HIIT: What is it?
HIIT stands for High Intensity Interval Training and contrary to what all the Insta fitspos might say, it’s not simply a label for a hard interval-based workout that leaves you sweating buckets and gasping for air.
Just like a 20/10 interval workout isn’t automatically a Tabata!
HIIT is actually defined in the fitness space.
HIIT requires alternating efforts of high and low-intensity exercise where the high-intensity work is done above the lactate threshold, near VO2max (90+%).
VO2max is the maximum capacity of an individual's body to transport through circulatory system and use oxygen in motor muscles.¹
And while there is some correlation between heart rate and VO2max, they aren’t the same thing. So just because a workout gets your HR to a higher zone, doesn’t necessarily mean you’re working at similarly high % of your VO2max.
The workouts commonly found online that are self-described as HIIT typically involve dumbbells, bodyweight exercises, plyometrics or core work. All of these things can be a great addition to your training! But none of them fall into the category of HIIT (generally speaking because these modalities lack the ability/possibility of getting you to work at 90+% VO2max).
So if jumping lunges, burpees and mountain climbers aren’t HIIT - What is?
The common modalities used to perform a HIIT workout are treadmill running, swimming, rowing, cycling, and outdoor sprinting (indoor sprinting is called SIT and it’s own classification of workout).
Typical work intervals for HIIT are between 30s and 4 mins with rest periods (which can be no work or “passive” easy work) commonly being the same amount of time as the work period (or longer).
Okay, so we know what HIIT is and isn’t… but let’s circle back.
What are those workouts that aren’t HIIT but are hard and time-based?
Typically interval-based work like the workouts mentioned above (including dumbbells, bodyweight, plyos, core, etc.) are Hight Intensity Circuit Training (HICT), High Intensity Functional Training (HIFT) or simply called “circuits”.
HIIT does has specific health benefits that are hard to come by doing other forms of workouts BUT that doesn’t means these kinds of workouts aren’t “bad”.
On the contrary: if it’s something you enjoy and it helps you move your body and reach the recommended 150 min/week of moderate intensity aerobic activity, then GREAT! Keep doing it!! While it might not have the same benefits as real HIIT, there are still benefits to be gained.
Simply put:
It’s just not HIIT - and if you’ve been around here for awhile you know I’m a believer that using correct terminology and understanding that terminology makes a difference and is beneficial for all of us.
Let’s recap, shall we?
🗣HIIT is a specific kind of workout and not everything qualifies as HIIT
🗣Things that are not HIIT are not “bad” because of it
🗣Enjoy your group fitness classes and insta workouts if it’s what gets you moving!
Have questions?
Drop them in the comments & lets chat!
¹Habibi, E., Dehghan, H., Moghiseh, M., & Hasanzadeh, A. (2014). Study of the relationship between the aerobic capacity (VO2 max) and the rating of perceived exertion based on the measurement of heart beat in the metal industries Esfahan. Journal of education and health promotion, 3, 55. https://doi.org/10.4103/2277-9531.134751