Effects of exercise dose and type on sleep quality in breast cancer patients receiving chemotherapy: A multicenter randomized trial

To examine the effects of different doses and types of exercise on sleep quality in breast cancer patients receiving chemotherapy. A multicenter trial in Canada randomized 301 breast cancer patients between 2008 and 2011 to thrice weekly, supervised exercise during chemotherapy consisting of either a standard dose of 25-30 min of aerobic exercise (STAN; n = 96), a higher dose of 50-60 min of aerobic exercise (HIGH; n = 101), or a combined dose of 50-60 min of aerobic and resistance exercise (COMB; n = 104). The secondary sleep outcomes in the trial were assessed by the Pittsburgh Sleep Quality Index (PSQI) at baseline, twice during chemotherapy, and postchemotherapy. We analyzed the global PSQI and the component scores. Repeated measures analyses of variance indicated that the HIGH group was statistically superior to the STAN group for global sleep quality (mean group difference = -0.90; 95 % CI -0.05 to -1.76; p = 0.039) as well as subjective sleep quality (p = 0.028) and sleep latency (p = 0.049). The COMB group was borderline statistically superior to the STAN group for global sleep quality (mean group difference = -0.76; 95 % CI +0.11 to -1.62; p = 0.085) as well as sleep duration (p = 0.051); and statistically superior for sleep efficiency (p = 0.040), and percentage of poor sleepers (p = 0.045). Compared to a standard volume of aerobic exercise, higher volumes of both aerobic and combined exercise improved some aspects of sleep quality during breast cancer chemotherapy. Exercise may be an attractive option to manage sleep dysfunction in cancer patients during chemotherapy.