Over the past twenty years, it has become evident that elevated levels of cholesterol and lipid components are risk factors for cardiovascular disease. Lipid molecules (especially the lipoproteins) are large molecules of fat (cholesterol and tyiglycerides) combined with proteins. Although fat in the body in general performs important functions, such as lining the walls of each cell, and the formation of certain hormones (like testosterone and estrogens), over abundence of these molecules creates its own set of problems.
Types of Lipids
Of the many classes of lipids, it is well established that there are two classes that affect general health, and are affected in turn by exercise. The first group consists of cholesterols that may have adverse affects on the intima (inner lining) of the artery lining, thus creating increased risks for heart and vessel disease. These include: very-low density lipoproteins (VLDLs), low density lipoproteins (LDLs), and triglyderides. VLDL contains tryglyceride, and is a transport and storage form of fat tissue. LDL molecules are the end product of triglyceride metabolism.
High density lipoproteins (HDL), by contrast, has a protective effect against coronary artery disease10,11. HDL particles pick up free cholesterol from cells after esterification of the enzyme lecithin. HDL then transports cholesterol from liver tissue to cells requiring cholesterol or back to the liver for elimination.
The Risk Profile
The National Institutes of Health have produced a risk-statification table that would be of interest to Fitness Therapists, as it may help set guidelines for intensity-dependent workout schedules for persons depending on the severity of their lipid levels. A table is listed below:
|Table 1. Risk Profile for Specific Lipid Concentrations|
|Total Cholesterol||LDL Cholesterol||HDL Cholesterol||Tryglycerides|
(all levels in mg/dl)
The N.C.E.P Guidelines
Whether or not the ingestion of cholesterol (via eggs, high-fat foods, etc.) is the cause of excessive blood levels of choesterol remains controversial. Some persons who eat very little cholesterol-laiden foods have genetically high levels of cholesterol naturally. None the less, the problem of high lipid levels is of enough concern that the US Department of Health and Human Services developed the National Cholesterol Education Program (NCEP) in 1989 to combat the problem in this country. The NCEP recommends a low-saturated fat, low cholestrol diet, with weight loss (when indicated) to control and correct elevated plasma cholestrol levels.
Weight loss is accomplished by a restricted diet, or increase physical activity. Performing more exercise usually increases the levels of HDL. Studies have been performed on athletes and general fitness advocates and most investigations have shown significant changes in the levels of HDL after exercise. It is evident that aerobic conditioning brings about the most significant changes in HDL. Studies are now underway to determine whether or not resistance exercise produces the same types of changes in cholesterol and its sub-components as aerobic training.
The model of exercise programming into a treatment regime for elevated lipid levels would follow a three phase program (such as the cardiac rehabilitation section above). This program should start with an initial phase where supervised training teaches clients the benefits of conditioning and their effects on lipid levels. They will then move to a phase whereby they assume more responsibility for a self-paced program, and the instructor changes in the routine and records outcomes information for medical professionals and payors.
|Phase I||Walking: 10-15 min.||General range of motion:|
|2 sets of 15 reps:|
with light weights
|Light dumb bells||2 sets of 15 reps||Work on improving: |
range of motion and technique each session
|Elastic/rubber tubing||1-2 sets, 5-10 reps|
|Phase II||Increase aerobic activity to 20 min. |
3-4 days per week.
|Light dumb bells||2-3 sets|
8-10 reps each week
|Increase 5 lbs. on the upper body, 10 lbs. on the lower body|
|Supervised: 1-0n-1, moving to self-paced|
|Phase III||Any combination of aerobic machines, or low impact classes||Strength machines exercise,|
|2-4 sets |
|Exercise to a more progressive format Train|
with a partner
Work on perfecting exercise form, strength, and
The key for making changes in lipid levels is adherence to a regular routine for the first phase of conditioning so that significant reductions in lipid levels may be achieved in a 2-3 month period, and these changes can be maintained over long periods of time (years). With a small weight loss, lipid recductions and hypertention will probably decrease, as well.
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8. Lopez, SA, et al. Effect of exercise and physical fitness on serum lipids and lipoproteins. Athersclerosis. 20:1-9, 1974.
9. Summary of the Second Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. JAMA. 269:3015-3023, 1993.
10. Gordon, D.J., Rifkind, B.M. High density lipoprotein: The clinical implications or recent studies. New England Journal of Medicine. 321:1311-16, 1989.
11. Wood, P.D., Stefanick, M.L., Williams, P.T., Haskell, W.L. The effects on plasma lipoproteins of a prudent weight-reducing diet, with or without exercise, in overweight men and women. New England Journal of Medicine. 325:461-66, 1991.