Efficacy of high-intensity aerobic exercise on common multiple sclerosis symptoms

Abstract

Objectives: Fatigue and walking impairment are disabling symptoms of multiple sclerosis (MS). We investigated the effects of progressive aerobic exercise (PAE) on fatigue, walking, cardiorespiratory fitness (VO₂ max), and quality of life in people with MS (pwMS).

Materials & methods: Randomized controlled trial (1:1 ratio, stratified by sex) with a 24-week crossover follow-up and intention-to-treat analysis. Allocation to an exercise (24 weeks of PAE followed by self-guided physical activity) and a waitlist (24 weeks of habitual lifestyle followed by PAE) group. PAE comprised two supervised sessions per week; 30-60 min, 65-95% of maximum heart rate. Fatigue impact (Modified Fatigue Impact Scale; MFIS) and severity (Fatigue Severity Scale; FSS), walking ability (12-item MS Walking Scale; MSWS-12) and capacity (Six-Minute Walk Test; 6MWT, Six Spot Step Test; SSST), quality of life (Short Form 36 health survey; SF-36), and VO₂ max were measured at baseline, 24 weeks, and 48 weeks.

Results: Eighty-six pwMS were enrolled. Following PAE between-group differences showed reductions in MFIS_total (-5.3 [95% CI: -10.9;0.4], point estimate >clinical relevance), MFIS_physical subscore (-2.8 [-5.6;-0.1]), and MFIS_psychosocial subscore (-0.9 [-1.6;-0.2]), and an increase in VO₂ max (+3.5 ml O₂ /min/kg [2.0;5.1]). MSWS-12 (-5.9 [-11.9; 0.2]) and 6MWT (+14 m [-5;33]) differences suggested potential small walking improvements. No changes observed in FSS, SSST, or SF-36.

Conclusions: In a representative sample of pwMS, PAE induced a clinically relevant reduction in fatigue impact, whereas small and no effects were seen for walking and quality of life, respectively. The results need confirmation in a future trial due to the study limitations.

Keywords: aerobic training; exercise therapy; fatigue; rehabilitation.