HIIT It with the Right Intensity

With all the buzz around HIIT, or High Intensity Interval Training, I wanted to shed some light on this style of exercise. From big-box gyms to streaming services, you’re sure to see a HIIT type of training offered. And no wonder!

HIIT has been shown in various studies to be more efficient at caloric burn in the fat-torching department than steady-state cardio, both during and after your workout. Everyone wants to get the most bang for their buck, so why not go to as many HIIT classes as possible?

Well, this is where we need to make sure we fully understand that not all HIIT classes are the same, specifically on the caloric burn level. This is where I’m happy to step in and shed some light on these HIIT-style workouts.

Here are a few types you should know:

1. HIIT and SIT Workouts

Now, research indicates that High Intensity Interval Training workouts are an efficient way to burn fat because these exercises are intended to use maximum effort for short periods of time. When I say maximum effort, I mean exhaustive I-cannot-push-for-one-more-second effort.

These true HIIT or SIT (Sprint Interval Training) workouts stem from athletic conditioning programming to make athletes stronger, faster, or more explosive. These bouts of exercise are short—think an Olympic lifter trying for their record weight of a Deadlift or Clean, or a sprinter pushing their maximum effort for 100-yard dash. These efforts take mere seconds, but they tax all of their energy stores that make them able to do these incredible weights or speeds. Recovery time can take up to five minutes for only six or 12 seconds of work.

This, my friends, is HIIT. I don’t know many group fitness classes that program efforts in this way; it would make for a pretty short class and unappealing for some!

VIIT: Variable Intensity Interval Training

This is what many HIIT circuits really are, or this is what they should be. In order to get the most out of the workout, the participant needs to have adequate recovery between sets of moderate to high Intensity. VIIT circuits are typically stations of different exercises that work various muscle groups at 45-60 seconds per station, which is a lot different than six-to-12 seconds of all-out effort. There may be light-to-moderate weights and/or cardio to keep the heart rate up. Each set of the circuit can finish with active recovery, like a core set or bodyweight cardio.

These classes run 30 minutes to an hour, so they don’t fit the typical mark of 20 minutes that HIIT takes. The human body simply cannot take that type of taxing effort for more than 20 minutes, and therefore VIIT is the technical term for these group-fitness models.

HVIT: High Volume Interval Training

These classes or programs focus on doing as many repetitions as possible for a certain amount of time. Think a CrossFit WOD, an EMOM (Every Minute on the Minute), an AMRAP (As Many Rounds as Possible) circuit, or rep challenges. These became popular recently because they’re flexible—you can put together a multitude of workouts using bodyweight exercises, dumbbells, barbells, suspension trainers, heck anything! They challenge any fitness level and can be done in groups or on your own.

Be careful with high volume, because all that work for prolonged periods of time can increase the risk of injury. As the body gets tired, because there is limited recovery built in to these workouts, form gets compromised. If weights are involved, this can be very problematic. So, while these workouts can be fun and short, they come with an increased risk of injury, so be careful!
I know it’s hard engaging with fitness professionals with COVID still keeping things restricted, but if you’re trying out HVIT, VIIT, or a true HIIT, make sure you’re getting plenty of rest in between. Your fitness level may not be the same as the person who designed the program. If you have any doubts about form while using weights, put the weights down and do the work without them.

Author’s note: Some information for this post came from the National Academy for Sports Medicine. 

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