Trends come and go in the fitness world, but one that looks like it might stick around is High Intensity Interval Training (HIIT). While it’s not a new concept, it’s definitely gaining popularity. This is especially apparent in the online world with many fitness programs promising to transform your body in a few short weeks with the magic of HIIT.
So what exactly is HIIT and why are so many people doing it?
Shelley Keating is an exercise physiologist and researcher from the University of Queensland. She says High Intensity Interval Training (HIIT) involves repeated bursts of high intensity (i.e. hard) exercise, interspersed with low intensity recovery periods.
“Lack of time is commonly reported as a barrier to participating in regular exercise. HIIT allows you to perform a shorter session of exercise and gain the same or – for some health parameters such as fitness – a superior benefit,” she says.
Thousands of HIIT devotees cite the benefit of shorter workouts with maximum results (and there are copious amounts of six-pack selfies on Instagram to prove it!). And experts agree there are benefits of incorporating HIIT into your routine, so what’s not to love?
Dr Richard Metcalfe, a Lecturer in Exercise and Health at the University of Ulster, Northern Ireland, believes it’s important to research HIIT. He agrees with Shelley that one of the most common barriers to exercise is lack of time.
“If we can show that you can achieve similar health benefits, but with a lower volume of exercise and lower time-commitment, then I think it’s worth studying,” he says.
Richard’s research has compared very low volumes of ‘all-out’ cycling exercise (~2-4 x 20-30 second ‘all-out’ efforts; 1-2 minutes of ‘all-out’ exercise/session) to very high volumes of traditional aerobic exercise (45-60 minutes of moderate cycling).
“What these studies show is that you get very similar aerobic adaptations, and improvements in glucose metabolism, with both of these exercise regimes. In other words, all-out HIIT provides more for your efforts, both in terms of the time commitment and the volume of exercise required,” he says.
Is High Intensity Interval Training for you?
Like everything, there’s no one size fits all approach to exercise, including HIIT. Richard says HIIT is relative to every individual’s level of fitness and the high-intensity aspect shouldn’t put people off.
“High-intensity for one person might involve fast running, whilst for some it might involve brisk walking. Even HIIT protocols that ask for an ‘all-out’ effort; that effort is still relative to that individual’s fitness and ability,” he says.
Australian physical activity guidelines for adults (between ages 18 and 64) advise an accumulation of 150 to 300 minutes (2 ½ to 5 hours) of moderate intensity physical activity or 75 to 150 minutes (1 ¼ to 2 ½ hours) of vigorous intensity physical activity, or an equivalent combination of both, each week. Two resistance sessions should also be included in your week.
“These targets are set as known levels to maintain or improve health. To achieve this you may wish to walk, run, cycle, swim, bush-walk, play tennis etc, or go to the gym and you may choose to include HIIT. The best type of exercise is the one you enjoy and will commit to in the long term,” Shelley says.
If you like exercising at higher intensities and don’t mind increasing your usual effort and exertion, then HIIT could be something you’ll like.
But don’t be fooled by the time-efficiency argument. As Richard explains: “HIIT intersperses periods of high-intensity effort, with periods of low-intensity effort. When you add both of these components together, this means that many HIIT protocols are not as time-efficient as is sometimes claimed. This is what my research, looking at very short ‘all-out’ efforts, is attempting to solve.”
Personal trainer and EnVie Woonona gym owner Alita Ashcroft says you should have a base level of fitness and a good understanding of how to complete HIIT exercises correctly if you want to incorporate it into your routine.
“It’s important that you’re body aware and that you know your own limitations. There’s a higher level of injury risk with HIIT if you’re doing it in an unsupervised environment, so do your research and be careful,” she says.
If you’d like to try HIIT then make sure you seek approval from a doctor if you’re new to this type of exercise, have health concerns or you’re over the age of 50.
To find out more about Australia’s Physical Activity and Sedentary Behaviour Guidelines click here.
Kate Mayhew is a journalist and fitness enthusiast, currently embarking on a new career in the fitness industry. She is studying Certificate III in Fitness through the Personal Training Academy.