We have known for ages that exercise reduces the risk of stroke, but this risk is not eliminated altogether especially if other risk factors such as high blood pressure and cigarette smoking are not addressed.
A study published in this week’s Neurology adds a new twist to the story. In the new study, Lars-Henrik Krarup and colleagues at Copenhagen University Hospital found that in a cohort of elderly stroke patients, those who had exercised more vigorously before the event had a better prognosis than those who exercised less vigorously or not at all.
Krarup’s group stratified 295 patients that had recently sustained an ischemic stroke into quartiles based on their prestroke physical activity as determined by a questionnaire. They assessed initial stroke severity using the Scandinavian Stroke Scale and 2-year stroke outcomes using the Rankin Scale.
The scientists found a linear relationship such that for each successive increase in prestroke physical activity, initial stroke severity decreased. The most active group was 2.54 times more likely to incur a mild initial stroke than the least active group. These benefits were maintained after two years, in that the most active group was far less likely to experience marked disability.
Krarup’s group suggested that the benefits of exercise might be mediated by release of nitric oxide synthase by cells in the brain’s circulatory system, a phenomenon shown to reduce damaged brain tissue in experimental models of stroke. Krarup’s findings need to be validated in a more diverse group of stroke patients but in the meantime we have yet another reason to be active and physically fit.