Exercise Could Protect Against Stroke

Mice that exercised showed increased brain plasticity compared with those that did not.

Findings from a recent animal study suggest that voluntary physical exercise could prevent brain damage resulting from a stroke.

The study showed that mice with access to a running wheel maintained ocular dominance plasticity after a stroke compared with mice that did not have access. These findings could provide a simple method to prevent brain damage in individuals who are at high-risk of experiencing a stroke, or rehabilitate patients who have already experienced one, according to the study published by Frontiers in Aging Neuroscience.

After a stroke, patients can be left with paralysis, speech problems, and memory loss that could be very severe, depending on the location and amount of resulting damaged brain tissue. Recovering from a stroke can be difficult as well, since it depends on the brain’s ability to reorganize itself.

Gaining a better understanding about what can be done to improve healing is a crucial component of devising the optimal rehabilitation plans for these patients.

Voluntary physical activity is known to positively effect a person’s health, can delay memory loss, improve cognitive ability. Researchers have recently discovered that it may also hold the key to better rehabilitation after a stroke, according to the study.

"Our study suggests that physical exercise can be used as a preventive, as well as a therapeutic approach to aid recovery after a cortical stroke," said lead researcher Evgenia Kalogeraki, PhD.

Previous research from these investigators indicated that mice with access to a running wheel have cognitive and social stimulation, and have a more youthful brain into adulthood. In the current study, researchers aimed to determine whether physical exercise alone could elicit these benefits, as well as protect and rehabilitate the brain after a stroke.

The investigators determined the plasticity of the brain in mice models through the use of standard tests that determine the way the brain reacts to a certain experience. For example, when the visual input of 1 eye is diminished for a certain period of time, the brain becomes preferentially activated by the other eye.

The brain’s capability to change eye dominance (ocular dominance plasticity) is related to age, with it being most pronounced in younger animals, and absent in older mice who did not experience this stimulation, according to the study.

The researchers discovered older mice that engaged in physical activity were able to change eye dominance compared with mice that did not exercise. Mice that had free access to a running wheel were also able to preserve their ocular dominance plasticity after a stroke compared with those that did not.

"We found that mice with free access to a running wheel throughout their life preserved a more juvenile brain into adulthood and were able to prevent the negative effects of a stroke," Dr Kalogeraki said.

Additionally, the researchers discovered that exercise could also be used as a rehabilitative method after stroke.

"We also found that mice with no previous access to a running wheel showed an equally positive recovery if voluntary exercise started after a stroke had occurred," said co-author of the study Justyna Pielecka-Fortuna, PhD.

These findings suggest that voluntary physical activity could provide an easy method to prevent strokes or rehabilitate those who have experienced one. Interestingly, these findings have reinforced the benefits of exercise, and have caused lifestyle changes among some of the researchers.

"The fact that the brain can restore its youthfulness by starting physical exercise after a stroke has occurred suggests that it is never too late to benefit from exercise," said first author Siegrid Löwel, PhD. "I've started cycling again -- what is good for the mice cannot be bad for me!"

The investigators hope that these new findings will increase knowledge of how exercise can benefit the brain.

"We now hope to study the mechanisms underlying exercise-mediated activity changes in the brain, to ultimately better guide studies in humans" Dr Kalogeraki concluded.