Carbohydrates Part III

Fueling the Athlete

Diabetes

• Recall: – When intensity of exercise goes up, use of

what fuel goes up? Why?– Over time (duration), use of what fuel goes

up? (assuming there’s plenty of oxygen available) Why?

CHO and the Athlete

– Why the concern over Why the concern over CHO?CHO?

–

• CHO is the prime E source for –

–

–

• What types of athletes risk glycogen depletion?– – –

• What happens when an athlete starts to run out of glycogen?

THE TIME TO FATIGUE IS DIRECTLY RELATED TO

INITIAL GLYCOGEN STORES

• So the goals of feeding CHO to these athletes are to – Maximize glycogen stores before the event– Minimize losses during the event– Re-synthesize glycogen after the event

Daily CHO Needs for Athletes:

60% CHO recommended (up to 70% during heavy training)

OR If exercise < 60 minutes per day

5 g/kg (typical Am. Diet = 4 g/kg)

If exercise 60 - 90 minutes/day 6-7 g/kg

If training >90 - 120 minutes/day8 - 10 g/kg

If extreme program (6-8 hours/day - cycling)

10-12 g or more/kg

Pre-Endurance Event:Glycogen Supercompensation

• AKA CHO-loading• For events 90 min. OR intermittent • NOT recommended for those w/ diabetes

or known heart disease• Can nearly double muscle glycogen stores

: day 6 90 min (70-75% VO2max) 60% CHO (nl)

5 40 normal

4 40 normal

3 20 70%

2 20 8-10g/kg males,

6-8g/kg females

1 rest same

race day

• Can be done in 2-3 days, as long as –

–

PRE EVENT MEAL

• Best: Consume 4 hours prior to event

– 4-5 g/kg body weight

Example: 60kg athlete:

• If 4 hrs before event isn’t feasible, consume less 1-

2 hours before the event (1-2g/kg).

– Foods that are easily digested and low in fat/fiber

– Glycemic index?

During Event: Minimizing losses, Maintaining blood glucose levels

• 15 to 20g CHO every 15-20 min. – (or 30-60g CHO per hour of exercise)– – at optimal concentration

• Glycemic index?

Post-Event:Glycogen Repletion: Biphasic

• Rapid initial response – to baseline

• Slower 2° phase: to above normal levels

• Proportional to CHO intake–

–

–

– protein-CHO combination may increase glycogen re-synthesis

• Important for athletes who have events or training sessions within 24-48 hours of activity

• (Repletion usually takes ~ 48h for events lasting >90 minutes. – Can take up to 5 days

Sports Drinks

• 6-8% CHO solution is best (most sports drinks)–

–

• Glucose polymers in sports drinks are quickly absorbed

•

– Optimal post exercise fluids should be high glycemic index fluids (low fructose)

Diabetes Mellitus

Diabetes Mellitus: • A group of metabolic diseases

characterized by hyperglycemia

• Resulting from defects in insulin secretion, insulin action, or both. (ADA Website)

Approximately half the people with diabetes are undiagnosed

Major cause of:–

–

–

–

–

Definitions• FPG: Fasting Plasma Glucose• CPG: Casual Plasma Glucose (non-

fasting)• OGTT: Oral Glucose Tolerance Test

(75g)• Hemoglobin A1c (glycated

hemoglobin, glycosylated hemoglobin) – Indicates average BG levels over approx.

3 months. % of total Hgb attached to glucose

– Normal: 4-6% (DM: >8%)

Diagnosis(don’t memorize - just remember that

having hyperglycemia once is not diagnostic, and can happen for reasons

other than diabetes)

• Pre-Diabetes (new diagnosis) – FPG 100-125mg/dl– OGTT 2h 140-199 mg/dl

• Diabetes– Confirmed FPG 126 mg/dL – CPG 200 mg/dl + symptoms – OGTT (75g glu) 2hPG 200 mg/dl

Type 1 Diabetes

• AKA “juvenile onset diabetes,” or “insulin-dependent diabetes”

•

• Most diagnosed < age 20

• Damage to beta cells of pancreas

• Dependent on exogenous ___________

• Meals timed w/ insulin doses to regulate blood glucose– CHO control

Type 2 Diabetes AKA “adult onset diabetes” or non-

insulin dependent diabetes.

Pancreas produces some insulin, but

Most diagnosed > age 40…

Risk:

gestational diabetes

2

Consequences of Diabetes

• Hyperglycemia

– Dehydration

– Excessive thirst and urination

– Excessive hunger

• Glycosuria (glu spills into urine:

>180mg/dl)

• Ketosis (Type 1) – Cells aren’t receiving glucose/amino

acids due to inadequate or no insulin

– Fat is mobilized for E

– Liver responds (to fat mobilization) by producing ketone bodies

– Accumulate in blood ketoacidosis

– Severe ketoacidosis _________

• Nonketotic Coma (Type2) – coma due to extremely high blood glucose

• Hypoglycemia – too much insulin/mediacations, strenuous activity, inadequate food intake, alcohol intake, etc. Can be life-threatening. – (note: hypoglycemia resembles

intoxication—Type 1 pts should wear ID bracelets)

Symptoms Of Hypoglycemia – Shakiness, dizziness, sweating– Hunger– Headache– Pale skin color – Sudden moodiness or behavior

changes, such as crying for no apparent reason

– Clumsy or jerky movements – Difficulty paying attention, or

confusion – Tingling sensations around the

mouth

Chronic Complications of Diabetes

• Cardiovascular Disease• Microangiopathies (disorders

of capillaries)– Kidneys– Retina

• Neuropathy– loss of sensation in extremities– gangrene amputations

Treatment• Type 1: Diet, exercise, insulin

• Type 2:– Treatment includes weight loss – Meal planning:consistent CHO intake

throughout the day – Medications: Oral hypoglycemic

agents (OHA)– 40% will require exogenous insulin

• Both types:

Effects of Exercise•

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