We all know we should exercise. But few realize that being physically active is the single most important thing that most of us can do to improve or maintain our health. Regular movement not only lowers the risk of developing or dying from heart disease, stroke and diabetes, it also prevents certain cancers, improves mood, builds bones, strengthens muscles, expands lung capacity, reduces the risk of falls and fractures, and helps to keep excess weight in check. And those are just some of the more familiar effects.
An explosion in research over the past few years has extended those observations even further. Among other things, exercise appears to boost brainpower—specifically the ability to carry out tasks that require attention, organization and planning, reduce symptoms of depression and anxiety in some people, and enhance the immune system's ability to detect and fend off certain types of cancer. In addition, researchers are moving beyond describing the gross health benefits of regular physical movement to detailing the positive changes that occur at the level of cells and molecules for specific conditions such as atherosclerosis and diabetes.