Post-bariatric physical exercise modulates areas of the brain – 02/16/2023 – Equilibrium and Health

Physical exercises practiced by patients undergoing bariatric surgery act on areas of the brain involved in food consumption, contributing, for example, to reducing hunger or accelerating the feeling of satiety. The result, observed in a survey carried out at the Hospital das Clínicas of the Faculty of Medicine of the University of São Paulo (FM-USP), pointed to an ally in controlling the weight of these individuals.

The study showed that the physical training program started three months after bariatric surgery produces functional changes in brain networks linked to food consumption that are modified by obesity. The findings corroborate the hypothesis that exercises and bariatric surgery act synergistically in the connectivity of regions associated with cognition, reward and emotional regulation, favoring, in theory, the regulation of hunger and satiety.

According to the work, exercise increased connectivity between the hypothalamus (brain region responsible for regulating appetite and energy metabolism) and sensory areas. In addition, it reduced the link between the brain structures DMN (Default Mode Hypoconnectivity, its acronym in English for “default mode network”) and the region of the brain involved in decision-making processes, the so-called salience network (SAL), whose connectivity is increased in people with obesity.

The researchers also detected in the exercised group an increase in activation of the medial hypothalamic nucleus, associated with appetite suppression and increased energy expenditure.

“The regulation of energy consumption is governed by multiple internal and external signals. People with obesity have important dysregulations in the activation and communication of brain regions associated with hunger and satiety. In this study, we verified that physical exercise contributed with bariatric surgery in the ‘normalization ‘ of these complex networks in order to improve the central control of food consumption. When the individual is exposed to a fatty or sugary food, for example, some of these areas studied are activated and connected more intensely in people with obesity, increasing the desire to eat. We saw that the exercises counteract, at least in part, this effect”, explains FM-USP professor Bruno Gualano, corresponding author of the article published in the International Journal of Obesity, to Agência Fapesp.

The work received support from FAPESP through the research grant “Effects of physical training in patients undergoing bariatric surgery: a clinical, controlled and randomized trial” and is part of the doctorate of the first author, Carlos Merege Filho, a fellow of the foundation. Researchers Hamilton Roschel, Marco Aurélio Santo, Sônia Brucki, Claudia da Costa Leite, Maria Concepción García Otaduy, Mariana Nucci (all from Hospital das Clínicas da FM-USP) and John Kirwan (Pennington Biomedical Center, USA) also collaborated, among others. ).

Considered one of the main public health problems in the world, obesity is a chronic disease characterized by excessive accumulation of fat in the body and an important risk factor for cardiovascular, musculoskeletal disorders and, more recently, also linked to the worsening of Covid-19.

The parameter used for diagnosis in adults is the Body Mass Index (BMI), which is calculated by dividing the person’s weight (in kilograms) by height (in meters) squared. Results between 25 and 29.9 characterize an individual with excess weight and an index equal to or above 30, obesity, according to the World Health Organization (WHO).

It is estimated that, in 2030, the disease should affect almost 30% of the adult population in Brazil, one of the countries with the highest rates in the world, and about 1 billion people in total (or 17.5% of adults), according to the Atlas published in 2022 by the World Obesity Federation.

Importance

For Gualano, from a clinical point of view, research data suggest that physical exercise should be considered as an important complementary therapy aimed at improving brain functions. This could even increase the known benefits of bariatric surgery for patients, such as the reduction of cardiometabolic risk factors, preservation of muscle mass and bone health.

Since 2018, the group of scientists to which the professor belongs has been researching the topic and has already published other articles. One of them showed that physical exercise attenuates and reverses the loss of muscle mass, improving the strength and functioning of the muscles of people with obesity undergoing bariatric surgery. Through molecular analysis, it was demonstrated that physical training modulated intramuscular mechanisms capable of increasing muscle mass.

The other work pointed out that training reduced risk factors for diseases associated with obesity, such as diabetes, hypertension and atherosclerosis by enhancing insulin sensitivity, reducing inflammation and improving the health of blood vessels.

Method

The randomized controlled study involved 30 women, aged between 18 and 60 years, who underwent bariatric surgery using the Roux-en-Y gastric bypass technique, in which there is a reduction in the size of the stomach and intestinal bypass. Women are the majority in the Bariatric Surgery Outpatient Clinic of the Hospital das Clínicas of FM-USP. Adolescents or the elderly were not included.

Randomly, half of them went through the physical training and the other did not. The exercise intervention was performed under the supervision of a physical education professional for six months—three times a week (resistance plus aerobic exercise)—and started three months after surgery.

Clinical, laboratory and functional brain connectivity parameters were assessed in three stages — at baseline and then at the third and ninth month after surgery. To analyze the combined effect of the surgical procedure and physical exercise, the researchers used functional magnetic resonance imaging — an imaging technique that shows the activation of brain regions. Data collection took place between June 2018 and August 2021.

“The literature already shows that those who undergo bariatric surgery have numerous brain alterations compatible with improved control of appetite, satiety and hunger. These are brain centers that command food consumption. In this research, we saw that exercise enhances this response”, he says. Gualano, highlighting that the change in lifestyle is extremely important to maintain the benefits obtained by weight reduction for people with obesity.

Currently, bariatric surgeries can be performed on patients with a BMI between 30 and 35 with uncontrolled type 2 diabetes for more than two years; individuals with a BMI above 35, as long as they have other diseases associated with excess weight, such as hypertension, sleep apnea or hepatic steatosis (fat in the liver). For people without comorbidities, you must have a BMI above 40.

In Brazil, 311,850 bariatric surgeries were performed in the last five years, of which 14.1% were funded by the Unified Health System (SUS) and the rest by health plans or private individuals, according to the Brazilian Society of Bariatric and Metabolic Surgery (SBCBM ).

“When we do physical exercise, we know that there are a series of physiological adaptations that translate into therapeutic benefits. On the other hand, if the individual stops exercising, the gains are reversed. Our study, however, did not verify how long they last brain changes with physical exercise. It is very likely that they will decrease in intensity, even with some degree of reversal, as the patient discontinues exercise. , complete.

Among the next steps, the group intends to study the effects of combining exercise and diet with other weight loss strategies in people with obesity. Among them are the new classes of anti-obesity drugs, such as incretin-analogous peptides, which are intestinal hormones released in the presence of glucose and which signal the brain that we are fed.

In early January, the National Health Surveillance Agency (Anvisa) approved in Brazil the first injectable drug for weekly use for overweight and obesity whose active ingredient is semaglutide. Among the actions it performs in the body is the increase in the feeling of satiety and reduction in appetite, which results in substantial weight loss and improvement in glycemic control.

The article “Exercise modifies hypothalamic connectivity and brain functional networks in women after bariatric surgery: a randomized clinical trial” can be read here.