You might not be burning as many calories as you think after those HIIT sessions.
HIIT—high intensity interval training—is efficient, intense, and popular.
And there’s a reason for its popularity. HIIT workouts improve your cardio, lower blood sugar levels, and cut fat.
But there’s a lot more hype about the way HIIT burns a lot of calories. The claim is that HIIT makes your body burn more calories at rest than any other form of exercise.
If HIIT can burn more calories plus all the other benefits, it sounds like the holy grail of exercise. But the claim may be exaggerated based on what we know right now.
But first, what is HIIT?
For anyone who’s heard the benefits of HIIT workouts but hasn’t done one yet, in HIIT workouts you do short bursts of intense activity followed by longer periods of rest.
During the high intensity intervals of a HIIT workout, you give around 80% of your total effort for short periods of time. You follow up each intense burst of activity with complete rest or lower intensity effort for longer chunks of time.
As an example, one of the most popular ways to do HIIT is on a stationary bike. In a HIIT bike session, you’d do a warm-up before starting rotations of intense pedaling for 45 seconds followed by two minutes at a slower pace. 45 seconds of intense exertion is an example, not a hard and fast rule. The key is for your rest period to be twice as long as your intense intervals.
Why do people swear by HIIT?
HIIT lets you tailor your workouts to your exercise interests.
There are countless other ways to do HIIT that involve biking, running, or using weights. As long as you’re breaking up bouts of very high intensity with rest at appropriate ratios, you’re doing HIIT.
Another favorite aspect of HIIT workouts is how short they are. HIIT workouts will often range from 15-30 minutes. Which makes it perfect for anyone who has a busy schedule.
Despite how short the workouts are, HIIT burns plenty of calories during your workouts—and then some. You can burn 30% more calories doing HIIT than other workouts.
HIIT workouts require a drastically lower time commitment than other forms of exercise and produce more calorie burning and fat loss results in those shorter periods of time.
But the big question (because of all the big claims) is whether or not HIIT burns more calories after your workouts too. Will your metabolism be significantly improved for the rest of the day or longer?
Burning Calories Post-HIIT
It’s first important to point out that your body is always burning calories, even in rest.
What many exercisers care about though, is how many calories are burned at different points in the day. And how to increase their calorie burning rate.
It’s a no-brainer that you burn more calories during your workouts. That’s when you’re exerting extra energy.
But exercise also influences how your body uses energy at rest. You burn calories at a higher rate after your workouts too.
This is often called the “afterburn” effect.
The technical term is EPOC (Excess Post-Exercise Oxygen Consumption). EPOC is how much oxygen your body needs post-workout to get your body back to normal resting conditions. Your body uses a lot of energy in this process and it’s how you keep burning calories after your workout.
The reason HIIT produces such an effective afterburn is because of how intense it is. You might have those bouts of rest, but don’t let that trick you into thinking it’s easy. The “high-intensity” part of HIIT is no joke.
That high-intensity is what makes HIIT great for burning so many calories during your workout and immediately post-workout. The more intense your training is, the more energy your body uses to return to a normal state. Which is why you’ll experience more “afterburn” just after a HIIT session than a steady-state cardio or weight lifting workout.
But this doesn’t prove HIIT as the best exercise to consistently burn more calories all day.
While there’s a minor continuation of “afterburn” for up to 24 hours after exercise, most of that metabolism increase is only significantly higher soon after the workout. No matter how intense your HIIT workout was, your body isn’t burning calories at the same increased rate a full 24 hours later.
When it comes to burning more calories throughout the day, your body composition is hugely important and often overlooked when talking about exercise and burning calories.
Your body composition is the ratio of fat tissue to lean tissue. Your lean mass includes everything that’s not fat. But for our purposes we’re just concerned with muscle.
When you have more muscle your resting metabolism increases. This is because more energy is required to fuel muscle tissue. At rest, one pound of muscle tissue burns around three times more calories than one pound of fat tissue.
So if your body uses more calories to fuel muscle than fat, then the more muscle you have the more calories you burn—even at rest.
What HIIT falls short on compared to weight training is building muscle.
Weight training is still the best way to build muscle.
And if you want to raise your resting metabolism and burn more calories all day, every day, building more muscle is important.
HIIT isn’t the ultimate exercise to burn calories all day.
You’ll certainly burn a lot of calories during and after your workout, but it’s only one piece of the puzzle. Weight lifting to increase muscle mass will also increase your metabolism and help you use more calories while at rest. Even if in most cases you’ll burn more calories during a HIIT workout than during a weight lifting workout.
So if the “afterburn” is largely exaggerated and building muscle boosts metabolism even more, is that a reason to stop doing HIIT?
Not at all!
If you enjoy the workouts or if they’re best for your tight schedule—keep doing them! It’s a great way to exercise. And you will burn calories.
Just know that it’s not working any miracles when it comes to burning calories all day long.
If your goal is to burn more calories at rest, building more muscle through weight lifting is important to have in your routine. And remember that your nutrition habits are key to seeing the calorie-burning and fat loss benefits of any type of exercise.
At Lotus Fitness you can sign up for HIIT classes, muscle-building weight lifting classes, and bodyweight circuits. Training with Ewunike ensures you have all your bases covered so you can become your fittest and happiest self.
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