Exercise Regularly to Avoid Having a ‘Silent Stroke’

What’s the difference between a silent stroke and a mini-stroke?  As the name implies, a silent stroke produces no immediate symptoms, but this small vascular lesion, only found by an MRI (magnetic resonance imaging), can result in a higher risk of falls, memory problems impaired mobility, and even dementia.  (A mini-stroke, transient ischemic attack, or TIA, has clear-cut, albeit transient, symptoms.)  It’s been estimated that by the age of 70, roughly 10% of people who are stroke-free have suffered at least one small silent stroke that can be seen on MRI.

Columbia University, NY, researchers decided to examine a possible association between silent stroke and physical exercise in 70-year-old subjects.  They have published the results of their study in Neurology.  There were more than 12,000 participants who were stroke-free at entry; their average age was 70, 60% were women, and 65% were Hispanic.  They all completed a questionnaire about how often and how intensely they exercised; they had a brain MRI on average 6 years after enrollment. 

The participants were classified into 4 groups, or quartiles, according to their level of daily physical activity, measured in metabolic equivalent score (METS).  The MRI exams revealed that 197 (16%) of the participants had evidence of a silent stroke.  Compared with participants who did no physical exercise, those in the upper quartile for activity were almost half as likely to have a silent brain infarct, or silent stroke.  There was no difference between those who did lighter exercise and those who did none.    

An interesting additional finding was that there was no evidence of any difference between high level exercisers and no exercisers in those who had Medicaid or no health insurance.  The former were no less likely to have silent infarcts than those who did no regular exercise.  One of the study authors speculates that ‘overall life difficulties’ lessen the protective effect of regular exercise.

Just because light to moderate exercise had no protective effect compared to intense exercise on the occurrence of silent strokes, there’s no reason for light exercisers to give up.  There are plenty of other conditions where light to moderate exercise has a beneficial effect.