A basic definition of interval training is a method of exercise in which the individual exercises in multiple bouts of higher intensive activity for a brief period of time before rest. However, I feel that because of influencers and social media “coaches” the term has been bastardized into nothing more than a mere “run for 20 seconds and rest”.
But! There is a lot of truth to what those types of people say interval training can do for you and your health, and maybe even some you did not know.
In the research collected, interval training in the format of sprinting in intervals “all-out” for 30 seconds showed to improve aerobic capacity equal or greater than if you just did moderate endurance training (Gist et al., 2013). Meaning, if you don’t want to spend a longer time than you have to mildly jog or riding a bike, mix in some interval training! You can actually get similar results in less time!
If you want to know specifically what qualifies as “high intensity”, Maillard et al. (2018) mentions that intensive intervals at 90% maximal heart rate are highly effective. Don’t know what your maximal heart rate is? No biggie, just do some simple math.
220-your age=maximal heart rate
What are the results of training like this? Well, according to the article, one would see a decrease in body fat, both visceral and total fat. Unlike other exercise methods, this particular method of exercise saw consistent results in both males and females. Now, they do recommend running as the primary way to workout, but as long as your heart rate reaches that 90% window, it really shouldn’t matter too much. Add some variety! Don’t just do one thing because an article says so!
A good rest time between reps would be between 1:30 min and 2:00 min. But when you’re working, WORK. Ideally, you should not be able to talk while doing your intense bout.
Above all this information, remember to workout smart. Do not do this type of training for longer than 30 minutes straight (if you even can). It’s best to play it safe away from injury and do smaller 5-15 minute windows of HIIT to keep yourself primed and ready to go!
I hope this information was helpful in helping you realize some things about the most overused term in fitness.
Gist, N.H., Fedewa, M.V., Dishman, R.K. et al. Sprint Interval Training Effects on Aerobic Capacity: A Systematic Review and Meta-Analysis. Sports Med 44, 269–279 (2014).
Maillard, F., Pereira, B. & Boisseau, N. Effect of High-Intensity Interval Training on Total, Abdominal and Visceral Fat Mass: A Meta-Analysis. Sports Med 48, 269–288 (2018).