Exercise protects against silent stroke: Study

By Dr. Ananya Mandal, MDJun 9 2011

According to a new study older adults who regularly exercise might be less likely to have a “silent stroke” than non-exercisers.

Strokes can cause brain damage by cutting off blood flow to the brain. But unlike major strokes, recognizable by symptoms such as weakness on one side of the body and trouble speaking, so-called silent strokes by definition go unnoticed. Symptoms can include subtle memory and mobility problems, as well as an increased risk for future strokes, according to the American Academy of Neurology. Silent strokes are also different from mini-strokes, which are noticeable but last only for minutes or hours.

This new study from the Columbia University and the University of Miami asked people who hadn’t experienced a stroke about their level of physical activity. The study began in 1993, and involved members of the Northern Manhattan Study cohort that eventually reached 3,298 people over the age of 55. The focus of the analysis was on risk factors for stroke and other vascular conditions. Each study participant was asked to complete a questionnaire about the frequency and intensity of their exercise. The response: 43% weren’t regularly active, 36% did light exercise such as walking or golfing and 21% engaged in moderate to heavy exercise such as jogging, biking and swimming.

Thereafter the researchers looked at MRI scans performed several years later for signs of silent stroke when the participants were on average 70 years old. They found that the moderate-to-heavy exercisers were 40% less likely to have suffered a silent stroke than the non-exercisers. The results were published online Wednesday in the journal Neurology. The researchers found no difference between light and no exercisers in the odds of having a silent stroke.

According to study co-author Joshua Willey a researcher at Columbia University’s Department of Neurology, “It’s not good enough just to exercise, but the more (intense) the better.” Willey explained, “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.”

Authors write, “It is important to note that light-intensity physical activity is likely to have protective effects against multiple other conditions associated with aging and our findings should not discourage individuals from performing even light intensity activities.” The American Stroke Assn. said, “Being inactive, obese or both can increase your risk of high blood pressure, high blood cholesterol, diabetes, heart disease and stroke.” The American Heart Association recommends 150 minutes of moderate-intensity, or 75 minutes of vigorous-intensity exercise weekly, to maintain cardiovascular health.