Higher Cardiovascular Fitness May Help Preserve Mobility in MS

New research shows that cardiorespiratory fitness protects against deterioration in gait quality in patients with multiple sclerosis (MS).

Researchers found that lower cardiorespiratory fitness over time predicts increased variability in step time and may represent a biomarker of subtle neuromuscular decline in MS patients.

Cardiorespiratory fitness “may exert neuroprotective effects on the central nervous system,” according to study researcher Syamala Buragadda, neurophysical therapist and PhD Candidate, Memorial University of Newfoundland, St. John’s, Canada.

She reported her research at the 38th Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) 2022.

gear change

The gait is a complicated process that involves the coordination of multiple systems, but the strides are almost always consistent and symmetrical, Buragadda said.

Patients with MS may experience a subtle deterioration in gait quality even without flare-ups. Considering the neuroprotective properties of exercise, a higher level of fitness could prevent brain atrophy and protect against subtle gait changes.

Calculating step time variability is a sensitive method to map changes in gait quality.

Buragadda, along with co-researcher Michelle Ploughman, PhD, also of Memorial University of Newfoundland, assessed step time variability over time in people with MS and examined whether cardiorespiratory fitness predicts step time variability.

They recruited 49 adults with relapsing remitting MS (63% women) and mild disability (Expanded Disability Status Scale [EDSS] score <4; Median 2.0) from MS clinics in Canada. None required walking aids and none had relapsed in the previous 3 months.

Gait quality was assessed on an instrumented walkway and variability was measured as the coefficient of variation in step time. Cardiorespiratory fitness was measured as maximal oxygen uptake (VO2max) during a graded exercise test using recumbent steppers. The tests were carried out at intervals of 2 years.

There were no significant changes in EDSS scores during the study period. However, step time variability increased from 7.3% at baseline to 8.3% at 2 years.

Cardiorespiratory fitness at baseline was significantly correlated with variability in step time 2 years later (P = 0.016) and was a significant predictor of variability in step time at 2 years, accounting for 10% of the variance, Buragadda reported.

Step time variability, measured on an instrumented walkway, could be a biomarker of subtle changes in walking and balance, she said.

The limitations of the study include a convenient sample that may not reflect the diversity of MS. Also, assessments were made at only two time points, and more time points would likely give better predictive power. In addition, the lack of MRI images limits the correlation of structural changes with clinical observations of gait changes.

A buffer against disability?

Valerie Block, physical therapist and adjunct trainer, Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, and UCSF Weill Institute for Neuroscience, who was contacted for comment, said the results of this study are not surprising and are consistent with, what she has subjectively observed in her work.

“In the general population, cardiovascular fitness has a variety of benefits. Depending on what means the person uses to maintain or improve cardiovascular fitness (e.g. running, walking, swimming, etc.), this would have the potential for neuroplastic effects on gait – even in MS and other neurological diseases.” said Block Medscape Medical News.

Also offering perspective, Brain Sandroff, PhD, Senior Research Scientist, Kessler Foundation, West Orange, NJ said the study provides “more evidence of the multi-systemic benefits of exercise training and better physical fitness in people with MS.”

“The evidence seems to be consolidating more and more as research groups from countries and continents report on similar issues,” Sandroff said.

He noted that the results of this study are consistent with some other data showing that premorbid physical activity is associated with a decrease in mobility over time in people with MS.

“Overall, the data suggest that engaging in physical training early in the disease (or better cardiorespiratory fitness at diagnosis) may provide a buffer against disability progression over time,” Sandroff said Medscape Medical News.

He said it would be interesting to see if “physical fitness/pre-morbid physical activity provides such a buffer in those who already exhibit mobility issues.”

The study had no specific funding. Buragadda, Plowman, Block and Sandroff have disclosed no relevant financial relationships.

38th Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) 2022: Abstract O076. Presented on October 27, 2022.

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