Effects of aerobic, resistance, and combined exercise training on health-related quality of life in multiple sclerosis: Systematic review and meta-analysis

•Exercise is effective for improving overall HRQOL in MS.•The effect is greater in the physical domain compared to the mental domain of HRQOL.•The effect is heavily influenced by exercise parameters.•Future studies should examine social support in exercise training for MS. Multiple sclerosis (MS) is an immune-mediated, neurodegenerative disease of the central nervous system that manifests in symptoms that compromise health-related quality of life (HRQOL). HRQOL focuses on a person's overall, subjective evaluation of health status primarily in the physical and mental domains. Exercise training is a form of rehabilitation for managing MS-related outcomes that might influence HRQOL. Reviews on exercise training are available, but we are unaware of a recent comprehensive review and meta-analysis of exercise effects for improving physical and mental domains of HRQOL. This analysis provides an updated review and meta-analysis of randomized controlled trials (RCTs) examining interventions consisting of aerobic, resistance and combined exercise training for improving HRQOL in persons with MS. This systematic review 1) assessed the overall strength of evidence for exercise interventions on HRQOL, 2) evaluated the relative effect of exercise interventions on physical and mental domains of HRQOL, and 3) determined moderators of exercise intervention effects on HRQOL. Seven databases were searched for RCTs evaluating physical and/or mental domains of HRQOL with adults diagnosed with MS and undergoing an intervention of aerobic, resistance or combined exercise training compared with a non-exercise comparator. Data extraction included participant and intervention characteristics, and pre- and post-intervention HRQOL outcome data. Effect sizes (ESs) were calculated as standardized mean differences (SMDs) and a multilevel random-effects model was used to generate an aggregated SMD that compared exercise with non-exercise control conditions. Twelve RCTs met the inclusion criteria and yielded 23 ESs to be analyzed. Participants (N = 593; 308 intervention vs. 285 control conditions) had a mean (±standard deviation) age of 42.4 (6.5) years and 80% (18.3%) were female. Results generated a medium effect of exercise for improving overall HRQOL (ES=0.64, p = 0.0001) with high heterogeneity (Q11=58.8, I2=86.7%). Exercise training yielded a large effect on the physical domain (k = 12, ES=0.82, p