High intensity interval training (HIIT – High Intensity Interval Training) has become a fever in many gyms in the country, as it promises to “burn” more calories in a short period of time, surpassing the benefits of long-term moderate training. It is undeniable that physical exercise can promote health and improve quality of life, but to do so, it needs to be practiced well – otherwise, the damage may outweigh the benefits.
An animal study has shown that even for active individuals there can be bone damage. The research was carried out at the Laboratory of Physiology Applied to Sports (LAFAE), of the Faculty of Applied Sciences (FCA), coordinated by professors Claudio Gobatto and Fúlvia Gobatto, and was the subject of the dissertation by researcher Emanuel Elias Camolese Polisel.
LAFAE researches physiological, metabolic and molecular adaptations in different methods of individualized training, both in animals and in humans. In this study, two groups of mice – one more active and the other less active – underwent the same high-intensity individualized training. “We identified that a high stress was generated for the bone tissue and, at least for this tissue, negative results were seen for the most active group of mice”, reveals Fulvia. According to the researcher, sedentary people have been submitted to HIIT. “We believe that these cases require more care. It is necessary to be cautious with high intensity efforts, even if the individual is physically active”, he pointed out.
To compare the exercise levels in the two groups of animals, the Laboratory team developed cages larger than the usual ones. “We observed that animals that live in boxes commonly used in laboratories are quieter, move little, that is, show more sedentary behavior. Those that live in larger boxes, on the other hand, explore the environment, are more active and are able to enhance their benefits of physical exercise in relation to sedentary individuals, when subjected to the same effort. There is evidence that the individual’s initial condition affects the results obtained by physical training,” explained Fulvia.
The cages were placed on a platform with sensors. With this, it was possible to record all animal movements, day and night. “We monitored daily physical activity, carried out metabolic measurements and molecular analyzes with the animals. We observed that the most active animals showed improvement in many parameters related to quality of life, such as increased levels of calcium in the bones”, explained Fulvia. However, according to her, the bone tissue of the most active group of mice was harmed when submitted to a HIIT-like activity performed many times a week and in the long term.
Published in Scientific Reports, the study was carried out within the scope of the Graduate Program in Nutrition and Sport and Metabolism Sciences, in partnership with the Laboratory of Endocrine Physiology and Physical Exercise, at the Federal University of São Carlos (UFSCar), coordinated by Professor Wladimir Beck. The research was supported by the Foundation for Research Support of the State of São Paulo (Fapesp).