In previous articles, we’ve talked about the bad cholesterol, and we’ve talked about the good cholesterol. Now, we’ll talk about how important exercise is to your cholesterol levels.

Approximately 107 million American adults have abnormal levels of blood lipids (called cholesterol and triglycerides), representing one of the major risk factors for heart disease. Excess cholesterol builds up inside the walls of the arteries, resulting in the arteries becoming narrow and impairing blood flow. When blood flow is impaired in the heart muscle, the result is a heart attack.

Lipoproteins are the carriers of blood lipids. Some lipoproteins contribute to heart and blood vessel disease (low-density lipoproteins). Some help to prevent it. We have been talking about these preventive or “healthy” cholesterol carriers, called high-density lipoproteins (HDL). These HDL carriers are involved in reverse cholesterol transport. That is, they keep cholesterol from building up in the arteries and can actually reverse the plaque formation in arterial walls. Therefore, raising the HDL reduces the risk of heart and blood vessel disease.

It has been known for a long time that physical inactivity is a risk factor for heart disease. In contrast, exercise has long been advocated as a lifestyle practice to reduce heart disease. But how does exercise effect blood lipids? There is a lot of research examining how exercise influences the levels of lipids in the blood.

The lowering of triglyceride levels is the most consistent effect of exercise on blood lipids. Triglycerides are used as energy by skeletal muscles, resulting in a lowering effect during acute exercise and sustained aerobic exercise training.

Physical activity also has the effect of raising the “healthy” cholesterol (HDL). This effect is not as easily attained as the effect on triglycerides. In order to raise the levels of HDL, aerobic exercise is required. Aerobic exercise is defined as exercise of moderate intensity and relatively longer duration. In raising HDL, the total amount of physical activity seems to be more important than the intensity of the activity.

Greater increases in HDL occur with sustained aerobic exercise. For example, five 30-minute sessions per week would produce a greater increase as compared to three 60-minute sessions. Studies recommend briskly walking or jogging at a moderate pace with the goal of approximately 12 to 18 miles per week.

The greatest increases in HDL occur in individuals with lower initial levels of HDL. Older people and/or those with a more sedentary lifestyle also experience the greatest increases in HDL from aerobic exercise. For example, when healthy, sedentary persons engage in regular aerobic exercise, the HDL levels may increase by 3 to 9 percent. This percent increase greatly reduces the risk for heart disease.

In some individuals, genetic inheritance can influence the response of blood lipids to exercise. Abnormal levels may persist even after aerobic exercise interventions. In these cases, it may be necessary to use medications to modify the blood lipids to recommended levels.

Of course, before a person begins an exercise program, it is recommended that they consult with their physician. Some physicians may want to do a treadmill stress test to help determine your state of fitness or cardiac health.

Although results of studies demonstrate an improvement in HDL from exercise, researchers add that aerobic exercise alone may not be sufficient to bring blood lipids to healthy levels. It is highly recommended that, in addition to aerobic exercise, additional lifestyle interventions such as a heart healthy diet are necessary.

Keep reminding yourself, whenever possible, exercise!