Alex Shaw

HIIT – Fast But Challenging Way To Be Fit And Healthy

HIIT is the workout that can shorten your way to strong health.


High-intensity interval training is nothing new to the world of fitness. Since the beginning of the 19th century, elite athletes have used this training method to achieve great victories. Paavo Johannes Nurmi, a Finnish middle and long-distance runner who has set 22 world records and won nine Olympic gold medals, used the concept of interval training in his running sessions. In the past, HIIT was mostly connected to cycling or running. Today’s HIIT goes far beyond that, with people adapting the concept of high-intensity interval training to almost every type of physical activity, beginning with plyometric exercises and ending with strength training.

HIIT – What is it?

High-intensity interval training It is a training method that combines periods of high-intensity work with brief periods of rest. The main difference between HIIT and other types of training is the emphasis on maximum effort and short rest periods. In just ten minutes of this type of training, your heart rate will increase dramatically, and you will feel out of breath. Also, HIIT will make you sweat much faster than a typical jog or bike ride. Though there is no strict HIIT session duration, a HIIT workout usually lasts less than 30 minutes because it is difficult to perform exercises with maximal effort and such short rest periods for an extended period of time without harming your body.

HIIT Examples

Some of the best examples of HIIT are training programs such as Tabata, CrossFit, or boxing.

  • Tabata is a workout that lasts only 4 minutes. But during these four minutes, you need to perform eight intervals of 20 seconds of maximal intensity followed by 10 seconds of rest. Maximal intensity means that you need to pick only those exercises that will maximize your heart rate as much as possible (like burpees) for your Tabata training.

  • Another great example of HIIT is CrossFit, especially the so-called WOD. In CrossFit, WOD stands for “Workout of the Day.” Each WOD has a specific aim in mind, such as lifting as much weight as possible, moving as quickly as possible, or performing as many reps as possible. All of the exercises in a WOD are high-intensity, and the workout should be completed as fast as you can. As a result, the CrossFit “Workout of the Day” is an excellent HIIT because it meets the basic demands of high-intensity interval training; it consists of high-intensity exercises and has only brief periods of rest.

  • Boxing matches are another excellent example of what high-intensity interval training is and how it should be performed. Each boxing round is three minutes long, with only one minute of rest between rounds. And each round is repeated until there are a total of 12 rounds.

In fact, the majority of training can be done in HIIT style. For example, just add some short sprint intervals to your jog to transform a simple run into a HIIT workout.

Benefits that HIIT can give you

1Burns belly fat effectively

Both low-intensity steady-state cardio and high-intensity interval training can effectively burn belly fat. But HIIT is a more preferred option. Why? That’s because HIIT workouts cause your body to produce up to 450 percent more human growth hormone (HGH). And low human growth hormone secretion may also contribute to abdominal fat gain, according to research.

2Builds muscles and strength

With HIIT workouts, you not only lose fat but also build muscles. For example, high-intensity interval training can involve muscle-building movements like squats and push-ups. Also, this type of training leads to better muscle endurance due to the short periods of rest between exercises. This means that your muscles will not only grow but also be able to endure longer and more intense training sessions. Scientists have proven that substituting regular, high-volume aerobic exercise with low-frequency HIIT can lead to increased muscular strength in men. For example, in a 2017 study, scientists discovered that HIIT resulted in a 9.7–12.2% greater increase in peak power output in men than in moderate-intensity training.

3May help your brain perform better

Scientifically, it has been proven that people who exercise have higher volumes in the areas of their brain that affect thinking and memory than people who do not engage in physical activity. And recent studies on high-intensity interval training show just that. Research published in 2019 found that interval training may increase blood flow in the brain, which is associated with better executive functioning and attention.

4Your mental health also receives a bonus

It’s not a secret that regular exercise and physical fitness can improve mental health. Moreover, physical exercises have long been considered an effective method of dealing with certain conditions, such as depression. A review published in the Journal of Affective Disorders confirms that HIIT improves mental health outcomes among people with mental illnesses and can even be used as an option for therapies for different mental disorders.

A 2022 review that was published in the “British Journal of Sport Medicine” also showed the positive impact of high-intensity interval training on mental health. When compared to the non-active population, people who were involved in HIIT had modest improvements in mental well-being, depression severity, and perceived stress. And even if compared to the active population that engages in regular exercise, the HIIT group still had minor gains in mental well-being.

5The most time-efficient way of training

In our fast-paced world, time is always a crucial factor. In our 24 hours a day, we have to manage an infinite number of things. With work, family, children, hobbies, and that desired 8 hours of sleep, sometimes there is no time left for a sufficient workout. Short high-intensity interval training can produce the same (or even better) results as long low-intensity training in a much shorter period of time.

According to one study, one and a half hours of interval training are equivalent to five hours of endurance training in terms of health benefits. Meaning that you need much less time to achieve benefits for your health.

6HIIT might improve your metabolic health including insulin resistance

According to a study with over two thousand participants, HIIT not only lowers blood sugar but also improves insulin resistance better than regular, continuous exercise. In this study, participants at risk of or with type 2 diabetes had lower fasting glucose levels after high-intensity interval training compared to the group that was doing continuous training. Based on this evidence, high-intensity exercise may be especially useful for improving metabolic health, particularly in people at risk of or already suffering from type 2 diabetes. However, a comparison of high-intensity interval training and moderate-intensity continuous training in healthy people suggests that HIIT may be effective at improving insulin resistance in a healthy population as well. In particular, this study shows that after 8 weeks of training, insulin resistance decreased only in the HIIT group.

HIIT. Experiment by our expert

We introduce one of our Healthypedia personal testers. Michael Freeman is a big health enthusiast, in a great shape in his 50, and metabolically healthy! Michael uses a monitor which measures reaction of his body on food, exercises, stress, you name it. Here is his feedback and result.

Exercise test
It was pretty interesting to see the reactions of my body to high-intensive exercises like CrossFit, which I do at least 3 times a week. Disclosure. I don’t have meals 2 hours prior to training, during training and after training. Just water and an intense workout. There was a huge blood glucose Everest-like spike during the 30 minutes after the most intense part of the training. But from a health perspective, it is a completely different result compared with food consumption check-ups. Totally opposite! The body requires huge volumes of glucose to perform. If all glucose stored in muscles and the liver is depleted, the body starts to utilize fat at an enormous capacity for its energy purposes. When it cannot stop doing this during 30-60 minutes after your exercise this leads to fat loss. This is a fantastic result and excellent confirmation that HIIT (High-Intensity Interval Training) is one of the best things you can do for your health. Not only for muscles but for metabolic processes and weight management as well. While you lose fat, you train your body to use your fat storage for energy at a very large speed and volume.
Michael Freeman
Health and Longevity Enthusiast, 50

7It’s convenient and not expensive

HIIT does not require much equipment. You can easily begin high-intensity interval training by using only your body weight. Furthermore, as your fitness level improves, you don’t need to add extra weight to increase the intensity of your HIIT workout; you can simply reduce the rest time between exercises. HIIT also does not require a lot of space, as you can easily do exercises like burpees or jumping jacks at home. Because of this, high-intensity interval training is an excellent choice for a home workout. And home workouts can save you a lot of time and money.

HIIT downsides

If your objective is to enhance your health and fitness, too much high-intensity interval training might backfire. While a bit of HIIT might give you a lot of benefits, doing so for lengthy periods of time can overstress your body. Because of the high intensity, it’s easy to overdo this type of training and end up with more harm than benefit.

It’s a challenge

Training must be done on a regular basis in order to have a positive effect. Because of the intensity, it may be difficult for someone to perform high-intensity interval training consistently. Even high-intensity sprints of about 15 seconds are going to challenge us a lot. It’s not even worth mentioning how difficult such high-intensity work will be for 15 minutes, even with the fact that we will have short breaks during these 15 minutes. Not everyone can maintain this level of intensity during their workouts on a consistent basis.

You have a higher risk of injury

High-impact motions, such as burpees and jump squats, can place additional strain on your joints and increase your risk of pain and injury. In 2019, The Journal of Sports Medicine and Physical Fitness published a review in which they estimated injury incidence related to exercises such as burpees, push-ups, and lunges. Scientists discovered that injury levels increased significantly during a period of increased interest in high-intensity interval training.

To avoid injuries during HIIT, always perform a proper warm-up before the workout session. Perform dynamic stretching for all of the muscles that will be involved in your workout. Also, if you are doing some exercise and it causes you pain or discomfort, stop doing it right away. Exercise through pain will certainly lead to injury. And after you finish a workout, do some static stretching to allow your muscles to recover from the high loads. A proper warm-up and cool-down will significantly reduce the risk of injury.

If you are injured, a HIIT workout is not recommended. HIIT exerts a lot of strain on your muscles, joints, tendons, and ligaments, and if you already have an injury, training at a high intensity will only worsen your condition.

It takes more time to recover

HIIT is difficult. This is both an advantage and a disadvantage. It takes longer to recover from a HIIT workout, so due to the physical demands, it may be difficult for your body to recover if you do a HIIT workout every day. Not giving yourself enough recovery time can lead to decreased performance, weakened immune systems, exhaustion, and chronic joint and muscle pain. Moreover, when you exercise at a high intensity, you release cortisol, the stress hormone. And if your body is continually stressed, it can cause a variety of undesirable side effects, such as digestion troubles, bloating, and weight gain.

Not for people with heart diseases

Your functioning muscles require extra oxygen while practicing HIIT. Your body has to work harder to transfer oxygen, putting a strain on your heart and cardiorespiratory system. And that extra pressure on the heart may raise the risk of certain heart diseases, particularly in people who already have them. It’s better to consult with your doctor about whether this type of workout is suitable for you, especially if you have had heart disease in the past.

How to start HIIT the right way

A mindful approach is the best approach, which is especially relevant when it comes to high-intensity training. So make sure that you’re doing your training the right way and don’t let mistakes ruin your gains.

Common sense when you start is the best way to start doing HIIT.

Choose the right volume of HIIT training

If you’re new to HIIT, start slowly with one to two sessions per week lasting 10 to 20 minutes. Stay with this volume of training for a few weeks before moving on. When your fitness level has increased, you can then move to two to four sessions of 10 to 30 minutes of HIIT per week.

Slowly increase the intensity

When you’re starting HIIT workouts, don’t rush the intensity and don’t put too much pressure on an unprepared body. Make your rest periods longer than your work periods. By doing this, you get good recovery between exercises, which will allow you to be efficient throughout the whole workout. Work periods can be gradually increased as you progress. Also, if you start doing HIIT, instead of choosing the hardest exercises, choose exercises that suit your fitness level. For example, if classic burpees are too hard for you, start with half-burpees or burpees without a jump. Over time, you will progress and be able to make advanced variations of each exercise. A mindful approach to HIIT workouts is to gradually increase the intensity.

Prepare your body for tension

HIIT is strenuous and it’s not a good idea to hit the max effort from the very beginning of the workout. It’s best to begin with a few less strenuous exercises as a warm-up, or with easy variations of the exercises you’ll do during your workout. If you don’t get a proper warm-up, it’s more likely that you may have an injury during the workout. And if you get injured, you won’t be able to do any type of training, so it will take even more time to reach your fitness goals.

Let’s sum HIIT up

High-intensity interval training is one of the most effective ways to achieve your fitness and health objectives. It can help you burn fat, gain strength, and improve your mental and metabolic health. Plus, compared to long and boring cardio sessions, with HIIT you’ll achieve benefits for your health in much less time.

Hungry for knowledge? Here is more!

Check out this video from the GTN YouTube channel that includes variations of HIIT training with different intensities. This video is good for both beginners and more advanced trainees.

Also take a look at this video, in which Thomas DeLauer tells us about the unexpected benefits that you can get from high-intensity interval training. Thomas DeLauer has made a reputation for himself by assisting people in finding the time to make tiny, simple adjustments in their diets and habits in order to become healthier.

Healthypedia FAQ

High-intensity interval training (HIIT) is a training method that involves alternating short bursts of vigorous anaerobic activity with brief intervals of rest.

When done correctly and in the appropriate amount, HIIT is safe and has no negative effects. However, if you have a history of heart illness or injuries, you should check with your doctor to see whether you can undertake this activity.

The quantity of HIIT exercise advised depends on your fitness level, but for beginners, one to two sessions per week lasting 10 to 20 minutes would enough.

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