HIIT workouts

January 28, 2023

What are High-Intensity Interval Workouts (HIIT)? What are their advantages? How to do a HIIT workout correctly?

When I advise my clients to increase physical activity. The most common answer I hear is – I don’t have time, I’m so busy, etc.

Yes, I understand all this – work, romantic relationships, family, and children, all this requires attention and time.

However, it is also indisputable that physical activity can significantly improve both our performance and our physical and mental well-being.

One of the most common fitness myths is that to get a result, you have to train for hours and hard.

This is far from the case.

If your goal is burning fat, increasing muscle mass, strengthening your cardiovascular and respiratory systems, or simply relieving stress – HIIT workouts are probably exactly what you need.

What is a HIIT workout?

HIIT (High-Intensity Interval Training) is a type of interval training that includes short periods of super-intensive exercises, cyclically alternating with exercises of lower intensity. HIIT workouts have been proven to provide the same benefits as low and medium-intensity aerobic workouts, only in a much shorter time.

High-intensity interval training activates both aerobic and anaerobic metabolism.

HIIT workouts usually last only 10-30 minutes, but despite the fact that they are relatively short, their effect on improving overall health and well-being is comparable to twice as long as medium-intensity workouts.

The exercises used in HIIT workouts can be very different – running, cycling, jumping rope, or just exercises using the weight of your body, etc.

For example, HIIT training using an exercise bike may consist of 30 seconds of riding as fast as possible with maximum resistance, followed by several minutes of slow riding with low resistance. This 30-second intensive + 2-minute low-intensity stage is considered one cycle, and usually, 4-8 repetitions are performed per workout. Thus, the duration of the workout will be from 10 to 20 minutes.

No matter what exercises are used, it is important that high–intensity intervals alternate with low-intensity intervals and that your heart rate accelerates.

How to structure a HIIT workout?

One of the most important components of HIIT training is its structure – how periods of high and low intensity are organized to create the desired overload and at the same time ensure sufficient recovery.

The goal is to work as hard as possible during high-intensity intervals. Low-intensity intervals are designed to allow the body to restore energy reserves and prepare for the next high-intensity interval.

Here are the 3 most popular HIIT training structure models:

Tabata model. 20-second high-intensity period followed by a 10-second recovery period. The cycle is repeated eight times in a row – a total of 4 minutes. It seems – nothing special, right? However, if every 20-second interval is performed with the highest possible level of effort, you will feel “well done” after these 4 minutes;
30:30 model. 30 seconds of high-intensity exercise, followed by 30 seconds of lower-intensity exercises. The cycle is repeated 3 to 5 times;
30:20:10 model. In this format, the working intervals are arranged in cycles of 60 seconds – the first 30 seconds of a low-intensity period, then 20 seconds of medium intensity, and the last 10 seconds of maximum intensity.

HIIT training can use virtually any exercise and equipment – from specific professional trainers to your body weight. For example – 30 seconds of plank then 20 seconds of push-ups at a steady pace and at the end of 10 seconds of push-ups at a very fast pace.

Warm-up and cool-down

An effective HIIT workout should begin just like any other workout – with an all-encompassing warm-up consisting of muscle warm-up and/or balance exercises to ensure optimal neuromuscular efficiency (the ability of the nervous system to activate the right muscles to stabilize the body structure in all three planes of movement in order to perform the exercise as efficiently as possible).

During the warm-up, the intensity gradually increases until it becomes difficult to speak fluently. When you start to breathe heavily and sweat – you are ready for HIIT training.

Just as preparing your body for training, cooling down is also important – gradually reduce the load and allow your body, breathing, and heartbeat to slowly calm down and restore a normal rhythm. It will also help relieve muscle pain the next day.

Common mistakes

Many fitness professionals understand the basics of HIIT, but often make two fundamental mistakes that can reduce the effectiveness of training and increase the risk of injury:

Training is too hard. As a result, you get less benefit from additional oxygen intake and metabolic acceleration processes (EPOC), which can last up to 38 hours after exercise;
Too high intensity and too short recovery period. The goal, of course, is to “get out to the maximum”, however, it is also necessary to take into account the individual abilities and training experience of each person.

Pros of high-intensity interval training

During a HIIT workout, your heart rate exceeds 75% of your maximum heart rate. Therefore, if you have any problems with your heart, talk to your doctor before starting HIIT workouts.

HIIT can help reduce the risks of chronic illness

HIIT is very good at strengthening the cardiovascular system. It’s like strength training for your heart. High-intensity intervals help the heart to move blood more efficiently, thereby reducing the risk of developing heart disease.

During high-intensity intervals, the body uses anaerobic glycolysis for energy, which helps to improve carbohydrate metabolism, which, in turn, helps to reduce the risk of developing diabetes.

The intensity of HIIT workouts is very high, so during them you “burn” significantly more calories than when running, riding a bicycle, or during strength training for the same amount of time. This makes it easier for you to maintain a healthy body weight and significantly reduces the risk of obesity

HIIT can help increase muscle mass and strength

Type II muscle fibers (which use anaerobic glycolysis) are also responsible for increasing muscle hypertrophy. If type II muscle fibers have to constantly use glycogen (during high-intensity exercises), they “learn” to store more glycogen for subsequent workouts and as a result:

You have more quickly available energy and can train longer and do heavier exercises;
Glycogen molecules attract water, therefore – the more glycogen is stored in muscle cells, the more their size increases.

The “burning” of fat continues after a workout

During HIIT training, muscles use mainly carbohydrates for energy, but after training during the recovery period, fat.

In other words after a workout, energy is needed to repair muscle fibers damaged during training, and it is taken mainly from fat.

HIIT can improve oxygen consumption (endurance)

This is the ability of your muscles to use oxygen. To improve the efficiency of the use of oxygen (train endurance), long-term running or cycling sessions at a steady speed are traditionally used.

It seems that high-intensity interval workouts can improve the efficiency of oxygen consumption as much as traditional, hours-long endurance workouts.

This is also confirmed by studies such as:

HIIT may lower blood pressure

A large number of studies have shown that HIIT workouts can lower blood pressure in overweight and obese people.

It seems that HIIT can lower blood pressure even more efficiently than the often recommended moderate-intensity endurance workouts.

At the same time, HIIT does not change blood pressure in people with normal body mass index and normal blood pressure.

HIIT may reduce blood sugar levels

Studies have shown that HIIT not only reduces blood sugar levels but also reduces insulin resistance – even better than traditional exercises.

This effect has been found both in people suffering from diabetes and without it.

HIIT can help maintain muscle mass in the elderly.

Studies have shown that high-intensity interval workouts can increase mitochondrial biogenesis, and protein synthesis, and improve mitochondrial function.

HIIT causes beneficial adaptations in skeletal muscles by increasing the number of mitochondria, which can help maintain the oxidative ability of muscles and slow down the age-related decrease in muscle mass and strength (sarcopenia).

HIIT can help raise anabolic hormone levels

After a HIIT workout to restore damaged muscle proteins, the body produces human growth hormone (HGH), testosterone, and insulin-like growth factor-1 (IGF-1). Regular HIIT workouts combined with strength training can help raise the overall levels of these hormones, which can make it easier to gain muscle mass.

HIIT may reduce the risks of Alzheimer’s disease and other dementias

HIIT workouts have been shown to have a significant impact on elevations in BDNF (a protein that stimulates the growth of new brain cells) compared to medium-intensity and balance exercises.

HIIT workouts not only strengthen your muscles but can also help strengthen your brain.

Key takeaways

The main advantage of HIIT is that it provides the same effect as traditional workouts but in twice a shorter time.

However, they are not suitable for everyone, as they require very good physical fitness and can cause both physiological and psychological overload.

During a HIIT workout, the muscles of the upper and lower parts of your body work simultaneously, and you consume much more energy (“burn” more calories) than, for example, during strength training in the same period of time.

So.

Focus on workouts lasting from four to ten minutes (without taking into account the warm-up and cool-down). Challenge yourself as much as possible in each intense phase, but when the workout is over, do no more other exercises that require a lot of effort.

Some tips:

Don’t overdo it. At first, choose a rhythm familiar to you with a lower intensity;
Start with two HIIT workouts a week and two to three cycles per workout;
If you are faced with joint pain, choose more joint-sparing exercises, for example – riding a bicycle or swimming;
Rest (low intensity) periods should be equal to or longer than high-intensity periods – high HIIT intensity can only be maintained if your energy stores have recovered sufficiently;
High-intensity periods should not last more than 30 seconds if they are longer – it will be difficult for you to maintain the intensity required for a HIIT workout;
Remember – in order to avoid injury, the body needs time to recover.

Sources:

The Effects of High-Intensity Interval Training vs. Moderate-Intensity Continuous Training on Heart Rate Variability in Physically Inactive Adults

High-intensity interval training for health benefits and care of cardiac diseases – The key to an efficient exercise protocol

High-intensity interval training, solutions to the programming puzzle: Part I

High-intensity interval training, solutions to the programming puzzle. Part II

Physiological adaptations to low-volume, high-intensity interval training in health and disease

A meta-analytic review of the effects of exercise on brain-derived neurotrophic factor

Changes in mitochondrial function and mitochondria associated protein expression in response to 2-weeks of high intensity interval training

Superior mitochondrial adaptations in human skeletal muscle after interval compared to continuous single-leg cycling matched for total work

Energy compensation after sprint- and high-intensity interval training

The acute effect of exercise modality and nutrition manipulations on post-exercise resting energy expenditure and respiratory exchange ratio in women

Magnitude and duration of excess of post-exercise oxygen consumption between high-intensity interval and moderate-intensity continuous exercise