Long-term endurance exercise improves aerobic capacity in patients with relapsing–remitting Multiple Sclerosis: Impact of baseline fatigue

Abstract

Little is known about the sustainability of exercise effects in patients with relapsing–remitting Multiple Sclerosis (RRMS). We present the results of a prospective, observer-blinded, single-center case control study using a “pre–post” design including 89 ambulatory patients with RRMS and an EDSS score of ≤ 3.5 who participated in an individualized 12 month aerobic endurance exercise program.

Peak oxygen consumption (VO₂ peak) increased and fatigue levels decreased significantly over time (p = 0.03, p < 0.02). Subgroup analysis of patients with fatigue (FSS > 4) revealed that the increase of VO₂ peak remained significant after 12 months whereas patients without fatigue did not improve any further after six months. A significant decrease of the FSS score was only observed after nine months (p < 0.03) In conclusion, aerobic exercise leads to a sustainable improvement of VO₂ peak over an extended exercise period of 12 months. There is a weak, but significant effect on fatigue levels which becomes detectable only after nine months. Since subgroup analysis revealed that MS patients behaved differently according to their baseline fatigue levels, adjustment to the individual fatigue levels is recommended for future exercise interventions in RRMS patients.

Introduction

Physical activity has emerged as an important symptomatic treatment option for patients with Multiple Sclerosis (MS) and has finally superseded the traditional concept that physical exercise might trigger relapses and worsen the natural course of disease [1], [2]. In recent years, evidence has accumulated that physical exercise may improve fatigue and peak oxygen consumption (VO₂ peak), various aspects of quality of life (QoL), depression and walking distance [3], [4], [5], [6], [7]. Based on these findings detailed recommendations for physical exercise in MS patients have been published [8] and recently been up-dated [9]. However, a direct comparison of the observed effects remains difficult since different types of interventions (e.g. endurance versus resistance training) were applied and MS patients with various degrees of disability and at different stages of the disease were included in the studies [3], [4], [5], [10], [11], [12], [13], [14], [15]. Furthermore, in most studies exercise protocols were only applied for a maximum of three months [3], [4], [5], [6], [7], [8]. Therefore, it remains to be demonstrated if the reported beneficial effects are sustainable. Last but not least, it is not known if the impact of baseline fatigue may affect exercise effects in MS patients [3], [4], [5], [6], [7], [8], [11], [12], [13], [14], [15], [16].

The present study was performed to assess the long-term effects of an individualized aerobic endurance exercise in a cohort of ambulatory patients with relapsing–remitting MS and an EDSS ≤ 3.5 over a period of twelve months using a “pre–post” design. The primary endpoints were the change in VO₂ peak and fatigue levels according to the Fatigue Severity Scale (FSS) [17]. As a secondary endpoint, changes in VO₂ peak and fatigue were analyzed according to baseline fatigue.