High-intensity interval training (HIIT) has just been touted as the biggest trend in health and fitness in 2018 and it looks as though it’s here to stay. I’ve been asked a lot whether or not I like HIIT training, and my answer is always yes. But as a physiotherapist, I need high-quality research to support this stamp of approval.

So I’ve put together my top six facts, all supported by high-quality research (with references), explaining why I think high-intensity interval training is so much more than just a fad, but rather a pillar on which a lot of programs should be built.

1.Stronger muscles

A Canadian study found that HIIT training involving a variety of resistance, body-weight, sprinting, kettlebells swings, battle ropes and the like for a mere six weeks was enough to improve strength by 39%, and strength-endurance by 280%.

2.Weight loss in overweight people

A review of a whole lot of studies last year showed that moderate and high-intensity interval exercise training-induced body composition improvements (reduced body fat percentage and total body fat) in overweight and obese people. Whilst similar findings were observed in the moderate intensity continuous exercise groups, the authors noted that the training volume and time commitment was significantly less with the HIIT groups.

3.Reduced risk of disease

HIIT has been proven to be effective at improving metabolic health, particularly in those at risk of or with type 2 diabetes. As a side note, the number of people with diabetes in Australia is growing by the year – so if you are at risk, chat to your doctor or health professional. Another study found that HIIT training significantly reduced the risk of heart disease in sedentary overweight young men. Know anyone that fits this description?

4.Better at improving aerobic capacity than the aerobic exercise itself.

Now, this might be hard to believe, but a huge review of 28 different studies has shown conclusively that high-intensity interval training is actually superior to continuous aerobic exercise for improving maximal oxygen uptake (VO2 max). This is probably because, after a high-intensity workout, our aerobic system has to go into overdrive to help the body recover and adapt to be a bit more adept for next time. These adaptations are still taking place in your body as long as 72 hours post workout!

5.Time efficient

When compared to conventional aerobic training, HIIT can improve skeletal muscle markers and the cardiovascular system efficiency by similar amounts with only one-tenth of the volume training.

6.More fun

A study in 2011 showed that HIIT training is perceived to be more enjoyable than moderate-intensity continuous exercise.

This article is not a sales piece for any gym, but rather what I hope is an informative and interesting synopsis of the current evidence. For the sake of presenting a balanced view, it has to be said that other forms of exercise are still excellent. Whilst the majority of evidence presented here compares HIIT training to continuous aerobic training, this is not to say that going for a long run won’t do you a lot of good.

Additionally, people engaging in HIIT training are about 15% more likely to have an injury that causes them to modify their training, than those that do regular continuous exercise. Either way, just about all exercise does more harm than good.

Wishing everyone success in their individual exercise endeavours!


Bartlett, J. D., Close, G. L., MacLaren, D. P., Gregson, W., Drust, B., & Morton, J. P. (2011). High-intensity interval running is perceived to be more enjoyable than moderate-intensity continuous exercise: implications for exercise adherence. Journal of sports sciences, 29(6), 547-553.

Buckley, S. (et al) (2015). Multimodal high-intensity interval training increases muscle function and metabolic performance in females. Applied Physiology, Nutrition, and Metabolism, 40 (11), 1157-1162.

Fisher, G., Brown, A. W., Brown, M. M. B., Alcorn, A., Noles, C., Winwood, L., … & Allison, D. B. (2015). High-intensity interval-vs moderate intensity-training for improving cardiometabolic health in overweight or obese males: a randomized controlled trial. PloS one, 10 (10), e0138853

Gibala, M. J., Little, J. P., MacDonald, M. J., & Hawley, J. A. (2012). Physiological adaptations to low ‐ volume, high‐intensity interval training in health and disease. The Journal of Physiology, 590 (5), 1077-1084

Jelleyman, C., Yates, T., O’Donovan, G., Gray, L. J., King, J. A., Khunti, K., & Davies, M. J. (2015). The effects of high‐intensity interval training on glucose regulation and insulin resistance: a meta‐analysis. Obesity Reviews, 16 (11), 942-961.

Milanović, Z., Sporiš, G., & Weston, M. (2015). Effectiveness of high-intensity interval training (HIT) and continuous endurance training for VO 2max improvements: a systematic review and meta-analysis of controlled trials. Sports medicine, 45 (10), 1469-1481.

Warburton, D. E., McKenzie, D. C., Haykowsky, M. J., Taylor, A., Shoemaker, P., Ignaszewski, A. P., & Chan, S. Y. (2005). Effectiveness of high-intensity interval training for the rehabilitation of patients with coronary artery disease. American Journal of Cardiology, 95 (9), 1080-1084.

Wewege, M., Berg, R., Ward, R. E., & Keech, A. (2017). The effects of high‐intensity interval training vs. moderate‐intensity continuous training on body composition in overweight and obese adults: a systematic review and meta-analysis. Obesity Reviews, 18 (6), 635-646.

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