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16 Benefits Of High-Intensity Interval Training (HIIT)

16 Benefits Of High-Intensity Interval Training (HIIT)

There are many different habits and workouts you can do to improve your life. What about high-intensity interval training, what benefits can you expect?

High-intensity interval training is a type of training where you do shorter bursts of more intense tempo exercise (for example 30 seconds) with slightly longer periods of less intense tempo (for example a minute or two) in between.

Generally high-intensity interval training is done with more cardio-focused workouts. Some examples of exercises that can be done in a high-intensity interval training manner are running, swimming, cycling. If you are less in shape even walking could be done in a HIIT way.

Whether a certain tempo is “high-intensity” depends more on the physical capacity of a person than on a certain speed.

Keep in mind that intense exercise like high-intensity interval training can lead to injury more easily than softer workouts. If you’re starting to exercise again after a long time it may be smarter to start out less intense and build up from there.

That being said, if your body is able to deal with high-intensity interval training adding it to your routine can offer you some of the following amazing benefits.

1. Stronger muscles

High-intensity interval training is a big category but the exercises in it can definitely help you improve muscle strength and endurance.

Even if it is the same exercise, the intensity at which you do it makes a difference in terms of working out your muscles. Take for example running, sprinting at a high speed will engage your muscles more than jogging at a low tempo.

If you are serious about building muscle you do generally want to choose weight lifting exercises over high-intensity interval training.

Extra muscle is not only beneficial for your health in many ways but it is also considered to be visually appealing.

What muscles you will work with high-intensity interval training depends a lot on the specific exercise you do. For example, HIIT with running will mostly engage your leg muscles while HIIT with swimming will also engage your upper body muscles.

2. Stronger immune system

Your immune system is a collection of biological processes that protects you from diseases.

On top of the many other benefits, physical exercise like high-intensity interval training can make your immune system stronger (1, 2, 3, 4, 5). This in turn helps you with being sick less often.

You do have to keep in mind that at some point working out can turn into overtraining which can weaken immune function. This is a valid concern if your focus is on high-intensity interval training.

3. Can help with losing weight

Losing weight is about using up body fat, which is basically energy stored. To do this you want to make sure that you require more energy throughout the day than there is coming in from food.

One way to try to make this happen is by doing a workout. By increasing the intensity of your movements for a period of time you use up more energy than usual. Doing high-intensity interval training can help with weight loss since doing a workout like it generally requires more energy than most of your usual daily activities.

As a high-intensity interval training example, 10 minutes of sprinting at 10.9 mph (17.5 kmh) can help you burn around 177-305+ calories depending on weight, intensity, and much more. This is more than a good amount of workouts burn in 30 minutes.

The actual number of calories you burn during high-intensity interval training will again depend a lot on the specific exercises in the workout.

Doing a workout at high intensity can also cause something called “afterburn”. This is basically having an increased metabolism for a while after you stop doing the exercise. On top of that high-intensity interval training can help you build some or preserve muscle mass. This in turn benefits long-term calorie-burning.

All in all, high-intensity interval training is generally a time-efficient way to burn calories.

Keep in mind that other lifestyle habits like what you eat are important when trying to lose weight no matter what exercise you do. You can work out and gain weight at the same time if your other lifestyle habits are not good.

4. Improved mood

Most people are not always completely aware of it but the physical health of the human body has a big influence on the mood and thoughts of the individual.

High-intensity interval training doesn’t just help with this by improving general health. There are inevitably many different reasons involved but one reason why exercises like high-intensity interval training benefit mental health is that they promote the release of endorphins, “feel-good” hormones (6, 7, 8, 9, 10, 11).

Besides the actual physiological changes high-intensity interval training will cause, you will likely also have positive feelings about having done something challenging that’s good for you.

5. Builds fast muscle and muscle endurance

Not all muscle is the same, it can be made of different types of muscle fibers. These different types have different properties with accompanying advantages and disadvantages.

A common categorization of these muscle fibers is “type 1, slow-twitch muscle” and “type 2, fast-twitch muscle”. Your muscle groups are not made of one or the other, they are made of a certain ratio of type 1 vs type 2 fibers. The way you train can influence this ratio (12).

The type 1, slow-twitch muscle fibers are generally more useful for longer duration workouts like jogging, swimming at a low tempo, cycling at a low tempo,… Basically activities at intensities you can do for an extended period of time.

The type 2, fast-twitch muscle fibers are generally more useful for short duration, fast body movement workouts like sprints, powerlifting, javelin throwing,… Basically activities at intensities you can only do for a short period of time.

The high-intensity intervals will help you build type 2 muscle fibers. The less intense intervals will focus more on building type 1 muscle fibers.

6. Improved cardiovascular health

Your cardiovascular system is the circulatory system inside of your body and includes heart and blood vessels. These transport many types of important nutrients, oxygen, and waste throughout your body.

When you move more intensely your body needs to transport these things, which means using your heart, at a higher rate.

Your heart is a muscle that can be trained by using it more intensely. High-intensity interval training will certainly push your cardiovascular system. If you don’t overdo it and get enough rest after this can strengthen your cardiovascular system. A stronger cardiovascular system in turn leads to a wide variety of other benefits (13, 14, 15, 16, 17).

One review of studies suggests that HIIT may be more effective for improving cardiorespiratory fitness than moderate-intensity training among children and adolescents (18). Another review of studies reached a similar conclusion but in patients with lifestyle-induced chronic diseases (19).

Do keep in mind that muscles can get injured. If you have not done any physical activity in a long time you may want to start out with low-intensity movements and build up from there.

7. Can improve athletic performance

Many sport matches and competitions involve high-intensity movements in one way or another.

Simply doing high-intensity interval training can help you improve high-intensity performance (20). This can help you get better competitive results.

Do keep in mind that strength training exercises like squats can also be helpful for improving athletic performance (21). Both combined may have synergetic effects.

8. Improved cognitive function

Another benefit of exercises like high-intensity interval training is that they can help you improve your cognitive function in a few ways. First of all, they can help with the prevention of diseases like Alzheimer’s disease (22).

Another way working out benefits cognitive function is by improving brain plasticity (23, 24, 25). Better brain plasticity basically means that you are able to learn things faster, see the connection between things faster, and remember things better.

That means that adding a high-intensity interval training workout to your routine can benefit you by improving areas like your academic performance, job performance, and much more.

9. Improved bone density

The next benefit of high-intensity interval training is that it can help improve, and prevent degeneration of, your bone density, basically the strength of your bones (26, 27, 28, 29, 30, 31).

This is helpful for avoiding broken bones. Depending on your age you may not be that worried about something like this right now. However, exercising right now can help you avoid broken bones in 40 years. The things you do today have an impact on the future.

The way many parts of your body work is that by challenging them you set in motion processes that strengthen these body parts. The same goes for your bones, by putting pressure on them you make them stronger in the long-term.

How much and which bones high-intensity interval training workouts strengthen will vary from exercise to exercise. In any case something like sprinting is likely better than jogging for bone density since you put more pressure on your bones with sprinting.

10. Lowers LDL

LDL, also known as low-density lipoproteins, is considered to be “bad” cholesterol since there are negative side effects associated with having high levels of LDL in your blood.

One of the things you can do to reduce the amount of LDL in your blood is doing workouts like high-intensity interval training (32, 33, 34, 35).

11. Time-efficient workout

Another benefit of high-intensity interval training is that a good workout session doesn’t require a lot of time. A good workout session isn’t necessarily about duration.

Training your cardiovascular system doesn’t necessarily take a lot of time out of your day. A sprinting workout can train your cardiovascular system in a shorter amount of time than a jogging workout.

Longer duration workouts can still offer benefits but this means that there is one reason less why you can’t work out.

This benefit of high-intensity interval training is especially useful if you have trouble finding enough time throughout your day to fit in a workout.

12. Healthier lungs

To move around your body needs oxygen, the more intensely the more oxygen. Your body absorbs oxygen from the air through your lungs.

By using your lungs more, thanks to workouts like high-intensity interval training, you can improve how well they work (36, 37, 38, 39, 40). High-intensity interval training will definitely engage your lungs a lot.

Improving how well your lungs function leads to benefits like improved exercise performance and getting tired slower.

13. Slows down aging

Most people think of age as the number of days, months, and years that have passed since the day they were born, this is usually referred to as their chronological age. There are also many other ways to measure “age” based on physiological factors (41).

Exercises like high-intensity interval training obviously won’t have an influence on the number of days that have passed since you were born. However, physical activity can slow down the aging in terms of how fast other measurement methods progress (42, 43, 44, 45, 46, 47).

In general these other age measurements are more accurate methods than chronological age for assessing risk on age-related diseases. Slowing these down can be a huge benefit for your health.

14. Helps against type 2 diabetes

Type 2 diabetes is a disease that involves consequences like high blood sugar, insulin resistance, and lack of insulin. These things in turn can have really bad consequences so type 2 diabetes is definitely something you want to avoid.

Exercises like high-intensity interval training can help with preventing and getting rid of type 2 diabetes through a wide variety of internal processes (48, 49, 50, 51, 52).

One small study with 12 individuals observed better glycemic control by doing “interval-walking” compared to regular continuous walking (53).

Another study with 45 insulin-resistant young women looked at the impact of a 15-week HIIT program vs a steady-state exercise program and vs a control group. They observed that the HIIT group had a significant reduction in insulin levels and body fat compared to the steady-state exercise and control groups (54).

15. Improves sleep

Good quality and duration sleep are extremely important for your physical health and cognitive function. Unfortunately, many people can do a lot better with both quality and duration.

A lot of the things you do throughout the day influence the quality and duration in some way. One of the things that can benefit sleep a relatively high amount is doing a workout like high-intensity interval training (55, 56, 57).

You do want to keep in mind that exercising too close to bedtime can have the reverse effect and mess with your sleep, especially more intense workouts like high-intensity interval training. Make sure you give your body time enough time to calm down after a workout. For most people this comes down to avoiding exercises at least an hour or two before going to sleep.

16. Regulates blood pressure

Your blood pressure is how much pressure the blood circulating in your blood vessels pushes against the walls of these vessels. This measurement is a popular way to determine how healthy your heart is.

Another benefit of working out, and thus high-intensity interval training, is that it can help you regulate blood pressure (58, 59, 60). This happens because of the influence of a variety of consequences you get from high-intensity interval training including a stronger heart, less stress, expected weight loss, and more.


While inevitably some workouts are better for some of these benefits than high-intensity interval training, it is amazing that you can get so many important benefits from adding one activity to your routine.

One thing you need to remember is that high-intensity interval training can be hard on a wide variety of body parts including your knees, heart, and back, especially if you have a lot of pounds to lose. If you are in a situation like that, walking, the elliptical trainer, or swimming at low intensities may be better choices to start with.

High-intensity interval training may also require more rest between sessions. You can for example implement 3 HIIT sessions a week instead of every day. The recommended number of high-intensity interval training sessions will vary from person to person.

Also keep in mind that consistency is a big factor for a workout plan. The more you love the exercise you do the easier it becomes to do it consistently. If high-intensity interval training is a workout you love, great. If not there are plenty of other exercises to consider that can also offer a lot of benefits.