Americans know exercise is good for them. A proliferation of health clubs and ?tness centers, joggers in every park and walkers in every shopping mall, and constantly changing fashion trends in exercise gear are all evidence that we’ve gotten the message. Ironically, at the same time, advances in technology and labor-saving devices (along with other factors) have made us more sedentary and more overweight.
A sedentary lifestyle is hard on your entire body—muscles, bones, heart, lungs, arteries—because your body is a physical system that is built to move. In terms of cardiovascular bene?t, exercise ?rst strengthens your heart muscle and makes it pump blood more ef?ciently. In your bloodstream, it reduces harmful triglycerides, increases good HDL cho- lesterol, and improves the proportion of HDL to the bad LDL choles- terol. This effect is so important that being physically inactive is a major risk factor—just like smoking, high blood pressure, or high cholesterol levels—for developing coronary artery disease. It doubles your chances of having a heart attack.
At the same time, exercise tends to lower your blood pressure and reduce elevated blood sugar levels if you have diabetes, both of which in turn reduce your risk of heart disease. Of course, exercise also helps you control your weight and reduce obesity. So when you exercise, you are working on your high blood cholesterol, high blood pressure, or diabetes. You are less likely to develop these problems if you are active. Even a moderate increase in physical activity—30 minutes or more of brisk walking most days of the week—is enough to have a signi?cant positive effect on your heart and blood vessels. Exercise can bene?t you, no matter how old you are or what your current ?tness level is.
Exercise also helps you modify the effects of some other factors that are harmful to heart health. It reduces stress, anxiety, and depres- sion and their toll on your body. If you smoke, being active can make it easier to cut down or quit. Exercise never takes the place of other lifestyle changes you need to make to control as many of your risk fac- tors as you can (quitting smoking, eating more healthfully, and so on). However, a major research study in JAMA, the Journal of the American Medical Association, showed that overweight women who exercised had a longer life expectancy than overweight women who were not physically active.