You probably already know that your cholesterol levels are important to keep under control to lower your risk for heart disease, and that a combination of genetics and lifestyle determine these important cholesterol levels. What is a little less clear is the effect exercise has on the cholesterol levels independent of diet and genetics, what type of exercise is best and why exercise is important.
Somewhere between 70-80% of the cholesterol in the body is produced in the liver and not derived from a dietary source. In fact, people on zero cholesterol (i.e. vegan) diets may still have elevated cholesterol levels due to overproduction in the liver. Genetics accounts for our baseline cholesterol levels and determines whether our cholesterol production is dysfunctional. The rest is left to environmental factors, some of which we can control and therefore where we should focus our efforts. Diet, weight, exercise and smoking status all play a role in cholesterol values. All are important, but this article seeks to illuminate the relationship between exercise and cholesterol.
It is clear that exercise can help maintain an appropriate body weight, which in turn helps keep cholesterol levels under control. Extra body fat (especially in the abdominal cavity) leads to increases in low-density lipoproteins (LDL) cholesterol and total cholesterol. But there is more to the exercise and cholesterol link than simply weight.
The first studies on cholesterol values and lifestyle did not separate diet and exercise so it was unclear if the effect of exercise alone on cholesterol was significant. Recent studies have teased out the exercise component and have discovered that exercise works to improve cholesterol by several mechanisms. First, exercise increases the enzymes in the blood stream that remove LDL cholesterol from the blood (where it is dangerous for the heart and blood vessels) and store it in the liver where it is turned to bile or excreted if it is not needed. Second, exercise increases the size of the cholesterol carrying proteins. This is significant because the small lipoproteins can get to places where they can cause damage while the larger ones cannot. And third, exercise has been found to raise the high-density lipoproteins, which have been inversely related to cardiovascular disease and low ratios of total/HDL cholesterol have been linked to lowered heart disease risk. For these reasons, HDL cholesterol is referred to as “good” cholesterol. Less “bad” and more “good” cholesterol levels by exercising seem pretty straightforward, but how much and what type of exercise should be done to get these benefits? There is no concrete answer to that, but the most positive changes have been found in those who exercise vigorously and regularly (30 minutes a day), the more the better within reason.
1.Exercise To Lower Cholesterol, By Susan Davis, Cynthia Dennison Haines, MD. www.webmd
2. Amrican College of Sports Medicine. 1998. ACSM’s Resource Manual for Guidelines for Exercise Testing and Prescription, Third edition. Baltimore: Lippincott Williams and Wilkins.
3. Durstine J.L. & W.L. Haskell. 1994. “Effects of exercise training on plasma lipids and lipoproteins”. Exercise and Sports Science Reviews. 22:477-522.
4. Brownell K.D., P.S. Bachorik & R.S. Ayerle. 1982. “Changes in plasma lipid and lipoprotein levels in men and women after a program of moderate exercise”. Circulation. 65(3):477-84.