Better cardiovascular fitness may help preserve mobility in MS

Cardiorespiratory fitness protects against declining gait quality in patients with multiple sclerosis (MS), new research shows.

The researchers found that over time, lower cardiorespiratory fitness predicts increased variability in stride time and may represent a biomarker of subtle neuromuscular decline in MS patients.

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

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

Gait changes

Walking is a complicated process involving the coordination of multiple systems, but the steps are almost always consistent and symmetrical, Buragadda said.

MS patients may experience subtle declines in gait quality even without relapses. Given the neuroprotective properties of exercise, having higher fitness levels could prevent brain atrophy and protect against subtle changes in gait.

Calculation of stride time variability is a sensitive method for mapping changes in gait quality.

Buragadda, with co-investigator Michelle Plowman, PhD, also from Memorial University of Newfoundland, assessed stride time variability over time in people with MS and explored whether cardiorespiratory fitness predicts stride time variability.

They recruited 49 adults with relapsing-remitting MS (63% women) with mild disability (Expanded Disability Status Scale [EDSS] rating <4; median, 2.0) of MS clinics in Canada. None required walking aids and none had experienced a relapse in the previous 3 months.

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

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

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

Stride time variability, measured on an instrumented footbridge, could be a biomarker of subtle changes in gait and balance, she said.

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

A buffer against disability?

Contacted for comment, Valerie Block, physical therapist and assistant instructor, Department of Physical Therapy and Rehabilitation Sciences, University of California, San Francisco, and UCSF Weill Institute for Neuroscience, said the results of this study are not surprising and consistent. to what she has observed, subjectively, in her work.

“In the general population, cardiovascular fitness has a wide range of benefits. Depending on the means the person uses to maintain or improve their cardiovascular fitness (i.e. running, walking, swimming, etc.), this may have neuroplastic effects on gait ― even in MS and other neurological disorders,” Block said. Medscape Medical News.

Also offering perspective, Brain Sandroff, PhD, Principal Investigator, Kessler Foundation, West Orange, New Jersey, said the study provides “more evidence on the multisystem benefits of exercise training and improved physical fitness in people with MS”.

“The evidence seems to be converging more and more on this, as research groups across countries and continents report on similar themes,” Sandroff said.

He noted that the results of this study coincide with other data which has shown that premorbid physical activity is associated with a decline in reduced mobility over time in people with MS.

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

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

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

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

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