Results of studies have been inconsistent concerning the effect of exercise on total cholesterol and LDL cholesterol. But the evidence is stronger that an exercise program can raise HDL cholesterol, and evidence for its effect on lowering the risk of CAD is overwhelming. Exercise helps control your weight; it improves your cardiovascular fitness; it can lower or prevent high blood pressure; and it can improve your body’s response to insulin (thus helping to prevent or manage type 2 diabetes). It can also reduce blood levels of C-reactive protein.
A lack of physical activity, on the other hand, is one of the major risk factors for cardiovascular disease. About three out of four Americans are mostly or totally sedentary, and for them the greatest health boost comes from simply getting up and becoming active.
Current recommendations. For cardiovascular benefits, guidelines from the American College of Sports Medicine and the American Heart Association recommend that, as a minimum, adults get 30 minutes of moderate-intensity aerobic exercise five days a week. Your exercise can be done all at once or in briefer 10-minute periods, as long as the activity is performed at moderate intensity—the equivalent of walking at a pace of three to four miles per hour. Working out more will increase the benefits. If you are exercising to lose weight or maintain weight loss, you should do 60 to 90 minutes of daily activity. (And of course, you must also control your calorie intake.)
As an alternative to moderate-intensity 30-minute workouts, you can do more intense workouts (such as running, basketball or singles tennis) for at least 20 minutes three times a week. The optimal intensity will depend on your age and physical condition.
Even if you cannot meet these guidelines, any amount of exercise, of any intensity, is better than none. Some studies have found that, for sedentary people, exercise doesn’t have to be strenuous to be beneficial—walking a mile or two several times a week can improve fitness somewhat.
Before you begin to exercise. If you are a healthy but sedentary woman over age 50 or man over 40, the American College of Sports Medicine recommends that you consult your physician before beginning a program of regular exercise. If you are 35 or older, consult a physician first if you have any risk factors for heart disease—such as recurrent chest pain, elevated blood cholesterol, high blood pressure, diabetes, obesity or smoking. Whatever your age, contact your physician before beginning even moderate physical activity if you have cardiovascular or lung disease.