High-Intensity Interval Training (HIIT): An effective strategy for maximizing health and fitness
Efthymios Papadopoulos(1,2), R.Kin, MSc & Jenna Gillen(1), PhD
- (1)Faculty of Kinesiology and Physical Education, University of Toronto
- (2)Cancer Rehabilitation and Survivorship, Princess Margaret Cancer Centre
The Canadian Physical Activity Guidelines recommend accumulating 150 minutes of moderate-to vigorous-intensity physical activity per week to maintain or improve health(1). For many Canadians, this is typically achieved through routine bouts of moderate-intensity continuous training (MICT), such as 30 minutes per day on 5 days per week. However, a large and convincing body of research indicates that achieving only 40 to 60 minutes of high-intensity interval training (HIIT) per week leads to similar, and sometimes greater, health benefits(2-5). HIIT involves short bouts of high-intensity exercise (>85% HRmax) interspersed with recovery periods of low-intensity exercise or rest(6). The utility of HIIT has been well described in healthy individuals(2) and there is growing evidence demonstrating its safety and applicability to clinical populations(3-6).
Most HIIT studies have employed cycling, but other modes of traditional whole-body exercise can also be effective, such as interval walking, stair climbing, and running. One study also found that subjects who trained using 1 set of 8 × 20secs of a single exercise (burpees, jumping jacks, mountain climbers, or squat thrusts) interspersed by 10secs of rest per session, 4 times per week for 4 weeks increased maximal oxygen consumption (VO2max) to the same extent as a group who performed 30 min of MICT per session(7).
Common HIIT Protocols
Several HIIT protocols with different interval-recovery ratios and duration can be found in the literature. The following three protocols have been widely used in both healthy and clinical populations:
- 4 x 4min at ~90% HRmax interspersed by 3min recovery. Total duration: ~28min(3)
- 10 x 60secs at ~90% HRmax interspersed by 60secs recovery. Total duration: ~20min(6)
- 4 x 30secs of maximal effort followed by 4min recovery. Total duration: ~20min(8)
Evidence suggests that HIIT can be safely performed in healthy populations as well as those with chronic diseases, such as cardiovascular disease, type 2 diabetes, and several types of cancer. As with the initiation of any new exercise program, it is important to undergo appropriate screening by a qualified exercise professional and/or a medical professional.
HIIT vs. MICT for Improving Health and Fitness
The most well documented advantage of HIIT compared to MICT is an improvement in VO2max demonstrated in both healthy and clinical populations(2-5). Research also shows that HIIT may be more effective than MICT in improving insulin sensitivity, endothelial and antioxidant activity and reducing inflammation. In addition to the physiological benefits, emerging research suggests that HIIT is a more motivating and has better adherence rates than MICT.
HIIT is an effective strategy for improving health and fitness in a variety of populations. Considering a large number of individuals do not meet current physical activity guidelines, qualified exercise professionals, such as Registered Kinesiologists, are encouraged to consider HIIT as an aerobic modality to maximize client/patient health outcomes.
- Tremblay MS, Warburton DER, Janssen I, Paterson DH, Latimer AE, Rhodes RE, et al. New Canadian Physical Activity Guidelines. Appl Physiol Nutr Metab 2011;36(1):36–46.
- Milanovic Z, Sporis G, Weston M. Effectiveness of High-Intensity Interval Training (HIT) and Continuous Endurance Training for VO2max Improvements: A Systematic Review and Meta-Analysis of Controlled Trials. Sports Med. 2015;45(10):1469-81.
- Devin JL, Sax AT, Hughes GI, Jenkins DG, Aitken JF, Chambers SK, et al. The influence of high-intensity compared with moderate-intensity exercise training on cardiorespiratory fitness and body composition in colorectal cancer survivors: a randomised controlled trial. J Cancer Surviv 2016;10(3):467-479.
- Jung, M. E., Bourne, J. E., Beauchamp, M. R., Robinson, E., & Little, J. P. High intensity interval training as an efficacious alternative to moderate-intensity continuous training for adults with prediabetes. Journal of Diabetes Research, vol. 2015, Article ID:191595, 9 pages, 2015.
- Tjonna, A. E., Lee, S. J., Rognmo, O., Stolen, T. O., Bye, A., Haram, P. M., Wisloff, U. Aerobic interval training versus continuous moderate exercise as a treatment for the metabolic syndrome: A pilot study. Circulation, 2008;118(4), 346-354.
- Gillen JB, Little JP, Punthakee Z, Tarnopolsky MA, Riddell MC, Gibala MJ. Acute high-intensity interval exercise reduces the postprandial glucose response and prevalence of hyperglycaemia in patients with type 2 diabetes. Diabetes Obes Metab 2012;14(6):575–7.
- McRae G, Payne A, Zelt JGE, Scribbans TD, Jung ME, Little JP, et al. Extremely low volume, whole-body aerobic–resistance training improves aerobic fitness and muscular endurance in females. Appl Physiol Nutr Metab. 2012;37(6):1124–31.
- Gibala MJ, Little JP, van Essen M, Wilkin GP, Burgomaster K a, Safdar A, et al. Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance. J Physiol. 2006;575:901–11.