Exercise Tied to 50% Reduction in Mortality
After Stroke

Rosalind Stefanac

August 12, 2021

In a large study of community-based stroke survivors in Canada, researchers found those meeting guideline-recommended levels of physical activity had a significantly lower risk for death from any cause, with a greater than 50% reduction in risk.

Lead study author Raed A. Joundi, MD, DPhil, of the University of Calgary in Alberta, Canada, said he expected results to show exercise was beneficial, but was surprised by the magnitude of the association between physical activity and lower mortality risk.

The impact of physical activity also differed significantly by age; those younger than 75 had a 79% reduction in mortality risk compared with 32% in those age 75 and older.

"This is even after adjusting for factors such heart disease, respiratory conditions, smoking and other functional limitations," said Joundi.

The study was published online August 11 in the journal Neurology.

For this analysis, the researchers used data on a cohort of people across Canada (excluding the province of Quebec) over 3 to 9 years. The 895 patients with prior stroke averaged 72 years of age, while the 97,805 in the control group had an average age of 63.

Weekly physical activity averages were evaluated using the self-reporting Canadian Community Health Survey, which was linked with administrative databases to evaluate the association of physical activity with long-term risk for mortality among stroke survivors compared with controls.

Physical activity was measured in metabolic equivalents (METs); meeting minimum physical activity guidelines was defined as 10 MET-hours/week.

During the study period, more stroke patients than controls died (24.7% vs 5.7%). However, those who met the physical activity guideline recommendations of 10 MET-hours/week had a lower mortality, both in the stroke survivor group (14.6% vs 33.2%; adjusted hazard ratio, 0.46; 95% CI, 0.29 - 0.73) and among control participants (3.6% vs 7.9%; aHR 0.69; 95% CI, 0.62 - 0.76).  

The largest absolute and relative reduction in mortality was among stroke respondents younger than 75 (10.5% vs 29%; aHR, 0.21; 95% CI, 0.10 - 0.43), the researchers note.

There was a significant interaction with age for the stroke patients but not the control group.

"The greatest reduction in mortality was seen between 0 and 10 METs per week…so the main point is that something is better than nothing," said Joundi.

Exercise Guidelines for the Future

Although current guidelines recommend physical activity in stroke survivors, investigators noted that these are largely based on studies in the general population. Therefore, the aim of this research was to get a better understanding of the role of physical activity in the health of stroke survivors in the community, which could ultimately be used to design improved public health campaigns and physical activity interventions.

Given that this is a large study of stroke survivors in the community, Joundi hopes the results will influence future activity guidelines for those who have suffered a stroke.

"We found a log-linear relationship between physical activity and mortality such that 10 MET-hours/week was associated with large reductions in mortality with most benefit achieved by 20 MET-hours/week," the authors concluded. "These thresholds could be considered for use in future guidelines for stroke."

Clinical trials are underway to provide evidence for the implementation of exercise programs after stroke, they add, and offering physical activity programs to stroke survivors in the community "is an increasing priority in the US, Canada, and Europe."

"People are at higher risk of death early on after a stroke but also months and years later, so if we can identify a relatively low-cost and easy intervention like physical activity to improve health and reduce the risk of death for stroke survivors it would be important," Joundi said.

Key Barriers

Paul George, MD, PhD, a stroke and vascular neurologist at Stanford University in California, said findings such as these further strengthen the argument that physical exercise is important after stroke.

"Because the study looked specifically at stroke patients, it can provide further guidance on physical activity recommendations that we provide to our patients following stroke," said George, who was not associated with the study. 

Going forward, he said more research is needed to identify specifically what is preventing stroke patients from exercising more. What is required, he said, is "future research to determine the key barriers to physical activity following stroke and methods to reduce these will also be important to increasing physical activity in stroke survivors."

Joundi said determining how to tailor exercise recommendations to meet the wide range of capabilities of stroke survivors will be another key factor.

"Stroke survivors may have some disabilities, so we need to be able to engage them at an [exercise] level that's possible for them," he said.

The study did not include stroke survivors living in long-term care homes.

The study had no targeted funding. Co-author Eric E. Smith, MD, MPH, reports royalties from UpToDate, and consulting fees from Alnylam, Biogen, and Javelin. Joundi and the other co-authors have disclosed no relevant financial relationships.

Neurol. Published online August 11, 2021. Abstract

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