Background: The most effective exercise dose has yet to be established for multiple sclerosis (MS).
Objective: The aim of this study was to investigate the effect of different exercise intensities in people with MS.
Methods: We completed a randomized comparator study of three cycling exercise intensities, with blinded assessment, was carried out in Oxford. Sixty-one adults with MS who fulfilled inclusion criteria were randomized at entry into the study, using a computer-generated list held by an exercise professional, into either: continuous (at 45% peak power, n=20), intermittent (30 sec on, 30 sec off at 90% peak power, n=21) or combined (10 min intermittent at 90% peak power then 10 min continuous at 45% peak power, n=20) exercise for 20 min twice a week for 12 weeks in a leisure facility. Groups were assessed at: baseline, halfway (6 weeks), end intervention (12 weeks) and follow-up (24 weeks). Primary outcome measure was 2 min walk.
Results: Fifty-five participants were included in the analysis (n=continuous 20, intermittent 18, combined 17). No differences were found between groups. After 6 weeks, considering all participants, 2 min walk distance increased by 6.96±2.56 m (95% CI: 1.81 to 12.10, effect size (es): 0.25, p<0.01). The continuous group increased by 4.71±4.24 m (95% CI: -3.80 to 13.22, es: 0.06), intermittent by 12.94±4.71 m (95% CI: 3.97 to 21.92, es: 0.28) and combined by 3.22±4.60 m (95% CI: -6.01 to 12.46, es: 0.04). Two minute walk did not significantly change between further assessments. Between 6 and 12 weeks there was a drop in attendance that seemed to be associated with the intermittent and combined groups; these groups also had a greater number of adverse events (leg pain during cycling most common) and dropouts (n=continuous 1, intermittent 5, combined 10). Considering all participants, 6 weeks of cycling exercise produced benefits in mobility that were maintained with further sessions.
Conclusion: While no differences were found between groups, greater benefit may be associated with higher-intensity exercise, but this may be less well tolerated. CONSORT-trial registration number (ISRCTN89009719).