Older people who regularly exercise at moderate to intense levels may have a 40% lower risk of developing brain damage linked to strokes, certain kinds of dementia, and mobility problems.
Research published Wednesday in the journal Neurology says the MRIs of subjects who exercised at higher levels were significantly less likely to show brain damage caused by blocked arteries that interrupt blood flow markers for strokes than people who exercised lightly.
There was no difference between those who engaged in light exercise and those who did not exercise at all.
Until now, studies have shown exercise helps lower blood pressure, bad cholesterol and insulin levels, all risk factors for strokes causing brain damage. Treating those conditions is helpful, but some brain damage is not reversible.
"It's not good enough just to exercise, but the more (intense), the better," says study co-author Joshua Willey, a physician and researcher at Columbia University's Department of Neurology. "The hope is with lower risk of having these events you'd also be at lower risk of dementia or stroke."
The research involves 1,238 participants in a study started in 1993 at Columbia and the University of Miami, and focuses on risk factors for vascular disease.
Participants completed a questionnaire about how often and intensely they exercised at the beginning of the study and then had MRI scans of their brains six years later, when they were an average of 70 years old.
A total of 43% of participants reported that they had no regular exercise; 36% engaged in regular light exercise, such as golf, walking, bowling or dancing; and 21% engaged in regular moderate to intense exercise, such as hiking, tennis, swimming, biking, jogging or racquetball.
The American Heart Association's guidelines for cardiovascular health includes 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity exercise weekly.
"We did not want this to discourage anyone from exercising, even if it's light exercise," Willey says. "The benefits of exercise are proven. We feel that's an integral part of general good health."
More research is needed, says Joseph Boderick, a stroke specialist at the University of Cincinnati who was involved in the study. The research did not look at obesity. One of the major reasons people don't exercise, he says, is because they're obese.
"Maybe the people who exercised less already had some (damage) and were less steady on their feet," he says.
The study did not address why more strenuous exercise appears to be helpful.
Willey, however, said "some of the effects of exercise appear to be related to improving other health conditions that affect the risk of stroke such as hypertension, obesity, high cholesterol and low HDL, diabetes, atherosclerosis (hardening of the arteries) and heart disease.''
He said some other effects might include reducing inflammation, stabilizing atherosclerotic plaques and preventing blood clotting.
To see more of USAToday.com, or to subscribe, go to http://www.usatoday.com
Copyright 2011 USA TODAY, a division of Gannett Co. Inc.