Understand what HIIT is, training that brings physical conditioning faster

HIIT, from English “high intensity interval training”, is a training method popularized in gyms for offering improvement in physical conditioning in less time. There was also a promise that it would burn calories faster, but there is no scientific consensus.

The method consists of short-term training, with intervals between high and low intensity activities. In one part, the heart rate can reach its maximum limit, while in others, with half the time or the same duration, the exercises are performed at a lower intensity or the individual can even recover while standing, explains physical educator Fúlvia Gobatto. , professor at Unicamp (State University of Campinas).

For example, someone does one minute of intense jogging and then walks for 30 seconds. “It’s a very old workout, which was originally practiced by professional athletes, but has spread to different populations. HIIT can be used with any type of cyclic activity, such as swimming, running, cycling and rowing”, says Gobatto.

With shorter sessions, HIIT brings benefits to the body by causing physiological changes. To recover after exertion, the body expends energy at rest to restore its proper conditions.

And the shorter duration makes it easier to fit into everyday life. Therefore, HIIT is an option for those who have a busy routine, but want to get out of a sedentary lifestyle.

“I believe that the biggest benefit is the faster change in cardiorespiratory fitness”, says physical educator Valéria Panissa, professor at EEFE-USP (School of Physical Education and Sport at the University of São Paulo).

This is explained by the greater consumption of oxygen in the sessions, which leads the individual to improve their physical conditioning in advance. Research shows its benefits in cardiac rehabilitation.

In an investigation published in Jama Cardiology, scientists compared the effectiveness of high-intensity interval training with moderate, long-duration exercise in patients with coronary artery disease.

The HIIT was done with four sprints of four minutes each, with intervals of three minutes. Moderate exercises were performed in 40-minute sessions. In both cases, the activities were practiced three times a week.

After four weeks of monitoring the volunteers, the authors found that the high-intensity method increased their breathing capacity by 10%, while the other group experienced an increase of only 4%.

A review of studies, published in the journal of the Sports Medicine Society of Australia, showed that HIIT increased the ability to absorb oxygen more during physical activity compared to exercise of longer duration and less intensity.

The study considered studies with healthy adults as well as obese and overweight and in both cases high-intensity training was superior.

“For the general population that is in need of an improvement in health, he anticipates this good conditioning. The person sees improvement in a short time, such as feeling less breathless to climb a ladder, for example”, says Panissa.

Does it help you lose weight faster?

When it comes to weight loss, there is still an imbroglio among scientists. Panissa says that until recently, studies linked HIIT to greater caloric expenditure and weight loss compared to moderate physical activity. “But new, more controlled research was coming out and today we know that this is not true”, contextualizes the researcher.

Gobatto reports that this is still not a consensus in the academic environment. According to her, scientists realized that when comparing the energy expenditure of high-intensity interval exercises with longer moderate sessions, they made a false equivalence.

“As HIIT is a puzzle that can be manipulated in different ways, to make this comparison we have to look at the intensity in the highest stimulus, how long the person was there, the intensity they were on break and add all that”, explains the researcher. In other words, older studies did not take into account the nuances of the method when making the comparison.

Research published in 2017 in the scientific journal of the World Obesity Federation reviewed 28 papers comparing the two methods over four weeks. The authors found that there was no difference in caloric expenditure and mass loss between them.

Another study, published the following year in the same journal, looked at the effect on people who were overweight or obese and came to the same conclusion.

On the other hand, a new review of 18 controlled trials published in the British Journal of Sports Medicine compared HIIT practice with moderate exercise over 12 weeks. The analysis revealed that each minute of high-intensity interval activity burned 0.13 grams of extra fat.

care when practicing

Those who want to start this type of training should take the same precautions as any other physical activity, especially if they are sedentary: consult a doctor in advance and seek follow-up from a physical educator.

Panissa points out that those with joint problems or who are overweight may have a harder time performing due to the high intensity.

“For individuals who are not used to it and even those with chronic diseases such as obesity, heart disease and diabetes, the stimulus needs to be gradual and the disease must be controlled”, adds Gobatto, from Unicamp.

HIIT sessions should be spread out throughout the week and be done two to three times a week. In this way, the practitioner runs less risk of inflammation and injuries.