Older people who are the most physically active experience less brain shrinkage (a process linked to cognitive decline and dementia) and fewer other signs of aging in the brain than their sedentary counterparts, according to a study of 638 people in their 70s, published in Neurology. In contrast, MRIs revealed that participating in mental or social activities did not affect brain size.
A multi-nation European study of 639 people over 65, published in the journal Stroke, found that exercise was associated with a 40 percent reduction in the risk of cognitive impairment and a 60 percent decrease in vascular-related dementia (such as that resulting from a stroke).
In a large study from the University of North Carolina at Chapel Hill, women who reported exercising regularly (in the past or present) had a reduced risk of developing the disease. But maintaining a healthy weight is also essential, the study found, since substantial weight gain, especially after menopause, nearly wiped out the exercise benefit. A 2009 review of research on exercise and breast cancer prevention concluded that the evidence is “compelling."
Physical activity can add years to people’s lives, according to an analysis from the National Cancer Institute in PLOS Medicine, which included data on 650,000 people in six long-term studies and controlled for other factors that affect longevity. Those who exercised moderately (for instance, walking briskly 150 minutes a week) lived about four years longer, on average, than their sedentary counterparts. Even those who did modest amounts of exercise (such as 75 minutes of walking a week) lived nearly two years longer. And the benefit was seen in the obese as well as in thinner people.