Older people who regularly exercise at moderate to intense levels may have a 40% lower risk of developing brain damage linked to ischemic strokes, certain kinds of dementia and mobility problems.
New research published Wednesday in the journal Neurology says the MRIs of people who exercised at higher levels were significantly less likely to show silent brain infarcts — caused by blocked arteries that interrupt blood flow and are markers for strokes — than people who exercised lightly.
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 often brain damage from multiple infarctions is not reversible.
"It's not good enough just to exercise, but the more (intense) the better," says physician Joshua Willey, a co-author of the study and researcher at Columbia University's Department of Neurology. "We think exercise is protecting against the development of brain infarcts, and 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 University and the University of Miami and focuses on risk factors for vascular disease.
Participants completed a questionnaire about how often and how 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.
Forty-three percent 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. There was no difference between those who engaged in light exercise and those who did not exercise.
The American Heart Association's guidelines for ideal cardiovascular health includes 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity exercise a week.
"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 not associated with 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 infarcts and were less steady on their feet," he says.
The study did not address why more strenuous exercise appears to be helpful. Willey, however, says, "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."