Greatist Op-Eds analyze what's making headlines in fitness, health, and happiness. The thoughts expressed here are the author's and don't necessarily reflect Greatist's outlook.
This week, New York Times PhysEd columnist Gretchen Reynolds posted an article on the evolution of the “minimalist” workout. Over the last few years, she wrote, research has shown people can achieve some of the same health benefits that they get from endurance training in workouts lasting as little as four minutes.
High-intensity interval training (HIIT) is a type of exercise that involves alternating periods of high and low-intensity activity, and it’s gained a global reputation as a way to get fit fast — with the science to back it up. Some media outlets have heralded the development of HIIT as a godsend for people with busy schedules, the idea being that there’s no plausible excuse for backing out of a workout that lasts just a few minutes.
But what’s still unclear is how the growth of HIIT is changing our relationship to exercise in the broader sense. Is the proliferation of ultra-efficient workouts just promoting exercise as a means to an end?
What’s the Deal?
Multiple studies have found that interval (specifically HIIT) and endurance training can produce similar muscle adaptations, and both help reduce aortic stiffness and increase insulin sensitivity. In other words, both types of exercise can help prevent heart disease, hypertension, and diabetes Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance. Gibala, M.J, Little, J.P., van Essen, M., et al. Journal of Physiology 2006 Sep 15;575(Pt 3):901-11. Sprint interval and endurance training are equally effective in increasing muscle microvascular density and eNOS content in sedentary males. Cocks, M., Shaw, C.S., Shepherd, S.O., et al. School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, U.K. Journal of Physiology 2013 Feb 1;591(Pt 3):641-56. Similar metabolic adaptations during exercise after low volume sprint interval and traditional endurance training in humans. Burgomaster, K.A., Howarth, K.R., Phillips, S.M., et al. Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada. Journal of Physiology 2008 Jan 1;586(1):151-60. A practical model of low-volume high-intensity interval training induces mitochondrial biogenesis in human skeletal muscle: potential mechanisms. Little, J.P., Safdar, A., Wilkin, G.P., et al. Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada. Journal of Physiology 2010 Mar 15;588(Pt 6):1011-22.. That seems like great news for the millions of people who have trouble finding time to work out regularly. Surveys in the U.K. suggest the number one reason why people say they don’t exercise enough is because they don’t have enough time. With a workout routine that requires just a few minutes three or four times a week, that excuse becomes less powerful.
Why It Matters
As HIIT becomes more common, parts of the fitness industry’s focus seems to have shifted from making exercise enjoyable to finding out the bare minimum we can get away with. (See headlines such as: “Five ways you can exercise less and lose more.”) And while it’s worth celebrating these insights into exercise physiology, it’s also easy to foster the impression that working out isn’t inherently exciting or pleasurable. Instead of trying to make physical activity part of an overall healthy lifestyle, emphasizing the time-saving aspect of HIIT has shifted our attention to just getting it over with.
Focusing heavily on how HIIT reduces the amount of time we need to spend at the gym can obscure the fact that we might actually like doing intervals. And recent studies have found some people really do enjoy HIIT over “traditional” endurance training (though it’s unclear exactly why) High-intensity interval running is perceived to be more enjoyable than moderate-intensity continuous exercise: implications for exercise adherence. Bartlett, J.D., Close, G.L., MacLaren, D.P., et al. Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK. Journal of Sports Sciences 2011 Mar;29(6):547-53. Adding sprints to continuous exercise at the intensity that maximizes fat oxidation: implications for acute energy balance and enjoyment. Crisp, N.A., Fournier, P.A., Licari, M.K., et al. School of Sport Science, Exercise and Health, The University of Western Australia, Crawley, Australia. Metabolism 2012 Sep;61(9):1280-8.. And when it comes to sticking with an exercise routine, that enjoyment is a key factor in predicting whether people will actually stay on track Assessment of factors associated with exercise enjoyment. Wininger, S.R., Pargman, D. Western Kentucky University, USA. Journal of Music Therapy 2003 Spring;40(1):57-73. Importance of enjoyment when promoting physical exercise. Hagberg, L.A., Lindahl, B., Nyberg, L., et al. Scandinavian Journal of Medicine and Science in Sports 2009 Oct;19(5):740-7.. People might see interval training the same way they see any other kind of exercise, looking forward to the physical exertion instead of dreading the obligation.
Of course, many fitness experts stress the importance of finding an exercise routine that works for the individual — one that we like, that keeps us physically and mentally healthy, and that we’ll stick with for the long haul. For some people, that might mean HIIT; for others, that could mean running ultra-marathons. Intervals are efficient, sure, but their time-saving properties aren’t always the cure-all excuse-killer we often read about in headlines.
If interval training can help people by making exercise more accessible, it’s A-okay in our book. But it’s also important to remember exercise doesn’t have to be a means to an end. In fact, what makes many people stick to a fitness regimen is the (sometimes long and arduous) process of challenging our minds and bodies as we pound the metaphorical pavement — not just the prospect of fitting into those skinny jeans.
That’s why, when touting the benefits of intervals, trainers and the media should be careful not to put too much focus on the “get-it-done-quickly” aspect of HIIT. The key is that people enjoy their exercise routine; for many people, intervals aren't just fast, they lead to the kind of fulfillment that keeps us lacing up our sneakers for a lifetime.
Have you tried interval training? How has it changed your relationship to exercise? Let us know in the comments below or tweet the author at @ShanaDLebowitz.