If you exercise consistently or at least lookup fitness information, there is no doubt that you’ve come across the HIIT acronym, which stands for high-intensity interval training.
Indeed, HIIT has been gaining a lot of popularity in recent years, and countless people talk it up as the most effective way to train for athleticism, strength, and fat loss.
But how true is that? More importantly, is there any scientific backing to high-intensity interval training?
Today, we’ll go over everything you need to know about this training protocol. More specifically, you’ll learn what it is, what benefits it offers, and how to use it to your advantage.
What Is High-Intensity Interval Training (HIIT)?
High-intensity interval training, as the name suggests, is a training protocol where you perform short bursts of intense physical activity followed by brief recovery periods. This is usually repeated several times before the workout is done.
Another common way to perform HIIT is to alternate between periods of very intense exercise (for example, sprinting) and periods of less severe activities (for example, jogging or walking).
You can do HIIT on just about every form of physical activity out there. Here are some examples:
- Lifting weights;
- Bodyweight training;
- Jump rope;
Here’s an example of a basic HIIT workout:
Activity: Interval running (70-75 percent of maximum speed)
What a round consists of: 30 seconds of interval running followed by 30 seconds of walking
Number of rounds: 10
Time for completion (not including the warm-up): 10 minutes
What Benefits Does HIIT Offer?
Granted, some eager individuals may have overexaggerated some of HIIT’s benefits. But, it doesn’t mean that high-intensity training doesn’t offer some incredible advantages:
1. Great Caloric Burn In A Short Amount of Time
Because HIIT packs a strong punch, you can expect to burn a lot of calories in as little as ten to twenty minutes of exercise.
For example, this study from 2015 set out to examine the caloric burn of high-intensity interval training in comparison to aerobic and resistance exercise of the same duration. Researchers found that HIIT burned up to 30 percent more calories than the other two modalities.
The HIIT protocol was pretty standard: 20 seconds of all-out effort followed by a 40-second recovery period.
This is quite logical because the HIIT group (though they experienced fatigue and a drop in their performance) did significantly more work in that 30-minute workout.
2. Caloric Burn For Hours After The Workout Is Done
Most physical activities burn calories only while they last. But, high-intensity interval training allows us to expend a small number of calories in the hours after we’re done exercising.
Granted, this benefit has been greatly exaggerated, and some folks claim outrageous numbers. Even with the smaller amounts, the benefit is still there.
This paper from 2006 did a great job of looking at the existing literature and coming up with a conclusion. In it, researchers concluded that EPOC (excess post-exercise oxygen consumption) results in an extra 6 to 15 percent calories to be burned after exercise. They also suggested that steady-state cardio leads to an EPOC of about seven percent, and HIIT can approach double that - about 14 percent.
So, if you run on the treadmill for an hour and burn 450 calories, you can expect to burn an extra 31 calories afterward. On the other hand, if you do an intense 20-minute HIIT session, you can expect to burn 450 calories, and an additional 62 in the hours after that.
It’s not a large caloric burn, but keep in mind that these are extra calories you get to burn without doing anything.
3. It Can Aid In Muscle Growth
Thanks to the high intensity and dynamic nature of HIIT, this exercise modality can aid in muscle growth.
For example, one paper from 2016 found that performing sprints and combining sprints with some resistance training led to much greater lean mass gains in the lower body than endurance training did.
Unlike traditional cardio, HIIT can be done in specific ways that promote muscle gain:
- Sprinting and interval running have both been shown to aid in lower body muscular development;
- The battle rope is a great activity to develop your shoulders, arms, and upper back;
- Doing intervals on the rowing machine is an excellent way to add size to your back, arms, and core;
- Bodyweight training is also a great way to build muscle;
4. It Can Be a Valuable Tool In a Fat Loss Plan
This particular study examined the caloric burn of:
- HIIT performed on a hydraulic resistance system - an average of 12.6 calories per minute;
- Weight training - an average of 8.8 calories per minute;
- Jogging on a treadmill - an average of 9.5 calories per minute;
- Cycling - an average of 9.2 calories per minute;
Meaning, when compared over a 30-minute workout, if the HIIT protocol burned a total of 378 calories, then the other three modalities hovered somewhere around 273 calories - over 100 less in the same period.
And, since being in a caloric deficit is the most important thing for fat loss, picking an activity that burns more calories will more than likely deliver better results.
How To Do High-Intensity Interval Training: 4 Solid Ideas
You can do HIIT in many ways, but the below four are among the most versatile, fun, and effective ones:
1. Using Cardio Equipment
When most folks think of cardio equipment, they imagine mundane jogging or cycling that seems endless. But, cardio equipment can very much be used as a tool for HIIT.
Even if you have a home gym, it’s worth visiting a commercial gym for the high-end cardio equipment because quality is costly. A decent treadmill or elliptical can easily be in the thousands of dollars.
Good examples of cardio equipment for HIIT are the elliptical, a stationary bike, a treadmill, and a rowing machine.
For example, you can perform a HIIT workout of five to six rounds, with each round becoming more challenging on a stationary bike:
Round 1: 25-second all-out effort followed by 90 seconds of recovery
Round 2: 27-second all-out effort followed by 90 seconds of recovery
Round 3: 29-second all-out effort followed by 90 seconds of recovery
Round 4: 31-second all-out effort followed by 90 seconds of recovery
Round 5: 33-second all-out effort followed by 90 seconds of recovery
Round 6: 35-second all-out effort followed by 90 seconds of recovery
The entire workout will be done in about twelve minutes, not including the warm-up and cooldown.
2. Bodyweight Training
The greatest benefit of bodyweight training is that you can do it almost anywhere with zero equipment. Plus, research suggests that bodyweight training can be quite practical for muscle and strength gain. So, why not take advantage of it?
What’s even better is that you don’t need much space, these workouts burn a ton of calories, and they train your entire body.
Let’s take a look at an example bodyweight HIIT workout you can do. This workout consists of seven exercises, each emphasizing a specific portion of your body. The goal is to perform all activities back-to-back then rest for a couple of minutes. This will be one round. How many rounds you choose to do will depend on your ability, goals, and schedule.
12-20 push-ups of your choosing
40 total high knees
12-20 bodyweight squats
60-second plank hold
60-second jumping jack session
20 total forward lunges
3. Jump Rope
Jump rope is among the best all-in-one activities to build muscle, become more athletic, lose fat, and become more coordinated. What’s better, jump rope offers a killer workout in less than twenty minutes.
Here’s an example, and remember to warm-up well beforehand:
20-second double unders (jumping a bit higher and swinging the rope twice underneath your feet before you land) followed by 20 seconds of rest
You can repeat this round for as many times as you’d like. And, once double unders become too easy, you can start doing 25 or even 30-second bouts.
4. Sprints and Intervals At The Track
Sprints and interval running are both great ways to do HIIT. For a beginner, intervals are the better option because sprints are more demanding, and the risk of injury is a bit higher.
Here’s an example interval running workout:
30-second interval running (about 70 to 80 percent of your maximum) followed by 30 seconds of walking.
Repeat this whole sequence six to ten times. The entire workout, not including the warm-up and cooldown, will take you no longer than ten minutes.
Here’s an example sprint workout:
10-second sprint (all-out effort) followed by 60 to 90 seconds of walking.
Repeat six to ten times.
For best effect, and to prevent overtraining and overuse injuries, do no more than three HIIT sessions per week, spaced at least 48 hours apart.
The Bottom Line
HIIT is among the most effective ways to exercise and reap all of the benefits without having to invest hours upon hours every week. What’s more, you can do HIIT in numerous ways, even if you don’t have access to any gym equipment.
This training modality not only does a great job of bringing about all of the health benefits associated with exercise, but it also makes us stronger and more athletic. Plus, it burns a lot of calories, which makes it a great fat loss tool. And, finally, HIIT provides a strong stimulus to our muscles which helps develop them and retain them better while dieting.
When done correctly, HIIT is the best option for busy folks looking to get (and stay) fit.