Dyslipidemia and Exercise

Dyslipidemia Abnormal blood lipid / lipoprotein levels Severe dyslipidemia linked to genetic defects in cholesterol

metabolism Less severe cases

response to other diseases or combining a specific genetic pattern with various environmental exposures (diet, smoking)

Overview of Pathophysiology TG and CHL move b/t the intestine, liver and tissue A variety of environmental, genetic and pathologic factors alter

TG and CHL transport High lipoprotein concentrations may alter pathways

influence CAD risk

Combined these factors are related to elevated lipid levels known as DYSLIPIDEMIA

Overview of Lipoprotein Metabolic Pathways

Lipids Lipids non-soluble in plasma so combines with proteins to form

lipoproteins Chylomicrons: from absorption of dietary triglyceride Very-low-density-Lipoprotein (VLDL): synthesized in the liver, primary

transport mechanism for synthesized triglyceride Low-density-Lipoprotein (LDL): final stage of breakdown VLDL, carier

of cholesterol High-density-Lipoprotein (HDL): involved in reverse transport of

cholesterol

Triglycerides Composed of three fatty acids and a glycerol

molecule Several functions

Membrane structure Eich energy source

9 calories of energy for each fat gram

Found in all cell membranes

Cholesterol Waxy, fat-like substance produced by liver Absorbed by intestine during food digestion

Dietary cholesterol is present in most food derived from animals (not in plants)

Essential to body to build cell membranes, produce sex hormones, form bile acids (necessary for digestion of fats)

Travels thru bloodstream as part of a larger particle called Lipoproteins classified based on thickness or density of the surrounding

protein shell

LDL-”the bad guy” VLDL molecule with most of TriG removed;

all of the chol remains Consumed by the body cells as building blocks for

hormones and cell membranes Excess LDL in blood forms deposits (plaques) on

artery walls which narrows them Susceptible to oxidation by free radicals which

enhances the atherosclerotic process Blood clots as plaques grow leading to atherosclerosis, HD

and heart attacks

HDL-”the good guy” Transports excess cholesterol back to the liver

to be excreted (reverse chol transport) Exists in two main subclasses: HDL2 and

HDL 3

Forms of Dyslipidemia Hypercholesterolemia

elevated blood cholesterol levels Hypertriglyceridemia

elevated triglyceride levels Hyperlipidema

elevated chol and TG Hyperlipoproteinemia

elevated lipoproteins Hypoalphalipoprotein syndrome

low LDL

Causative Factors for Dyslipidemia

Heredity/Genetics Advanced age Gender Smoking Excessive alcohol consumption Fat diet Over fat Certain meds Steroids DM, Hypothyroid Menopause

Video http://www.youtube.com/watch?v=hRx_i9npTDU&feature=related http://www.youtube.com/watch?v=QfaoHAIUy0g http://www.youtube.com/watch?v=R1DAjRixZKg&feature=related http://www.youtube.com/watch?v=-WhADd1GKtA&feature=related

Forms Dyslipidemia: Lipids General term for fat molecules from diet or produced by

the body: either in the form of triglycerides or cholesterol

Required for absorption of fat soluble vitamins (A,D,E,K) Insoluble in blood and must combine with proteins

(lipoproteins) to circulate Excess is harmful and increases risk Some is essential for good health and normal functioning

Cholesterol Guidelines

Diagnostic and Lab Evaluations Identified thru a complete blood lipid profile

following a 12-hr fast Most lab reports will provide: total cholesterol,

HDL, LDL and TG National Cholesterol Education Program (NCEP)

goals for both individual management of CHOL Recommends: adults over 20 have their total chol

measured 1 time every 5 years

Treatments Intensity of treatment depends on patients

overall risk status for disease Diet and exercise-3 to 6 months Pharmacological management-considered an

adjunct to the above

Types of Medications Used Statins-most effective and most commonly used Nicotinic acid-comes with several side effects:

skin irritation/flushing Bile Acid Sequestrants (reduce uptake) Fibric Acids (increase HDL) Probucol-inhibits LDL oxidation Estrogen Replacement Therapy (ERT)

Impact of Statins Powerful effect to lower LDL and raise HDL

by blocking an enzyme needed to produce cholesterol in the liver

Typical improvements: 18-55% decrease in LDL, 5-15% increase in HDL and 7-30% decrease in TG

Statins: Cholesterol Lowering DrugsName Brands Crestor Lipitor* Altacor Zocor* Pravachol Zetia Advicor Mevacor*

Additional Benefits: Improved endothelial

function Decrease vascular

inflammation Decrease potential for

thrombosis Promote plaque

stabilization

Complications HTN-drive LDL particles into the arterial

wall with higher pressures Diabetes makes LDL particles more likely to

stick within the arterial wall Smoking-makes arterial endothelium more

permeable (vulnerable) Metabolic Syndrome

Effects of Exercise on Lipid Metabolism Lowering of TG’s is most consistent effect of acute

and chronic exercise (better skeletal muscle uptake) HDL’s often increased with sustained aerobic exercise

(exp of > 1200 cal/wk) Weight/fat loss is required for significant reductions in

LDL and TCH Total amount of PA is more important than intensity to

induce benefits No conclusive evidence for resistance training impact Improvement in lipid profiles is NOT universal w/ EX

Exercise and PA Guidelines Check with individuals physician (meds and

coexisting conditions) Emphasize aerobic endurance and caloric exp 3-5x/wk for 20-60 min Progress as tolerated to 5-7x/wk for 40-60

min Ex with higher volume and intensity shown to

increase HDL

Ex Rx Guidelines Mode: aerobic large muscle activities Intensity: moderate (40-75% of FC) Frequency: most days of week-volume Duration: as tolerated, the more the better-

can accumulate thru day Total energy expenditure = 1000-1600

kcal/wk

Dyslipidemia: Exercise Prescription Frequency: ≥5 d·wk-1 to maximize caloric

expenditure Intensity: 40% to 75% VO2R or HRR Time: 30 to 60 min·d-1. However, to promote or

maintain weight loss, 50 to 60 min/d-1 or more of daily exercise is recommended. Performance of intermittent exercise of at least 10 minutes in duration to accumulate these duration recommendations is an effective alternative to continuous exercise.

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Dyslipidemia: Exercise Prescription (cont.) Type: the primary mode should be aerobic

physical activities that involve the large muscle groups. As part of a balanced exercise program, resistance training exercise should be incorporated. People with dyslipidemia without comorbidities may follow the resistance training guidelines for healthy adults.