Walking Just 4 Hours a Week Linked to Reduced Stroke Severity

Damian McNamara

September 19, 2018

Compared with those who are physically inactive, adults who routinely engaged in light to moderate physical activity prior to a stroke or transient ischemic attack were twice as likely to experience a mild event rather than a moderate or severe one, new research suggests.

The retrospective study showed that more than half (52%) of the 925 people in two Swedish stroke registries were physically inactive.

"The focus of previous studies has often been on moderate- or high-intensity exercise, leaving light physical activity unassessed. In this study, both light physical activity as well as exercise were proven to be beneficial," principal investigator Malin Reinholdsson, PT, MS, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg and the Sahlgrenska University Hospital, Sweden, told Medscape Medical News.

The finding that even light physical activity, as recommended by the World Health Organization, can have a positive impact in reducing the severity of a future stroke is both new and surprising, she added.

"We did not anticipate that prestroke light physical activity such as walking or bicycling at least 4 hours per week would have an impact on stroke severity," Reinholdssen said.

The study was published online September 19 in Neurology.

Past Research Inconsistent

Previous research in animals has shown a similar neuroprotective effect with physical activity prior to a stroke. Research in humans, however, has been less consistent. In some studies, physical activity was associated with less severe stroke symptoms, whereas others showed no significant effect.

The current study expands on the evidence linking physical activity to stroke severity and recovery but with "a larger population than most previous studies," Reinholdsson said.

She and her colleagues retrospectively studied the Physical Activity Pre-Stroke Gothenburg population, using data from Riksstroke, the Swedish Stroke Register, and Vastroke, the local stroke register. About 45% of the study cohort were women, the mean age was 73 years, and participants were admitted to Sahlgrenska University Hospital between November 2014 and April 2016.

The majority (80%) had experienced a mild stroke on admission, as determined on the basis of the National Institutes of Health Stroke Scale (NIHSS) score. Ischemic stroke was the most common cerebrovascular event, affecting 93.8% of the cohort; another 5.8% had cerebral hemorrhage; and 0.4% experienced a hemorrhagic or ischemic stroke.

Physical activity levels were self-reported using the Saltin-Grimby Physical Activity Level Scale (SGPALS). Physically inactivity is indicated as 1 on the SGPALS; some physical activity for at least 4 hours a week, considered light physical activity, receives a 2; regular physical activity and training for at least 2 to 3 hours a week, considered moderate physical activity, receives a 3; and regular hard physical training for competition sports several times per week, ie, vigorous physical activity, is rated 4.

Significant Benefits

Stroke was more severe in the physically inactive group than in both the light physical activity group (level 2; P < .001) and the moderate physical activity group (levels 3-4; P < .001) when analyzed with negative binomial regression.

In contrast, the researchers report no significant difference in stroke severity between the light physical activity group (walking or a similar activity for at least 4 hours a week) and the moderate physical activity group (training 2 to 3 hours per week).

"These results presented here suggest that both light and moderate physical activities are beneficial," the authors note.

Potential risk factors, including sex, smoking, and diabetes, as well as protective treatments, such as taking statins or antihypertensive medications, did not influence stroke severity.

"It is important to identify physically inactive patients and to give specific recommendations about physical activities and provide qualified support whenever needed," Reinholdsson said. "Remember to encourage your patients to stay physically active [and to] keep on walking."

Table. Potential Predictors of Mild Acute Stroke Severity*

  Odds Ratio Confidence Interval P Value
Physical activity 2.30 1.64-3.22 < .001
Age 0.97 0.96-0.98 < .001
Smoking 1.27 0.76-2.12 .359
Diabetes 1.04 0.68-1.59 .855
Sex 1.40 1.02-1.93 .040
Statin therapy 0.93 0.62-1.39 .726
Antihypertension treatment 0.69 0.49-0.96 .029
*Based on logistic regression analysis; stroke severity according to NIHSS scores.

 

The logistic regression analysis categorized stroke severity as mild (NIHSS score, 0 to 5) or moderate to severe stroke (score, 6 to 42) on admission. The analysis also controlled for factors including age, sex, smoking, diabetes, and protective treatments, such as statins or antihypertensive medications.

A wide number of clinical variables collected from a large number of patients is a strength of a registry-based study, the authors note. The retrospective design and use of self-reported information, such as employed in the SGPALS instrument, are potential limitations.

Studies to clarify the potential mechanisms by which physical activity modulates stroke severity are warranted, the researchers write. In addition, future research could explore the associations between prestroke physical activity and cognitive function after a stroke, as well as long-term recovery outcomes.

"We want to explore if prestroke physical activity has an impact on cognitive function after stroke when assessed on the stroke unit," Reinholdsson said. "We know that cognition is often impaired after a stroke and is an essential component to become independent in performing daily life activities."

"Important Limitations"

The current study "provides evidence in support of previous literature suggesting that prestroke physical activity favorably influences stroke severity," Nicole L. Spartano, PhD, Section of Endocrinology, Diabetes, Nutrition and Weight Management, Boston University School of Medicine, Massachusetts, and Julie Bernhardt, PhD, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Australia, write in an accompanying editorial.

However, they point to limitations, which were also acknowledged by the authors, including the retrospective design and self-reported prestroke physical activity levels. Recall bias, potential memory deficits associated with stroke, and possible depression in some patients could also have affected the results, they suggest.

"Although the results of the study by Reinholdsson et al are promising, in light of important limitations of the study design and inconsistent evidence from cohort studies, we must view the results of the current study cautiously," they write. "However, these results do add to the growing body of literature suggesting a wide range of health benefits from light physical activity."

The study was funded by the Swedish Research Council, the Local Research and Development Board for Gothenburg and Southern Bohuslän, the Renée Eanders Foundation, the Swedish Stroke Association, the Swedish Heart-Lung Foundation, the Swedish Brain Foundation, and the Promobilia Foundation in Sweden. Dr Reinholdsson has reported no relevant financial relationships. Dr Spartano has received research support from the NIH and American Heart Association. Dr Bernhardt has served on the scientific advisory boards of Dart Neuroscience consultancy, DSMB, and the LEAST observational study; has received funding for travel from the World Federation of Neurorehabilitation, the Danish Physiotherapy Congress, and the Royal Australian College of Physicians meeting; has served on the editorial boards of the International Journal of Stroke, Stroke, and Clinical and Research Innovations; and has received research support from the NHMRC and the Stroke Association UK.

Neurology. Published online September 19, 2018. Full articleEditorial

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