All the latest rage at my home club is HIIT or High Intensity Interval Training. Why is it all the rage? Because it has been reported to be the golden ticket to fat loss! The story goes that research has indicated that not only does high-intensity training burn fat more effectively than does low intensity exercise but it also boosts up you metabolism and keeps it revved up for some time after your workout. Well let’s examine that statement and determine if HIIT can earn a spot in your training schedule.
First, as I indicated before, I am married to a researcher so when someone says “research indicates”, I want to see said research. Unfortunately, I could not find any to back up this statement. Yes, high intensity workouts burn more calories than low intensity workouts because you use more energy. But you can exercise longer at lower intensities and could, in effect, match the calorie burn by just going longer.
HIIT proponents also point to the short recovery periods you get as the key to burning more fat. What in fact happens is that you are able to maintain a high output of energy for a longer period of time than if you did the workout straight through. More calories were burned due to the increase in exercise time, not the varied efforts.
But what about the fact that you will burn more calories/fat due to higher post-exercise metabolism? One study researched this effect and they called it Excess Post-Exercise Oxygen Consumption (EPOC). In a 2006 article in the Journal of Sport Sciences researchers found that more intense exercise creates a higher EPOC than low intensity workouts but that this number was only 6- 15% of the net oxygen cost. That means if you pushed really hard for an hour or so and burned a 1000 calories, post-exercise burn could add another 60 to 150 more calories, about the same as if you went at a lower intensity for another 10 min or so. More importantly the better shape you are in the less post burn you get, because you recover faster.
So, if it doesn’t burn fat, what good is it? High Intensity Interval Training makes you faster! Used wisely and not over done it is a great tool to have in your training schedule. The problem comes when athletes over use it thinking the benefits are greater than they truly are and wind up injured and exhausted.
Want to trim fat before next season? Eat better and pile on the low intensity/longer workouts. You will get more calorie burn at a lower risk as well as at a pace you can maintain for a month or two. Save the HIIT for the fine tuning and speed gain later in your training calendar.
By Coach Bob Seaman