"As the U.S. population is growing older, there is interest now in how we can live so that we improve our functional capacity well into older age, and not just our physical capacity but our mental capacity, and what they're seeing with regard to [mental] function adds to that body of evidence that physical activity may play an important role," says I-Min Lee, MBBS, ScD, associate epidemiologist at Brigham and Women's Hospital and associate professor of medicine at Harvard Medical School in Boston. Lee, who headed the study, commented on the new findings for WebMD.
In a separate study presented at a meeting of the American College of Cardiology, researchers from Cedars Sinai Medical Center in Los Angeles reported that among overweight women undergoing evaluation for possible heart disease, those who rarely or never performed strenuous activities were more likely to have signs of one risk factor for type 2 diabetes and the heart problems related to it. In addition, inactive women also had much higher blood levels of triglycerides, a harmful form of fat, than the active women.
There are several possible explanations for how stretching the legs can also stretch the mind. Studies of mice show that those that run in exercise wheels for a good part of the day develop more nerve connections and healthier nerve cells in the portion of the brain where learning and memory reside than their sedentary littermates.
Exercise also could help improve blood flow in the brain, just as it improves the function of blood vessels supplying the heart.
"We know that physical activity does a number of favorable things in terms of cardiovascular profile and [artery narrowing], less [blood fat], better fitness -- the same things we know are also associated with [mental] function," Yaffe says.
"Some people say it's not exercising by itself," Oscar Lopez, MD, associate professor of neurology and psychiatry at the University of Pittsburgh, tells WebMD. "It's the social activity that goes with exercise. The guy who wakes up in the morning and starts using [an exercise machine] is different from the group where they run and then they have a cup of tea and spend the whole morning together. That type of social support and contact relieves anxiety and could be as important as exercise by itself."