“HIITing” the Mark: The developing an optimal high-intensity interval training (HIIT) protocol for improving fitness before abdominal surgery

A full pre-operative anaesthetic assessment will be performed for each participant, and this is part of the standard treatment that they receive if they are patients scheduled for abdominal surgery. Participants will be categorised as either fit or unfit, by means of the Duke Activity Survey, initial cardiopulmonary exercise testing (CPET), and a modified frailty index. CPET will be performed on an electromagnetically braked ergometer using individualised stepped protocols based on the individual’s fitness levels. This will be supervised by a senior researcher with medical staff also on site. Peak VO2, anaerobic threshold, respiratory exchange ratio and the workloads required to elicit 60% and 90% maximal heart rate will be documented. CPET will be repeated throughout the exercise program to test for changes in Peak VO2. The exercise program will include 24 sessions, 3-4 times a week, over approximately eight weeks. This will include five sessions of CPET (sessions 1,6,10,14 and 24) and 19 of HIIT. The HIIT sessions, which will be supervised by a trained exercise physiologist, will be performed on Monarch cycle ergometers, with monitoring of pulse and blood pressure. The HIIT sessions will aim to achieve ten 1-minute intervals of high-intensity cycling (against resistance) followed by ten 1-minute intervals of active rest (gentle cycling against no resistance) and will then progress to five 2-minute intervals of high-intensity work followed by 2-minutes of active rest. Intense exercise may be for shorter periods of time in unfit participants. The sessions will be individualized, with differences in the duration of intense exercise on starting HIIT, progression of exercise intensity over time, and adherence to exercise targets (such as reaching a heart rate of 90% of an age defined maximal heart rate) being noted. Whilst the session is individualised, we may have groups of up to 4 patients undertaking a HIIT session at a time, and this will take place at Dunedin Hospital in an exercise room. If the participant’s surgery is delayed, he or she will be invited to complete one additional HIIT session per week up until surgery. Each session will last approximately 30 minutes. After surgery, patients will complete a postoperative morbidity survey and quality of life questionnaire.