Fit Body, Fit Mind?; July/August 2009; Scientific American Mind; by Christopher Hertzog; Arthur F. Kramer; Robert S. Wilson; Ulman Lindenberger; 8 Page(s)

As everybody knows, if you do not work out, your muscles get flaccid. What most people don't realize, however, is that your brain also stays in better shape when you exercise. And not just challenging your noggin by, for example, learning a new language, doing difficult crosswords or taking on other intellectually stimulating tasks. As researchers are finding, physical exercise is critical to vigorous mental health, too.

Surprised? Although the idea of exercising cognitive machinery by performing mentally demanding activities—popularly termed the "use it or lose it" hypothesis—is better known, a review of dozens of studies shows that maintaining a mental edge requires more than that. Other things you do—including participating in activities that make you think, getting regular exercise, staying socially engaged and even having a positive attitude—have a meaningful influence on how effective your cognitive functioning will be in old age.