Moderate Exercise May Cut Risk of 'Silent' Stroke

June 8, 2011 -- People who continue to engage in moderate to intense exercise as they age may be less likely to develop the small brain lesions commonly referred to as silent strokes, new research suggests.

Silent strokes are generally not recognized at the time they happen because patients do not have the symptoms associated with major strokes, such as severe headache, dizziness, speech problems, and paralysis.

They occur when small blood vessels in the brain become blocked or rupture and, just like clinically evident strokes, they can lead to long-term issues such as memory problems.

Regular exercise has been shown to protect against major stroke, but the role of physical activity in silent stroke has not been well understood.

Moderate to Intense Exercise vs. Light Exercise

The newly published study by researchers at New York's Columbia University and Florida's University of Miami included roughly 1,200 older people who had no history of stroke at enrollment.

Most of the study participants were in their 60s when they completed a detailed questionnaire exploring how often and intensely they exercised upon entering the study.

Roughly six years later, at an average age of 70, the participant underwent magnetic resonance imaging (MRI) brain scans.

The scans showed that 197 participants, or 16%, had small brain lesions indicative of silent stroke.

People who reported engaging in moderate to intense exercise were 40% less likely to have the lesions than people who did not exercise at all, even after the researchers took into account other stroke risk factors such as high blood pressure and high cholesterol.

Regular light exercise, such as golf, walking, bowling, or dancing did not appear to decrease the risk for silent stroke, but study researcher and stroke specialist Joshua Willey, MD, says these activities clearly benefit health.

Willey is an assistant professor of neurology at Columbia University.

"I would not want these findings to discourage people from walking or performing other light exercise," he tells WebMD. "But it may be that a certain level of exercise frequency and intensity is needed to lower silent stroke risk."

American Heart Association: Get Moving

The American Heart Association (AHA) recommends at least 150 minutes per week of moderate intensity exercise or 75 minutes per week of vigorous activity to lower cardiovascular risk.

Moderate to intense activity can include brisk walking, gardening, housework, swimming, jogging, hiking, biking, and tennis.

AHA spokesman and stroke expert Daniel Lackland, MD, of the Medical University of South Carolina in Charleston, tells WebMD that while exercise is good for the heart and arteries, older people who have been sedentary for years need to be careful.

"You wouldn't tell someone in their 70s or 80s who has not exercised in the past to go out and start jogging," Lackland says. "But just about anybody can start an appropriate medically supervised exercise program at any age."

Willey counsels his stroke patients to discuss the level and type of physical activity that is appropriate for them with their general practitioner or internist before beginning an exercise program.