Is High-Intensity Interval Training More Effective Than Moderate Continuous Training in Rehabilitation of Multiple Sclerosis: A Comprehensive Systematic Review and Meta-analysis

The present study aimed to conduct meta-analysis to determine whether the high intensity interval training (HIIT) protocol is more beneficial in improving outcome measures compared to moderate continuous training (MCT) in people with multiple sclerosis (PwMS). It also aimed to systematically review the exercise protocols differences. A search strategy, locating HIIT in PwMS, was executed in six databases, PubMed, EMBASE, Web of Science, Central Cochrane, Pedro, and Ovid MEDLine. Randomized control trials of HIIT utilizing cycle ergometer or recumbent stepper as exercise modalities were included in analysis. Intervention arms should include at least two intervention arms, including HIIT in one arm, and MCT in the other group. Data extracted from each study includes the following items: basic details of the study (such as author, date of publication, location, and study design), participant characteristics (sample size, mean age, sex, mean disease duration, and extended disability status scale), specifications of the HITT protocol (exercise modality, session duration, number of intervals/session, interval intensity, recovery intensity, recovery interval, and adverse effect), as well as primary outcomes at baseline and post-intervention (cardiorespiratory fitness, fatigue, body composition, cognitive functions, and blood biomarkers). 22 studies included in the systematic review, 11 were included in random effects model pooled analysis. There was a significant effect in favor of HIIT for VO2max of cardiorespiratory functions compared to MCT (ES=0.45 95%, CI [0.14, 0.76], P=.004), and for memory domain of cognitive functions (ES=0.34 95% CI [0.05, 0.63], P=.02). Statistical significance was not achieved for the other variables. HIIT and MCT yield similar results in terms of fatigue, body composition, cognitive functions, and blood biomarkers. However, VO2max of cardiorespiratory functions and memory domain of cognitive functions were in favor of HIIT protocol.