Why Your High-Intensity Interval Training (HIIT) Isn’t Making Any Promises
High-intensity interval training (HIIT) gained attention in the 2010s with one specific claim: short bursts of intense exercise can provide the same aerobic benefits as longer runs or cycling. But the HIIT videos you can watch today bear little resemblance to the original model, and many aren’t worth your time.
Before we get into the differences, I want to make one thing clear: if you enjoy making videos labeled “HIIT” and they’re part of a workout routine that you genuinely enjoy, keep doing them . I’m not trying to take away what you love.
But if you’re doing it because you think it’s the best way to reach your goals, or because a trainer or blogger tells you it’ll burn a ton of calories or give you a big butt, we need to talk a little bit.
What is “real” high-intensity interval training (HIIT)?
High-intensity interval training (HIT) emerged as a buzzword after exercise scientists noticed that people were improving their performance on the Wingate test with each repetition. The Wingate protocol requires participants to pedal a stationary bike at full throttle, with high resistance, for 30 seconds, raising the bar to the point of vomiting. Then, they rest for four minutes, and then repeat.
After further experiments, the researchers found that the benefits they observed, including increased aerobic endurance, could be due to other work-rest combinations. The Tabata protocol, also performed on a research-grade stationary bike (called a “cycle ergometer”), involves 20 seconds of work and 10 seconds of rest, repeated “seven to eight times” until exhaustion was reached in the original study—or about four minutes in total.
These aren’t the kind of workouts people do for fun. Everyone who’s reported experiencing them said it was pure agony . Scientists often note that people rarely push themselves hard enough to replicate these exercises on their own. Workouts and videos don’t offer such intense workouts either. Peloton offers Tabata classes, which require you to complete these four-minute blocks multiple times in a single workout, meaning you definitely won’t exhaust yourself the first time.
To create a more accessible version of HIIT, Martin Gibala, one of the researchers who popularized the concept, worked to find a protocol that ordinary people could perform independently and that wouldn’t leave them so tired that they’d be afraid to return to exercise. He concluded that an interval of one minute of work and one minute of rest is optimal , and it can be performed while cycling, jogging, or other aerobic exercise. Interval training, using varying work and rest intervals, has gained immense popularity.
Another affordable HIIT option is the Norwegian 4×4 , which uses four-minute intervals of intense, but not exhausting, work with three minutes of rest between, repeated four times. It takes longer than the HIIT protocols mentioned above—about 40 minutes for a full workout—but has been proven effective for improving cardiovascular fitness.
How do new high-intensity interval training (HIIT) videos compare to new ones?
The term HIIT hasn’t just blurred; it’s mutated. Originally, HIIT meant getting more results in less time, so it gained a reputation for being more effective, perhaps even superior to workouts like jogging. And because HIIT doesn’t require a bike, trainers seized on the idea and began applying the term to literally anything they could think of. Bodyweight squats? Dumbbell curls? Sure, why not. As a result, today, HIIT means more than just “a workout video with a timer in the corner.”
HIIT’s popularity had been growing for years until the COVID pandemic hit, when it exploded. If you’re a trainer or influencer trying to come up with something easily filmable, you’ll probably prefer equipment-free, at-home workouts. And to make them sound more appealing, you’ll call them HIIT.
I suspect the “HIIT” label for bodyweight training is supposed to mean “good enough.” Yes, you’re doing a few lunges in your living room, but the trainer wants you to think it’s just as good as doing it in a small studio or a full-fledged gym. Maybe even better. For whatever reason you’re training for—burning calories.
The promises of HIIT-style workouts cannot be trusted.
The promises these workouts make suggest how far they are from true high-intensity interval training (HIIT). Do they claim to improve your VO2 max , which was originally one of the benefits they claimed? Usually not. Let’s quickly clarify:
Do they burn a lot of calories? Not necessarily, but it depends on the workout. The longer the workout and the more out of breath you are, the more calories you burn. In fact, 20 minutes of high-intensity interval training (HIIT) often burns no more calories than 20 minutes of moderate-intensity exercise, such as jogging.
Do you really burn more calories after a workout? Theoretically, the body continues to burn calories after an intense workout. But there are two caveats: first, this only matters during a truly intense workout. Second, after an intense workout, the body often tries to conserve calories for the rest of the day, so everything evens out while you’re lying on the couch. Even Gibala said that the “post-workout calorie burn” effect is exaggerated.
Do they help you lose weight? Diet is more important for weight loss than the amount of exercise you do, let alone the specific type of workout. Exercise can help a little in terms of calories burned (if it doesn’t make you hungry, which sometimes happens), but we’re now back to the reality that high-intensity interval training (HIIT) doesn’t offer any significant calorie-burning benefits.
Do they build muscle mass? Perhaps a little, but they won’t help you get the butt/arms/whatever you’re dreaming of. Optimize muscle growth with strength training, which requires you to lift heavy weights and then rest until you recover —usually at least one minute, often longer. High-intensity interval training (HIIT), which keeps you moving all the time or has only short breaks, may build some muscle mass, but pretty soon you’ll become so strong that the workout won’t be enough to stimulate muscle growth. To build muscle, you really need to train with progressively heavier weights .
How do you know if a high-intensity interval training (HIIT) video is actually helpful?
First, ask yourself why you’re watching this video. Do you want to improve your aerobic fitness? Then evaluate whether the exercises in the video actually leave you breathless and allow you to rest enough to repeat them. Do you want to build muscle? Then evaluate whether the video truly challenges your muscles.
As I mentioned above, sometimes we do HIIT workouts not for any specific result, but because we enjoy the movement and enjoy the moves in the videos. This is normal and good, and it certainly counts toward the 75-150 minutes of exercise you should be doing per week . But if you have specific goals, look for better ways to achieve them. There’s probably something better for you than yet another HIIT video.