Starting aerobic exercise just two months after a stroke is safe and may help protect thinking skills, according to new research. The study provides fresh hope for stroke survivors that they can reduce their elevated risk of dementia.
After a stroke, some immediate cognitive decline is to be expected. However, up to one-third of stroke survivors can go on to develop post-stroke dementia, a more progressive and sustained decline in thinking and memory function. One thing that has consistently been shown to improve cognitive functioning is exercise.
A new international study led by Monash University examined the physical effect that two types of exercise – aerobic exercise on one hand, stretching and balance exercises on the other – had on the brain after a stroke, and how they affected cognition.
The research team, which was also from the University of Melbourne, the Florey Institute, the University of British Columbia, and the Australian Catholic University, recruited 107 people who’d survived an ischemic stroke from hospitals in Melbourne, Australia. An ischemic stroke is caused by a blocked blood vessel, which deprives the brain cells of oxygen and nutrients. The other kind of stroke, a hemorrhagic stroke, results from a ruptured blood vessel that leads to bleeding into or around the brain, damaging brain cells. Hemorrhagic strokes are often more severe. The average age of participants was 64.
Participants were divided into two groups. The cardiorespiratory exercise group did eight weeks of aerobic exercise and resistance training, three times a week, each session lasting 60 minutes. The control group did balance and stretching exercises (to ensure that participants thought they were still in an “active” program). They had brain MRI scans at two, four, and 12 months post-stroke, to measure hippocampal and total brain volume. The hippocampus is primarily responsible for memory and learning, and commonly shrinks, or atrophies, after a stroke. The participants also underwent cognitive tests for executive function (that is, self-management) and overall cognitive ability, which includes things like memory, attention, language, and executive function. They were also monitored for safety during exercise.
The researchers found no meaningful difference in hippocampal shrinkage between the exercise and control groups at four months. Both groups showed less shrinkage than expected from previous research, possibly because even balance and stretching produces brain benefits. In terms of cognition, at 12 months, the exercise group performed better on executive function, completing the test task about 3.7 seconds faster on average. The exercise group also scored slightly better on overall cognition tests. Aerobic exercise was deemed safe. No exercise-related deaths or major adverse events were reported.
“Both the cardiorespiratory and balance and stretching control groups lost less brain volume than has been observed in prior studies where no intervention was offered,” said the study’s lead author, Professor Amy Brodtmann, PhD, who leads the Department of Neuroscience’s Cognitive Health Initiative in Monash University’s School of Translational Medicine. “Indeed, their brain volume change was comparable to that seen in stroke-free healthy control participants, suggesting that both interventions may protect the brain.”
The study has some limitations. Principally, only 104 participants completed the trial, which limits the potential to detect subtle effects. Further, the control group wasn’t “inactive” – balance and stretching exercises may themselves improve brain health, making it harder to see differences. Fewer women and highly educated participants were enrolled, limiting the generalizability of the findings. And, while cognitive test scores improved, it’s not certain how meaningful these small differences are in daily life.
Nonetheless, the study suggests that structured aerobic and resistance exercise can be safely offered to stroke survivors as early as two months post-stroke. And it showed promising signs of preserving thinking skills over the first year. It’s hoped that future research will provide even more answers.
“Our very close testing of our participants will allow us to unpack these effects in subsequent papers,” Brodtmann said. “I’m encouraged by the fact that the interventions both seemed to preserve brain volume and cognition.”
It would seem, then, that the broader message for stroke survivors is that any type of exercise, whether it’s aerobic or balance and stretching, may help maintain brain health.
The study was published in the journal JAMA Network Open.
Source: Monash University
