From the article “Healthy Aging, With Nary a Supplement” New York Times, Health section…
By JANE E. BRODY

The single most effective activity, studies have found, is an aerobic activity like brisk walking — about 30 minutes a day. If you can’t get out of the house, walk inside. Go up and down stairs, walk the hall, walk from room to room, walk in place. If walking doesn’t suit you, try dancing to music.

In a 2006 study of people aged 60 to 79, those who were assigned to walk briskly three days a week for 45 minutes a day experienced an increase in the brain’s volume, especially in regions involved in memory, planning and multitasking.

Even people already afflicted with chronic ailments — heart or lung disease, arthritis, diabetes, depression, early dementia — can reap significant health benefits from exercise, studies have found.

Americans have yet to learn what Hippocrates, the father of medicine, recognized in 400 B.C. “All parts of the body which have a function if used in moderation and exercised in labors in which each is accustomed, become thereby healthy, well developed and age more slowly; but if unused and left idle they become liable to disease, defective in growth and age quickly.”

So get off the couch and make this year the year you discover the joys and benefits of movement.