Purpose Exercise therapy improves perioperative outcomes and is used for prehabilitation and in some aspects of post operative care. High intensity interval training (HIIT) is a time and space efficient form of exercise that may be suited to the hospital setting. This study aims to investigate the impact of an in-hospital postoperative HIIT regime on functional measures, quality-of-life and surgical outcomes following foregut cancer surgery. Methodology A randomised controlled trial in patients with foregut malignancy undergoing surgical resection. The HIIT intervention consisted of daily aerobic and resistance exercises. The primary outcomes were hand grip strength, and six-minute walk test (6MT). Secondary outcomes included surgical morbidity, length of stay and quality of life as measured with the European Organisation of Research and Treatment of Cancer questionnaire (EORTC-QLQ) and Hospital depression and anxiety scale (HADs). Results 66 patients were enrolled in this study (n=34 intervention, n=32 control). The HIIT-intervention group experienced significantly lesser reductions in left-handed grip strength (HIIT -0.6±0.7 vs control -1.5±1.0, p<0.001) and 6MW distance achieved (HIIT -83.5±13.9 vs control -94.0±17.6, p=0.014). The majority of EORTC-QLQ measures were improved in the intervention arm. (p<0.05). No difference between groups was found in hospital length-of-stay. Conclusions In-hospital post-operative HIIT effectively attenuated perioperative losses in functional fitness and was associated with better perceived quality-of-life. Implementation of HIIT into cancer treatment strategies may improve surgical morbidity and patient satisfaction.