Higher-intensity exercise helps cancer survivors remain motivated

Purpose: The aim of the present study was to determine if exercise intensity impacts upon the psychosocial responses of breast and prostate cancer survivors to a rehabilitation program.

Methods: Eighty-seven prostate and 72 breast cancer survivors participated in an 8-week exercise and supportive group psychotherapy intervention (n = 84) or control (n = 75) group. Intervention participants were randomized to low-to-moderate intensity exercise (LIG; n = 44; 60-65 % VO2peak, 50-65 % one repetition maximum (1RM)) or moderate-to-high intensity exercise (HIG; n = 40; 75-80 % VO2peak, 65-80 % 1RM) while controls continued usual care. Before and after the 8 weeks, all participants completed the Functional Assessment of Cancer Therapy-Breast or -Prostate to assess quality of life (QOL) and Behavioural Regulations of Exercise Version 2 for exercise motivation. Intervention participants also completed a follow-up assessment 4 months post-intervention.

Results: All three groups improved in QOL from baseline to post-intervention, with no significant differences. From post-intervention to follow-up, the LIG and HIG similarly maintained QOL scores. Between baseline and post-intervention, both intervention arms improved their motivation to exercise compared to the controls (p = 0.004). At the 4-month follow-up, the HIG had maintained their overall exercise motivation (p < 0.001) and both domains of intrinsic motivation (identified regulation, p = 0.047; intrinsic regulation, p = 0.007); however, the LIG had regressed.

Conclusions: The structured intervention was successful at improving autonomous exercise motivation, regardless of exercise intensity. However, only those participants who had exercised at a higher intensity sustained their improvement. Intervention participation did not improve QOL more than controls.

Implications for cancer survivors: Higher-intensity exercise is more likely to result in more sustainable increases in motivation to exercise among cancer survivors.