency noise wave with its exact mirror image cancels this noise.

● Combinations of Protection Devices. The combination of earplugs with earmuffs or communication headsets is recommended when ambient noise levels are above 115 dB. Earplugs, combined with active noise reduction headsets, provide the maximum level of individual hearing protection that can be achieved with current technology. [Editor's Note: Be careful you don't muffle too much engine noise when you combine ear protection devices. You still want to hear enough to know if the engine quits.]

This article is adapted from a pamphlet of the same name in the series "Medical Facts for Pilots," developed by FAA's Civil Aeromedical Institute. If you want additional copies or more information on hearing, contact CAMI's Aeromedical Education Division, AAM-400, P.O. Box 25082, Oklahoma City, OK 73125.

Dr. Antuñano manages CAMI's Aeromedical Education Division; Mr. Spanyers is a physiology instructor in the same organization.


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THE MOST FREQUENTLY ASKED QUESTIONS REGARDING MEDICAL CERTIFICATION OF PILOTS

1. What is a medical certificate? Flying is a fascinating and enjoyable experience, whether done for business or pleasure. Flying has the potential, however, for serious consequences if not done properly and carefully. Just as it would be foolish to fly in an aircraft that is not airworthy, it would be foolish to fly as, or with, a pilot who is medically compromised. Annual inspections are performed on all aircraft to assure that they meet minimum safety standards. Routine medical exams accomplish the same goal for pilots. When an aircraft successfully completes an annual inspection, the inspector endorses in the logbooks

that the aircraft is airworthy. Similarly, when a pilot successfully passes the flight physical, the physician endorses the medical certificate which the pilot then carries with him/her each time he/she flies. This is then evidence that the pilot has met the medical standards for aircraft operation.

2. Who is required to hold a Federal Aviation Administration (FAA) Medical Certificate? Any person acting as pilot-in-command or other required crewmember of an aircraft (except for free balloons, gliders, and ultralights) must hold a current and appropriate medical certificate. This includes student pilots in solo flight as well as private, commercial, and airline pilots.

3. How does one get a medical certificate? The FAA has designated over 5000 private physicians (called Aviation Medical Examiners or AMEs) around the United States (and the world) to take applications for, give exams for, and issue FAA medical certificates. A list of FAA designated medical examiners is available. The applicant simply contacts the physician's office for an appointment and after arrival, completes an application form and undergoes the physical examination. If the applicant meets the appropriate medical standards, the AME will issue the medical certificate.

4. What types of medical certificates are available and how long are they good for? There are three classes of medical certificates:

Class 3 medical certificates are for private pilot duties only. They have the least restrictive medical requirements and the certificates are generally good for 3 years for applicants under age 40 and 2 years for those 40 and over.

Class 2 medical certificates are for commercial, non-airline duties as well as private pilot duties. This certificate would be required of crop dusters, charter pilots, corporate pilots, and anyone else who flies commercially. The certificate is good for 1 year for commercial activities and 2 or 3 years for private pilot use.

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Class 1 medical certificates are required for pilots of scheduled airliners. They have the most stringent medical requirements and the certificate is good for 6 months for airliner duties. Like the Class 2 certificate, however, it is good for 1 year for other commercial activities and 2 or 3 years for private pilot duties.

5. What medical standards must be met to be issued each of the above certificates? The medical standards for each class of medical certificate are put forth in Part 67 of the Federal Aviation Regulations (14 CFR 67).

6. What are the minimum and maximum ages for obtaining a medical certificate? There is no minimum or maximum age, per se, for obtaining a medical certificate. Any applicant who is able to pass the exam may be issued a certificate. However, an applicant under the age of 16 (the minimum age for a student pilot certificate) will not be able to obtain an airman certificate (pilot's license) and would therefore have no practical use for the medical certificate.

7. Can I get my student pilot certificate at the same time I take my initial flight physical? Yes. AME's are authorized to issue combination Airman Medical and Student Pilot certificates to appropriate applicants. To obtain this combination certificate, the applicant must not only meet the medical standards but must also be at least 16 years old and be able to read, speak, and understand the English language. If these requirements are met, the AME will issue the combined certificate. PLEASE NOTE: The combined medical / student pilot certificate will not be good for flight duties until properly endorsed by the student's instructor.

8. What does it cost to get a medical certificate? The FAA does not set fees for the performance of the medical exam and issuance of the medical certificate. The AME is allowed to charge the applicant appropriately, as long as it is not more than his/her usual fee for similar examinations for other purposes. If you are concerned about the cost of the exam, please discuss this with the doctor you are thinking about seeing. The FAA has no additional fees above what the physician charges.

9. I have some minor medical problems and would like to find out whether or not they will create difficulties when I go to get my medical certificate. Who could I contact in order to get further information about my situation? There are several sources for information regarding the various medical conditions that might afflict applicants for medical certification. One source is your local AME. This physician (see Question 3 above) may be willing to discuss your medical problems and the impact they are likely to have on certification. Frequently, AMEs will do this over the phone without charge. Another alternative is to contact the FAA directly, either through your Regional Flight Surgeons office or through us, the Aeromedical Certification Division of the FAA in Oklahoma City. Our office is open from 8:00 AM to 4:30 PM Central Time during regular weekdays. The phone number is (405) 954-4821. (Be patient. We get a lot of calls.)

A third source of information is through the various pilot organizations such as the Experimental Aircraft Association (EAA) at 1-800-564-6332 or the Aircraft Owners and Pilots Association (AOPA) at 1-800-872-2672.


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10. If my application for medical certification is turned down, what recourse do I have? Part 67 of the Federal Aviation Regulations outlines the appeal process for applicants who are denied medical certification. In a nut shell, the initial appeal would be to the Federal Air Surgeon (through our Oklahoma City office) to request an authorization for the special issuance of a medical certificate. This might result in a medical certificate that is time-limited, contingent upon the successful completion of addition medical testing, or otherwise restricted. If this request is not successful, then an appeal to the National Transportation Safety Board (NTSB) could be made. If the NTSB concurs with the FAA's denial action, you could then request a hearing in Federal District Court and ultimately the Supreme Court.

11. What happens if I get my medical certificate and then I have some sort of medical problem that develops before the certificate expires? Do I have to report it and do I have to ground myself? Can I keep on flying until the certificate expires? The regulations are quite clear that, despite the presence of an unexpired medical certificate, it is still your responsibility as a pilot to maintain your health. If you develop a new medical condition or experience the worsening of an existing medical condition such that you may no longer meet the medical requirements, then you must not fly until the problem is resolved. A simple problem such as a cold, a broken arm, or an abscessed tooth may require nothing more than the appropriate treatment and a little time before you can safely return to the skies. A more complicated problem or the development or change of a chronic illness may necessitate consultation with an AME or the FAA before flying resumes. As long as you choose not to fly, the medical condition does not need to be reported to the FAA until you wish to return to flying.


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Long Distance Flying May Cause Jet Lag

Anyone who has flown across several time zones has experienced jet lag. This mismatch between the time your body clock is set to....and the actual time at your destination....can take days to overcome. For example, if you arrive in Europe from Chicago, your body may expect it to be midnight, but your eyes perceive it is 6 a.m. Your body is tired, and yet, you have a whole day ahead in Europe. If you sleep too long upon arrival, then when bedtime arrives, you're not tired. Jet lag produces fatigue, lack of alertness, loss of stamina and reduced productivity. The strategies in this brochure won't cure jet lag, but may help you overcome its effects and sleep better. If you plan to be away from home for less than 3 days, try to stay on your home time. Sleep and eat

when you normally would at home and keep your watch set to home time. However, if that is not possible or if you are away longer, here are some suggestions to cut your recovery time. A two-day schedule for traveling up to 9 hours east or west is provided. If you travel farther than 9 hours, either schedule can help.

Travel East

If you travel east across 6-9 time zones your body clock must advance....you will be trying to sleep when your body is set to be awake. (All times are local)

Day 1 at destination Take a long nap (3-4 hours) sometime between 9 a.m. and 2 p.m. Be careful not to exceed 4 hours. Begin your nighttime sleep as close to 9 p.m. as possible and get up as close to 5 a.m. as possible. Go outside in the fresh air, but avoid prolonged (20 minutes) sunlight exposure before 1 p.m. Be sure to wear sunglasses. After 1 p.m. go out and enjoy the sun. A brisk afternoon walk is helpful.

Day 2 at destination Take a short nap (30-40 minutes) sometime between 11a.m. and 1p.m. Try to get to bed around 10 p.m. and get up around 6 a.m. Again, avoid prolonged sunlight until after 1 p.m. Another brisk walk and lots of fresh air speeds your adjustment. After the second day, try to eat and

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sleep on the local time schedule and be consistent in your sleep and wake times. If you are still tired the next day, try a short nap during lunch time.

Travel West

If you travel west 6-9 time zones your body clock must delay....you are sleeping when your body is receptive to sleep. Most travelers find going west much easier than going east.

Day 1 at destination If you are tired, take a short nap (30-40 minutes) between 2 and 6 p.m. Avoid taking a longer nap. Get to bed around 8 p.m. and get up as close to 4 a.m. as possible. Get out in the fresh air. Take a morning walk. Avoid the sunlight after 4 p.m.

Day 2 at destination Take a short nap between 12 and 3 p.m. Go to bed around 10 p.m. and get up around 6 a.m. Try to keep this schedule of sleep for the remainder of your visit. Walks, fresh air and short naps help if you get tired during the day.

Relaxation Tips

Sometimes the key to restful sleep is relaxation. Here are some tips.

Lie comfortably on your back. Close your eyes and take slow deep breaths. Try to use your stomach muscles, not chest, to breathe in and out. Inhale slowly for about 4 seconds, hold your breath for 2 seconds and exhale for 4 seconds. Start with 4 or 5 of these relaxing breaths until you feel comfortable with this technique.

While breathing deeply, visualize a very pleasant but simple scene.

Tense and relax each muscle group in order: fists, then arms, shoulders and upper back, face, toes and feet, calves, thighs, buttocks, lower back and stomach. Squeeze each muscle group, simultaneously on the right and left sides of your body, as hard as you can, for about 4 seconds.

Then take a few deep breaths.

Sleep Smarter

Sleep is a basic human need, like eating but more compelling. To be at our best, most of us need 7-8 hours of uninterrupted sleep each night.

If you are accumulating a "sleep debt" and feel tired, here are some recommendations to help you sleep better:

Sleep at consistent times. You will sleep better if you go to bed and wake up at the same time, including weekends.


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Avoid alcohol, especially during the 2-3 hours before bed.

Avoid stimulants (coffee, chocolate, soft drinks, tea) during the 3-5 hours before bed. Find out if any drugs you take impair sleep (for example, some decongestants and anti-inflammatory drugs).

A warm bath, brushing your teeth or just washing your face and hands can make you more comfortable.


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Night Operations

Humans regard vision as their most valuable sense, yet they fail to appreciate what a remarkable and complicated organ the human eye is. The human eye has reached the absolute threshold of sensitivity to light and, under certain ideal conditions, can see a candle flame at a distance of over 15 miles. All eyes--including a cat's--are alike in that none of them can see in total darkness. Most people are completely uninformed about night vision and feel that there is nothing to be learned about the subject. However, it is important for the pilot to understand the construction of the human eye, since it is so constructed that to see effectively at night it must be used differently from the daytime. The eye might be compared to a camera, since it consists of a lens that focuses the image upon

the retina which corresponds to film in the camera. The retina is made up of various layers of cells, among them the significant cells for vision--the rods and cones. The cones, of which there are more than seven million in each human eye, are packed closely together in the very center of the retina. The rods are concentrated in a ring around the cones.

The function of the cones is to detect color, details, and far away objects. The rods function when something is seen out of the corner of the eye. They detect objects, particularly moving ones, but do not give detail or color, only shades of gray. Both the cones and the rods are used for vision during daylight and bright moonlight. In the absence of these, the process of vision depends almost entirely upon the rods. When the rods become adjusted to darkness--a process which requires about 30 minutes--they become about 100,000 times more sensitive to light than they were during daylight. However, the fact that rods are distributed in a band around the cones makes "off center" viewing important during night flight.

During daylight an object is best seen by looking directly at it, but at night a scanning procedure to permit "off center" viewing of the object is more effective. The pilot should consciously practice this scanning procedure to improve night vision. Smoking, the presence of carbon monoxide, hypoxia,

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Vitamin A deficiency, and the use of certain drugs adversely affect the eyes' night vision capabilities. It is important for the pilot to maintain good physical condition.

Cockpit lighting is also of extreme importance. While dim red lighting has the least adverse effect on night vision, it severely distorts colors. Older pilots may experience extreme difficulty in focusing the eyes on objects inside the cockpit.

The tendency in recent years has been toward the use of diffused white or blue-white instrument lighting. In addition to night vision, the pilot should also be aware of how to cope with illusions encountered during night flight. Refer to Advisory Circulars 61-23B, "Pilot's Handbook of Aeronautical Knowledge," and 61 21A, "Flight Training Handbook," and the Aeronautical Information Manual for further information on the above subjects.

by Chuck Urquhart

Mr. Urquhart is a designated pilot examiner in the Pittsburgh, PA area.

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Trapped Gas

As an instructor with CAMI's Physiological Training program, we cover a variety of subjects that deal with the problems of pressure change at altitude, and its effects on the human body. One of these areas is the effects of pressure change on the middle ear, parasinuses, gastrointestinal tract, and the teeth. These areas can withstand enormous changes in barometric pressure as long as the air pressures within these body cavities are equalized with the pressure surrounding them. The mechanical responses to changes in pressure are in accordance with Boyle's Law, which states that a volume of gas is inversely proportional to the pressure to which it is subjected, temperature remaining constant. When the gases in these cavities can't equalize with the ambient environment, the gas is considered to be "trapped."

Of the areas of trapped gas, the most commonly dealt with is that of the middle ear. There is seldom any difficulty upon ascent; most often difficulty is experienced on descent in the form of an ear block (barotitis media). An ear block is usually preceded by a fullness in the ear, gradual loss of hearing and eventually pain. From my experiences in the chamber, I have drawn the conclusion that most ear blocks are a result of not knowing how to properly equalize the pressure in the middle ear, or trying to fly with a cold.

Normally, there is little difficulty equalizing pressure during descent, by occasionally swallowing, yawning, or tensing the muscles of the throat; this will allow the pressure to equalize. During sleep, the rate of swallowing slows down. For this reason, it is advisable to awaken sleeping passengers prior to descent for the purpose of permitting them to ventilate their ears. Infants should be given a bottle or pacifier to aid in equalization. Small children can avoid difficulty by chewing gum.

If these actions fail to equalize the pressure, a Valsalva maneuver should be performed. The Valsalva maneuver is performed by closing the mouth, pinching the nostrils closed and blowing air through the nose. This will force air up the eustachian tube and into the middle ear. This is not a dangerous procedure and should not be delayed until the pressure in the ears becomes painful, otherwise it may be extremely difficult to open the eustachian tube. Painful ear blocks generally occur when the descent rate is too rapid. To relieve this pain, a level off and ascent to a higher altitude is recommended. This should be followed by a slower descent, if possible. During the second descent, close attention must be given to the prompt use of equalization techniques. Prudent use of antihistamines and/or decongestants may also prove to be very helpful but should be used sparingly due to their compounding effect with hypoxia.*

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Along with the lack improper equalization maneuvers, flying with a cold can be just as much a problem, if not more so. Equalization of the middle ear can be impaired when the eustachian tube, or its opening, becomes restricted as the result of inflammation, upper respiratory infection, sore throat, infection of the middle ear, or sinusitis. It may be possible to equalize the middle ear by a forceful Valsalva, but this may result in the infected material being carried into the eustachian tube, along with the air causing infection of the middle ear. Since the resulting infection may result in a longer grounding than the cold, it may be advisable not to fly if you suspect you have a cold

After a flight in which you use 100 percent oxygen, the Valsalva procedure should be accomplished several times to ventilate the middle ear. This is recommended because the middle ear will be filled with pure oxygen, which is then gradually absorbed by the tissue of the middle ear. This, in turn, will cause a reduction of pressure, which may become painful later in the day, or night, if left unequalized.

For those who have experienced a sinus block (barosinusitis), to some degree it is not a pleasant experience. My personal experience occurred within an altitude chamber on a rapid descent (12,000 feet per minute) from 43,000 feet (unpressurized). At approximately 22,000 feet, it felt as though someone or something had softly touched me above my right eyebrow, and within seconds, it felt as though a sharp object was being forced into the same area. We immediately leveled off and then ascended 2,000 feet at approximately 12,000 feet per minute. The pain immediately ceased and Afrin was administered. We slowed the descent rate down and I had no further complications.

The sinuses most often affected by pressure change are the frontal and the maxillary sinuses. These air-filled, rigid, bony cavities lined with mucous membrane are connected with the nasal cavity by means of one or more small openings. When these openings into the sinuses are normal; air passes through these cavities without difficulty, and can accommodate any moderate rate of ascent or descent. If the openings of the sinuses are obstructed by the swelling of the mucous membrane lining, ready equalization of pressure becomes difficult and the possibility of a sinus block will increase. This is another example of what could happen as a result of flying, or diving with a cold. Keep in mind that most sinus blocks occur on descent and will give little or no warning.

When the maxillary sinuses are affected, the pain will probably be felt on either side of the nose, under the cheek bones. Maxillary sinusitis may produce pain referred to the teeth of the upper jaw and may be mistaken for a toothache.

When the frontal sinuses are affected, the pain will be located above the eyes and usually is quite severe. This type of sinus problem is the most common.

Equalization of pressure to relieve pain in the sinuses is best accomplished by use of the Valsalva procedure, and/or inhalants, previously mentioned in conjunction with ear blocks. Again, you should be very cautious in your use of any over the counter medication.* Reversing the direction of pressure change as rapidly as possible may be necessary to clear severe sinus blocks.

As mentioned before, the middle ear is the most common generator of discomfort upon descent.


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The gastrointestinal tract, however, is the area most commonly associated with pain or discomfort upon ascent. This discomfort is caused by the expansion of gas within the digestive tract during ascent. Fortunately, the symptoms are not serious in most individuals, although in flights above 25,000 feet, enough distention may occur to produce severe pain.

The gastrointestinal tract normally contains variable amounts of gas with pressure approximately equivalent to that of the ambient atmosphere. The chief sources of this gas are swallowed atmospheric air and, to a lesser extent, gas formed as a result of the digestive processes. As gases in the stomach and intestines expand during ascent, extreme discomfort can occur unless there is relief, ordinarily obtained by belching or by passing flatus.

Gas pains of even moderate severity may result in lowered blood pressure. Shock, or syncope, will be the eventual result if relief from distention is not obtained. Immediate descent from altitude should be made to obtain relief.

It can be beneficial to you as a pilot, crew member, or passenger to be aware of certain things before you fly. For instance, if you have a cold, maybe you should pass on that day's flight.

Another area to plan ahead for is to watch what you eat before you fly. Staying away from foods you know cause you problems could help you avoid, or lessen, the discomfort or pain in the gastrointestinal tract. Some of the foods that more commonly disagree with individuals are: onions, cabbage, raw apples, radishes, dried beans, cucumbers, melons-or any food that you know causes you problems.

It is probably wise to avoid carbonated beverages in large quantities, as well as anything else bubbly immediately before flight. One thing that we stress in our course, is that, every individual is different and has different tolerances. Because of this, it is important to know what affects you, not what affects someone else.

Of all the areas of possible trapped gas problems, tooth pain (barondontalgia) is the least common. A toothache may occur at altitude during flight. The pain may, or may not, become more severe as altitude is increased, but descent almost invariably brings relief. The toothache often disappears at the same altitude at which it was first observed on ascent.

Common sources of this difficulty are abscesses, mechanically imperfect fillings (very rare in occurrence), inadequately filled root canals, and pulpits. Anyone who experiences a toothache at altitude should see a dentist without delay for examination and treatment. As mentioned before, maxillary sinus discomfort may be misinterpreted as a toothache.

The Physiological Training course provides comprehensive instruction on trapped gas problems during flight. The course can be attended at a military installation in your area or at the Civil Aeromedical Institute in Oklahoma City. For more information, contact the Airman Education Programs Branch at 405-954-4837.


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by Roger Storey


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Ultraviolet Radiation

Protection Against Exposure

In a previous article [Federal Air Surgeon's Medical Bulletin, Winter 1994], we discussed what ultraviolet (UV) radiation is and how it has been associated with numerous ocular disorders, particularly cataracts. We also learned that pilots may be at greater risk for exposure than non-pilots. In this article, we will focus our attention on how to best protect the pilot from UV radiation. Ulraviolet Radiation reaches the eye not only from the sky above, but also by reflection from the ground, especially water, snow, sand, and other bright surfaces. Protection from sunlight can be obtained by using a brimmed hat or cap and UV absorbing eyewear. A hat or cap can reduce UV radiation by about 50%. Ultraviolet absorbing eyewear provides the greater measure of UV protection,

particularly if it has a wraparound design to limit the entry of peripheral rays. For outdoor use in bright sun, sunglasses that absorb 99-100% of the full UV spectrum up to 400 nanometers are recommended. There is presently no uniform labeling of sunglasses that provides adequate information to the consumer. If labels are available, they should be examined carefully to ensure that the lenses purchased absorb at least 99-100% of both UV-B (280 to 315 nanometers) and UV-A (315 to 400 nanometers).

The standard for UV transmittance in sunglasses is being debated. The Non-Prescription Sunglasses and Fashion Eyewear requirements, adopted by the American National Standards Institute (ANSI) Z80.3 Committee, identify three categories of sunglasses: Cosmetic use, General purpose (for use in any outdoor activity), and Special purpose (for use in very bright environments). The UV requirements for these categories are: Cosmetic use -blocks at least 70% UV-B and 20% UV-A; General purpose - blocks at least 95% UV-B and 60% UV-A; and Special purpose - blocks at least 99% UV-B and 60% UV-A. While ANSI allows 5% transmittance of UV-B for general purpose lenses, a recent announcement from the US Food and Drug Administration (FDA), reports it plans to allow only 1% transmission of UV-B and <5% of UV-A.

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The American Optometric Association's (AOA) Commission on Ophthalmic Standards recently revised the testing protocol for its Seal of Acceptance program for non-prescription sunglasses and fashion eyewear. The new specifications require that sunglasses transmit no more than 1% UV-A and UV-B to receive the AOA Seal of acceptance. These new requirements are in concurrence with the joint position statement on ultraviolet radiation hazards in sunlight recently adopted by the AOA, Prevent Blindness America, and the American Academy of Ophthalmology.

For contact lens wearers, UV-absorbing contact lenses have been shown to provide excellent UV protection as compared to untreated lenses. For aphakic patients, UV-absorbing intraocular lenses are available and may be preferable for the pilot population. If these are not viable alternatives, recommending an appropriate UV-absorbing spectacle lens would be justified.

In summary, general recommendations for individuals at risk for high exposure to UV, include:

Wear a cap or wide-brimmed hat in the bright sunlight;

Wear approved UV-absorbing sunglasses outdoors;

For those with specialty ophthalmic devices (contact lenses, intraocular lens implants), UV-absorbing material should be incorporated into such devices and/or combined with appropriate UV-absorbing spectacle lenses.

REFERENCES

Ocular Ultraviolet Radiation Hazards in Sunlight. National Society to Prevent Blindness. American Optometric Association. The American Academy of Ophthalmology. November 10, 1993.

Testing Protocol for Non-Prescription Sunglasses and Fashion Eyewear. American Optometric Association. Commission on Ophthalmic Standards, October 1993.

Harris MG, Dang M, Garrod S, Wong W. Ultraviolet Transmittance of Contact Lenses. Optometry and Vision Science. 1994; 71(1):1-5. Sliney D and Wolbarsht M. Safety with Lasers and Other Optical Sources: A Comprehensive Handbook. New York: Plenum Press, 1980.

Pitts DG and Kleinstein RN. Environmental Vision: Interactions of the Eye, Vision, and the Environment. Boston: Butterworth-Heinemann, 1993.

By Van Nakagawara, OD Dr. Nakagawara is the coordinator of the Civil Aeromedical Institute's Vision Research Team, Aeromedical Research Division.

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Vitamins

Some Practical Facts About Vitamins

by Glenn L. Stoutt, Jr., MD

Vitamins are substances vital for biochemical reactions in the body. Forget about all the chemistry and biology. We need an answer to the following question: Does (as we have been told over and over) an adequate, balanced diet provide all the vitamins and minerals needed in the otherwise healthy person? At present, neither The American Heart Association nor The American Cancer Society has formally recommended vitamin or mineral supplements. The prevailing conventional wisdom from many experts says that diet is enough. However, there is much more to consider. How many people actually eat an adequate, balanced diet every day or even most days? This theoretical, optimum diet would be loaded with fresh fruits

and vegetables, plenty of whole grain breads and cereals, low-fatdairy products, skinless poultry, fish, and lean meats that are low in saturated fat and cholesterol--and includes foods with plenty of fiber and minerals. But our typical diet might include fruits on Monday and then no more until Saturday; vegetables once a week; fast-food meals six times a week; cereal one morning; fish on Friday; a candy bar and peanut butter and crackers from a vending machine on Saturday, five colas a week; and too many alcoholic drinks on weekends. So, really, there is no way most of us would get the needed amount of vitamins.

Standards

● MDR refers to the Minimum Daily Requirement● RDA to the Recommended Daily Requirement● RDI to the Reference Daily Intake● ODA means Optimum Daily Allowance● DV refers to the Daily Value.

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Help! Where do all these confusing standards come from? Various groups developed recommendations that turn out to be based on unrealistic statistical norms, overlooking individual differences.

Actually, the minimum daily requirement refers to the absolute minimum amount one needs of the vitamin, a bare-bones amount that will keep you from getting a vitamin deficiency, say scurvy from lack of vitamin C or rickets from lack of vitamin D.

True, in medical practices in the United States, vitamin deficiency diseases are almost non-existent. But, what about problems resulting from marginal intake of vitamins--from being close to "running on empty?"

Do we need more--or in the case of vitamin C, much more--than the recommended amounts? How much does one need for optimum health?

The "just eat right" suggestion overlooks vast differences in age, sex, weight, lifestyle, activity, health, heredity, stress, climate, and individual biochemistry.

Much present-day thinking is that these recommendations should be changed. Vitamins may do much to prevent heart disease, cancer, and aging, plus help to keep us active, feeling good, and in optimum health. So, do we need vitamin supplements?

Many experts now think so. Of course, at the basis of all discussions of vitamins and minerals is the assumption that we must eat a healthful, balanced diet--as the first step toward good health. Supplemental vitamins are the second step.

Reasons vitamin Supplements Are Recommended:

● The B vitamins folic acid, B6, and B12 lower homocysteine levels in the blood. New studies indicate that elevated homocysteine may promote atherosclerosis and blood vessel damage as much as cholesterol. Inexpensive tests for homocysteine will soon be available.

● It's now generally accepted that heavy accumulation of free radicals that result from our body's metabolism and energy use can damage healthy cells. These agents can contribute to cardiovascular disease, cancer, cataracts, aging, arthritis, and damage to our DNA. This toxic damage can be lessened by antioxidants. The three major antioxidants are vitamin C, vitamin E, and betacarotene.

Kenneth H. Cooper, MD, health and fitness guru, and author of Aerobics, has written an entire book devoted to this subject. He noted that many athletes who overtrained (high-intensity, exhaustive exercise) succumbed to heart attacks and cancer. He theorized that the overexertion produced high levels of free radicals, which then injured cells lining the arteries, contributed to other cells becoming cancerous. He now recommends low-intensity exercise to replace the killer-paced regimens that many feel a compulsion to perform. As a part of our regular health program, his book advises adults


Vitamins

to have a daily "cocktail" of the three antioxidants.

Natural Sources of Antioxidants, Supplements, and Daily Needs For vitamin C, the answer is pretty easy. Most fruits and vegetables contain plenty of C (also called ascorbic acid). Take more than the recommended minimum allowance of about 60 milligrams (mg) a day that one can easily get from your diet. Dr. Cooper suggests taking a supplement of at least 500 mg per day. Costs about two cents a day.

You just can't get enough vitamin E from your diet. It is in vegetables, wheat germ, and vegetable oils such as safflower, corn, and sunflower. The animal products that are high in vitamin E also contain high fat, so this is not such a good choice. A reasonable supplemental dose is 400 International Units (IU). Get natural vitamin E--it will say d-alpha tocopherol (or -yl) on the bottle.

With beta carotene dietary intake is the answer and the food choices make it easy. A large carrot and a large sweet potato--they each have very high levels-give you way over Dr. Cooper's recommendation of 25,000 I.U. daily.

A carrot has almost 25,000 I.U., and a baked sweet potato contains about 20,000 I.U.--the next closest foods have only about a third as much. So, get more bang for the buck by choosing sweet potatoes and carrots. Beta carotene is found in yellow and dark green vegetables. They are "color coded" by nature--making selections easy: carrots, sweet potatoes, pumpkins, yellow corn, spinach, kale, turnip greens, collards, winter squash, cantaloupes, oranges, and apricots.

Recent studies have shown that only natural beta carotene seems to have full protective effect, so you can probably omit this antioxidant from your shopping list. (Beta carotene is one of the precursors of vitamin A.)

The antioxidants vitamin C, beta-carotene (part of the vitamin A complex), and vitamin E help prevent many chronic diseases, including heart disease, cancer, cataracts, aging, depressed immune system, and DNA damage. They reduce levels of the toxic free-radicals that are produced by all biochemical reactions in the body.

So, what's the bottom line on vitamins and mineral supplements? To a healthful, balanced diet loaded with deeply-colored (carrots, oranges, spinach, cantaloupe, apples) fruits and vegetables, add:

● One multivitamin/mineral tablet a day● 500 mg of vitamin C● 400 IU of vitamin E● 1000-1500 mg of calcium (to prevent bone loss through osteoporosis)

Factoids


Vitamins

● A good multiple vitamin with minerals (generic) costs about three cents a day. You can get this, all the antioxidants, calcium (1000 mg), and a baby aspirin or equivalent (81 ma) for a total of 17 cents a day, or a little over five bucks a month.

● A little-known secret: Only a few companies, maybe four or five, make vitamins. They sell carloads of bulk vitamins to thousands of stores, who repackage them and sell them under their own brand name. So, the same batch of multivitamin/supplements may be sold under dozens of brand names and at many different prices. Generics cost much less than the name brand (fewer advertising dollars) but are exactly the same thing. A rule of thumb is to never spend over $10 a month for supplements. Avoid subscribing to expensive rip-off programs that send you a box of supplements costing enough money to start payments on a small car. The generic form sells for much less. Most supermarkets and discount stores carry their own line of reputable vitamins and supplements. Some companies offer "designer" vitamins and food supplements for an exorbitant cost. Don't get ripped off. Stay with the basics.

● If you are taking anticoagulants or large amounts of aspirin-the standard adult aspirin is 325 mg--don't take vitamin E without consulting your physician. Vitamin E is a natural anticoagulant.

● Natural vitamins have no advantage over synthetic ones, with the possible exception of vitamin E and beta carotene (part of vitamin A).

● Natural vitamin E is slightly more expensive, but is probably better than the synthetic form. One large carrot or one sweet potato daily will give you plenty of beta-carotene.

● Avoid the marketing ploys of such creative label prefixes as stress-, silver-, gold-, extra strength-, high potency-, vitamin C from rose hips, therapeutic formulas, or such. The only special vitamin/mineral supplements are those given to pregnant or nursing women.

● The minerals listed on the bottle label should include (at least) iron, zinc, calcium, selenium, iodine, magnesium, chromium, and copper.

● Chewable vitamin C (ascorbic acid) over the years might do a number on the enamel of your teeth. Just get plain vitamin C.

● The fat-soluble vitamins (A, D, E, and K) are stored in the body for a much longer time--for months--than the water-soluble ones, which can last for only a few weeks at most. The bad news is that the fat-soluble vitamins could, in massive doses, accumulate to a dangerous level. This is especially true of vitamins A and D, which in huge doses can actually be so toxic as to cause illness and even death. As in most things, more is not necessarily better.

● Take your vitamin/mineral supplements with meals for better absorption.● On the label, mg means milligram, or a thousandth of a gram; mcg refers to microgram, or a

millionth of a gram; I.U. means International Unit. While reading the label, make sure the product has not expired or will expire before you use all of it.

I can't see that any valid objection could be made to this schedule. It is a reasonable choice between the timid advice of the diet only people and the megadoses recommended by some people. People taking adequate vitamins are unquestionably healthier than those who do not. I personally think these recommendations are both safe and reasonable, and should answer the question, "Should l take vitamin/mineral supplements?"

Yours for good health and safe flying.


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Note: The views and recommendations made in this article are those of the author and not necessarily those of Avstop Dr. Glenn R. Stoutt, Jr., is a partner is the Springs Pediatrics and Aviation Medicine clinic, Louisville, Ky., and has been an active FAA Aviation Medical Examiner for 37 years. No longer an active pilot, he once held a commercial pilot's license with instrument, multiengine, and CFI ratings.

This article originally appeared in the Federal Air Surgeon's Medical Bulletin, Summer l998.


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