What is the minimal dose of HIIT required to achieve pre‐operative benefit

Abstract

We read with interest the article by Boereboom et al 1 in the Scandinavian Journal of Medicine Science in Sport. This well-performed study showed that a short (8 sessions over 19 days) pre-operative exercise training program increased exercise time and workload in the second cardiopulmonary exercise test (CPET), but did not lead to a change in participants' peak VO 2. We agree with the statement in the discussion that "Further work should be undertaken to explore exercise modality, training intensity, interval length and session frequency to try and determine an optimal HIIT protocol to improve the cardiorespiratory fitness (CRF) of preoperative patients in the short time-frame available." However, we feel that the title of the paper and the main conclusion that "short-term preoperative high-intensity interval training does not improve fitness of colorectal cancer patients" is potentially misleading.The main reason for our concern is related to the volume of intense exercise administered. This paper shows that a median intense exercise volume of 40 minutes (40 × 1 minute high-intensity exercise) does not improve peak VO 2 . This, therefore, makes an important contribution to the literature. Dunne et al showed an improvement of 2 mL/kg/min in peak VO 2 with 12 HIIT exercise sessions 2 before liver surgery. Each session was 40 minutes long, with 30 minutes spent alternating between low-and high-intensity exercise. It is not clear how many minutes of intense exercise were performed, but it was probably close to 120 minutes. We have recently completed a randomized trial 3,4 with a number of clinical similarities to this study. We demonstrated an improvement in peak VO 2 of 2.87 mL/kg/min. Our participants attended on average 12 sessions and on analysis performed 8 minutes of intense exercise per session, giving an approximate total of 100 minutes of intense exercise. This was associated with favorable trends in clinical outcomes.Future research should examine the number of sessions and the number of intense intervals needed to improve peak VO 2 over a period of 3-4 weeks. For example, while 40 minutes of high-intensity exercise is not enough to increase peak VO 2 , and 100 minutes of high-intensity is, we do not know what the impact of 80 minutes of high-intensity exercise (a volume that could be achieved in 8 sessions) will be. We have commenced a study to help define the dose-response curve between number of sessions of HIIT and change in peak VO 2 , in both average and high risk patients. Filling this gap in our current knowledge will help determine how best to prescribe HIIT in the context of variable surgical waiting times. We therefore believe that it is premature to conclude that "shortterm preoperative high-intensity interval training does not improve fitness of colorectal cancer patients." ORCID Kari Cliffordhttps://orcid.org/0000-0002-4908-7413 REFERENCES 1. Boereboom CL, Blackwell J, Williams JP, Phillips BE, Lund JN. Short-term pre-operative high-intensity interval training does not improve fitness of col...

Moderate-intensity exercise training or high-intensity interval training to improve aerobic fitness during exercise prehabilitation in patients planned for elective abdominal cancer surgery?

“…Participants only attended a median of eight out of twelve intended exercise sessions. This low amount of attended HIIT sessions (40 min of HIIT with an estimated energy expenditure of 343 Kcal) might not have been a sufficient training volume to improve VO 2 at the VAT or VO 2peak [42]. This is further emphasized by the fact that essentially the same HIIT exercise prescription, though with higher exercise session attendance rates (and therefore higher training volumes), did manage to increase VO 2 at the VAT and VO 2peak in healthy adults (60 min of HIIT, with an estimated energy expenditure of 491 Kcal) [43] and in patients with urological cancer (55 min of HIIT with an estimated energy expenditure between 417 and 479 Kcal) [17].…”

Association of Preoperative High-Intensity Interval Training With Cardiorespiratory Fitness and Postoperative Outcomes Among Adults Undergoing Major Surgery

“…High-intensity interval training involves repeated aerobic high-intensity intervals at approximately 80% of the maximum heart rate, followed by active recovery. The rapid increases in CRF elicited with HIIT is appealing for preoperative patients, and in the context of pathology, age, and comorbidities, the volume of training stimulus required to improve CRF can often be achieved …”

“…The rapid increases in CRF elicited with HIIT is appealing for preoperative patients, and in the context of pathology, age, and comorbidities, the volume of training stimulus required to improve CRF can often be achieved. 22 …”