Feasibility of high-intensity interval training with hyperoxia vs. intermittent hyperoxia and hypoxia in cancer patients undergoing chemotherapy – Study protocol of a randomized controlled trial

Exercise has been well demonstrated to potentially reduce chemotherapy-induced side effects and possibly aid slowing down tumor growth in cancer patients but exercise training adherence is typically low. Thus, training regimens which are perceived less strenuous but do not compromise the training-induced beneficial adaptations will help to increase adherence to exercise and reduce attrition. This 4-armed study aims to investigate the effects of high intensity interval training (HIIT) in hyperoxia versus intermittent hyperoxia and hypoxia in cancer patients undergoing chemotherapy. Forty-eight cancer patients will be randomized into either of three intervention groups or a no-training control group. Patients in the intervention groups will perform twice weekly HIIT on a cycle ergometer in hyperoxia, intermittent hyperoxia and hypoxia or normoxia. Study outcomes will be assessed before and after 4 weeks of training, while selected measures will also be performed pre- and post the first and last training session. The primary aim of this study is to investigate the feasibility, compliance, tolerance and safety of the training. Secondary endpoints will include measures of quality of life, aerobic capacity, transcutaneous oxygen saturation, red blood cell deformability, as well as the assessment of anabolic and catabolic hormone concentrations, reactive oxygen species, cytokine profiles and NK-cell cytotoxicity. To the best of our knowledge, this is the first study investigating the combined effects of exercise with modified fraction of inspired O2 in cancer patients. As such, we provide a novel approach for exercise as an adjuvant therapy in cancer patients undergoing chemotherapy.