Myokine Responses To High Intensity Exercise: Relationships With Cardiorespiratory Fitness And Body Composition In Cancer Survivors

PURPOSE: Pre-clinical murine and in vitro models have demonstrated that exercise suppresses tumour and cancer cell growth, respectively. In these investigations, the anti-oncogenic effects of exercise were associated with the exercise-mediated release of myokines (i.e., interleukin (IL)-6 and IL-15). However, no study has quantified the acute myokine (IL-15) response in human cancer survivors, or whether physiological adaptations to exercise training (i.e., body composition and cardiorespiratory fitness) influence the myokine response. The aim of this study was to explore the acute myokine response to a bout of high-intensity interval exercise (HIIE) and examine the relationships with body composition and cardiorespiratory fitness before and after 7-months of high-intensity interval training (HIIT) in cancer survivors. METHODS: Breast, prostate, and colorectal cancer survivors (n = 14) completed 7-months of HIIT. Blood was sampled immediately before and after an acute bout of HIIE at baseline, which was repeated following 7-months of training. Post-HIIE myokine responses (IL-15, IL-6, IL-10, and IL-1ra) were compared to body composition (dual-energy X-ray absorptiometry) and cardiorespiratory fitness (V̇O2peak) at baseline and after 7-months of HIIT. RESULTS: An acute bout of HIIE increased (35-100%) post-exercise concentrations of IL-15, IL-6, IL-10, and IL-1ra at baseline and after training (p < 0.05). There was no significant effect of training on the post-HIIE myokine response. Higher post-HIIE concentrations of myokines were positively associated with lean mass (p < 0.05), but not cardiorespiratory fitness, before and after HIIT. Increases in lean mass in response to HIIT were positively associated with post-HIIE myokine concentrations (r = 0.618-0.867, p < 0.05). CONCLUSIONS: High intensity interval exercise can significantly increase myokine concentrations in cancer survivors. The anti-inflammatory effect of exercise was mediated, at least in part, by lean mass. Exercise interventions that target improvements in lean mass may lead to superior myokine responses, which have been associated with the anti-oncogenic effect of exercise thus improving outcomes for survivors. NHMRC partnership grant (APP1132361) and (Tour de Cure (RSP-284-FY2023)