Breast, colorectal and prostate cancer have among some of the highest cancer survival rates in Australia, yet treatments for these cancers have been associated with increased fat mass, reduced skeletal muscle mass and increased systemic inflammation. Collectively, these treatment-related changes not only reduce quality of life but also increases the risk of both disease recurrence and comorbidities. Exercise following cancer diagnosis and treatment can reduce the risk of disease recurrence. However, the physiological mechanisms that explain this relationship are not clear. One potential mechanism relates to the acute release of myokines in response to exercise. The aim of this randomised control trial is to compare changes in the acute response of myokines (IL-15, IL-10, TNF-α and IL-6) to a single bout of high intensity interval training (HIIT) (4x4min) session and changes in cardiorespiratory fitness and body composition in breast, prostate and colorectal cancer survivors following before and after six months of HIIT. At baseline, participants (n=50 for each group) will complete a V̇O2peak test and have their body composition assessed (using dual-energy X-ray absorptiometry). Before and after a single HIIT session, venous blood will be sampled for the analysis of IL-6, IL-10, IL-15 and TNF-α. Participants will then complete three HIIT sessions per week for six months before all testing is repeated. It is hypothesised that the acute changes in the myokine response to a single HIIT session will be greater following training but that there will be no change in baseline (resting) levels. Training-induced changes in the myokine response to HIIT will be related to changes in body composition and cardiovascular fitness that occur over the six months.