Cardiorespiratory fitness (CRF) is a powerful predictor of mortality in general population and in cancer survivors. There is emerging evidence that treatments for cancer negatively impact CRF. VO2max is impaired in cancer survivors compared with healthy controls. Maximal oxygen uptakes of 15 ml/kg/min are required for functional independence and lower figures were associated with an increase in perioperative complications. Cardiopulmonary exercise tests cannot be routinely done in the clinical setting. There are some validated submaximal tests such as the one- mile and six- minutes test.