10,000 Steps

It seems that anywhere you turn these days, people are wearing pedometersyou know, those little pagerlike devices that attach to your waistband and count the number of steps you take. In the U.S., the American Diabetes Association has packaged one with its new book on the benefits of physical activity, Small Steps, Big Rewards, and McDonald's offered a free one with its new Happy Meal for adults, which was test-marketed in Indiana last fall.

How many steps should you rack up? The figure you see most often is 10,000 a day. That's a nice, round number, based on...