High-Intensity Interval Training Effects on People With Multiple Sclerosis: A Systematic Review and Meta-analyses for Exercise Capacity and Fatigue.

People with multiple sclerosis often deal with fatigue and reduced exercise capacity, and clinicians have looked for exercise approaches that might help with both. This systematic review and meta-analysis pulled together randomized controlled trials testing high-intensity interval training, short bursts of vigorous effort alternated with recovery periods, against other approaches or no intervention, to see whether it improved exercise capacity and reduced fatigue. Across the pooled data, high-intensity interval training was associated with a statistically significant, though modest, improvement in exercise capacity and a statistically significant reduction in fatigue. The authors describe the overall risk of bias as generally low and methodological quality as good.

Still, the meta-analysis combined only seven trials, so the size and consistency of the benefit remain modest and the evidence base is relatively small for drawing firm conclusions about this population.

If you live with multiple sclerosis, tiredness and reduced stamina for physical activity can be some of the most frustrating parts of the condition. Researchers wanted to know whether a specific style of exercise, high-intensity interval training, which mixes short bursts of hard effort with recovery periods, could help with these two issues. Looking across several small randomized trials, the combined results showed a statistically significant link between this type of training and better exercise capacity, along with a statistically significant reduction in fatigue.

Both effects were modest in size rather than dramatic. It's encouraging that a structured exercise approach showed this pattern, but the evidence comes from a limited number of trials, so these findings give a general signal rather than a guarantee of how any one person would respond. The review doesn't tell us about long-term safety or which specific interval protocols work best.

This is a summary of research, not medical advice. Talk to your own healthcare provider about anything affecting your care.

This review speaks to a question many physiotherapists encounter when planning exercise programs for people with multiple sclerosis: does high-intensity interval training offer measurable benefit for exercise capacity and fatigue compared with other approaches, and how confident can we be in that effect. The systematic review identified eleven randomized controlled trials, with seven contributing to the meta-analysis, and reported generally low risk of bias and good methodological quality across the included studies. The pooled results showed a statistically significant improvement in exercise capacity (standardized mean difference = 0.29, 95% CI 0.05 to 0.53, P = 0.02) and a statistically significant reduction in fatigue (standardized mean difference = -0.26, 95% CI -0.50 to -0.02, P = 0.03).

These effect sizes are small to modest, which should temper expectations about the magnitude of clinical benefit even though the direction of effect is consistent across the two outcomes. What this does not establish is which specific interval protocols, intensities, or durations drive these effects, nor does it address long-term adherence, disease subtype differences, or adverse events, as the abstract does not report safety data. With only seven trials pooled, the evidence base remains limited, and the findings should inform rather than dictate program design decisions for this population.