… endurance exercise is the best way to improve cardiovascular function. It helps keep the heart muscle supple and the arteries flexible, lowers the resting heart rate, and boosts the heart's peak ability to deliver oxygen-rich blood to the body's tissues. A related benefit is a fall in blood pressure.

Endurance exercise is also the best way to protect the body's metabolism from the effects of age. It reduces body fat, sensitizes the body's tissues to insulin, and lowers blood sugar levels. Exercise boosts the HDL ("good") cholesterol and lowers levels of LDL ("bad") cholesterol and triglycerides. And the same types of activity will fight some of the neurological and psychologic-al changes of aging. Endurance exercise boosts mood and improves sleep, countering anxiety and depression. In addition, it improves reflex time and helps stave off age-related memory loss. All in all, many of the changes that physiologists attribute to aging are actually caused by disuse …

… The key is regular activity. Start slowly if you are out of shape, then build up gradually to 3–4 hours a week…