Exercise for multiple sclerosis: a single-blind randomized trial comparing three exercise intensities.

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).