Exercise and Cardiovascular Disease

Jewish Hospital Cholesterol Center, Charles J. Glueck MD, Director, James E. Lang MD, Associate Director, LeAnn Coberly MD Assistant Medical Director. Jewish Hospital Cholesterol Center, 3200 Burnet Ave, Cincinnati, Ohio 45229.

Phone: 513-585-7800 Fax: 513-585-7950
E-mail: glueckch@healthall.com or cglueck@fuse.net
web: http://www.jewishhospitalcincinnati.com/cholesterol/index.html

Q. Does exercise prevent the development of a heart attack?

A. YES! As far back as 1956, it was observed that conductors on London's two-tiered buses who had to run up the stairs and down from tier to tier to get the patrons' fares had many fewer heart attack events than did drivers who sat in comfortable chairs without any exercise.

Q. How does exercise reduce the risk of heart attack?

A. Exercise has an effect on:

Cholesterol, HDL-cholesterol and triglycerides: Contrary to popular belief, exercise does not lower plasma total cholesterol. Even very high level exercise will not "burn the cholesterol out of the artery wall". Exercise programs increase the level of the good high density lipoprotein cholesterol levels (HDL), and lower the level of triglyceride, another blood fat associated with atherosclerosis.
Obesity: Regular exercise is increasingly regarded as an important component of successful weight loss programs.
Cigarette smoking: Studies in many westernized countries have shown reduced smoking rates with increased leisure time physical activity levels. Presumably, as individuals increase their exercise levels, they are less likely to smoke.
Carbohydrate metabolism: Exercise training increases the body sensitivity to insulin, and as such, allows the body to handle sugar in the blood in a more efficient fashion.
Fibrinolytic activity: In the body, there is a normal mechanism to dissolve the tiny blood clots which we form each day. This mechanism is called fibrinolysis. Performance of moderate intensity exercise results in increased fibrinolytic activity.
High blood pressure: Regular exercise may reduce blood pressure in hypertensive individuals or slow its rise with age in normal individuals.
Maintenance of increase of oxygen supply to the heart: The exercise-trained heart is characterized by reduced oxygen demand and reduced work, both of which are very advantageous.

Q. How much exercise do I have to do in order to obtain the benefits listed above?

A. Based on data from the Multiple Risk Factor Intervention Trial, if men at high risk for heart disease increased their level of physical activity to 60 minutes a day at an intensity corresponding to brisk walking, we estimate that there would be at least a 30% reduction of risk of heart attack.

Q. What is the best exercise?

A. There isn't one "best" exercise. The beneficial effects of exercise are related to three factors:

Frequency is the most important. At least 5 periods of exercise per week, 7 periods are ideal.
Duration is next most important. From 30-45 minutes per session is ideal. This does not need to be continuous. Three 10-minute periods, or two 15-minute periods, are beneficial.
Intensity is last. We recommend a pace which is comfortable, and which you cansustain without any symptoms. Low impact aerobic exercise (walking, swimming, raking leaves) will have the metabolic benefit of raising the HDL cholesterol. It is not necessary or desirable to exercise at a level which leaves you breathless, with symptoms, or with joints hurting. A reasonable, comfortable, sustained pace is enough. You should still be able to carry on a conversation during the exercise.

Q. Should my exercise be supervised by a physician and should I have an exercise tolerance test before I begin exercising?

A. Any person who has had a previous heart attack, stroke, shortness of blood flow to the heart (angina pectoris), coronary artery bypass surgery, or peripheral vascular disease, should have their exercise program designed and supervised by a physician, at least in the beginning. Similarly, individuals with severe hypertension or diabetes requiring a oral hypoglycemic or insulin should also exercise under a doctor's supervision.

For the person without symptoms of heart disease, and in reasonable health, as determined by their physician's evaluation, an exercise electrocardiogram is probably not necessary prior to beginning a prudent exercise program.

Q. What about weight lifting or Nautilus-type exercise?

A. In general, weight lifting, particularly with weights heavy enough to make you grunt with exertion, is not a good way to raise HDL cholesterol, and is contraindicated if you have previous high blood pressure. When you work against weights or fixed resistance, if those weights are quite heavy, or the resistance is severe, then the exercise is anaerobic, which does not raise HDL cholesterol, and which tends to very briefly severely raise blood pressure.

E-mail: glueckch@healthall.com
or cglueck@fuse.net
Fax: 513-585-7950