University of São Paulo: In experiment, benefits of exercise in cyclists outweighed negative effects of pollution

Tests carried out on cyclists in São Paulo suggest that the benefits of exercise are able to outweigh the negative effects of exposure to pollution on city streets. The simulations were carried out by researchers from the School of Physical Education and Sport (EEFE) at USP in a closed environment, based on a race against the clock, in which the cyclist needs to complete a course in the shortest possible time. The circulating air was controlled as to whether or not it was exposed to gases from polluting particles. The research found that the greater amount of pollutants did not change the sports and physiological performance of the participants. These results indicate that being exposed to pollution may not be a limiting factor for physical activity.

The study is described in the article Effects of air pollution exposure on inflammatory and endurance performance in recreationally trained cyclists adapted to traffic-related air pollution published in the American Journal of Physiology on June 1st.

“Ten cyclists, classified as recreationally trained based on data obtained from a maximal oxygen consumption (VO2) test, were analyzed. Each of the volunteers made five visits to the laboratory”, reports physical educator and researcher André Casanova Silveira, who did the research during the production of his doctoral thesis at EEFE , to Jornal da USP . “The time trial was performed in a simulated way. We used a system where the volunteer’s bicycle was attached to a cycling roller with a computer linked to a program that mimicked a circuit with 50 laps of a kilometer (km).”

“The general objective of the research was to analyze whether pollution would have any detrimental effect on performance in a predominantly aerobic physical activity of long duration, in this case, a 50 km race against the clock , in trained cyclists and residents of the city of São Paulo” , points out the researcher. “Through collaboration with Professor Paulo Saldiva, from the Faculty of Medicine of USP (FMUSP), we had access to an experimental model, a container prepared with filters capable of preventing the entry of gases and particles, creating a controlled environment, including variables such as temperature and relative humidity. We evaluated two scenarios, the ‘real’ pollution from the site entering the container or the filtered condition, where the filter system decreases the amount of pollutants entering the environment”.

The container was located on the premises of FMUSP, near the corner between Rua Teodoro Sampaio and Avenida Doutor Arnaldo, in the West Zone of São Paulo. Pollutants at this point are mainly from vehicle traffic, whose daily estimate is 83,941 cars, 9,936 diesel-powered vehicles (buses and small trucks) and 808 motorcycles.

A study with cyclists was carried out in a container installed at the Faculty of Medicine of USP (FMUSP), in the West Zone of São Paulo, a region with intense vehicle traffic; The installation was equipped with filters capable of preventing the entry of gases and particles, allowing the evaluation of two physical activity scenarios, with pollution entering the container and with filtered air – Image: provided by the researcher

The research evaluated physiological factors such as heart rate, blood pressure and blood parameters (p02, pCO2, O2 saturation). “The subjective perception of effort was also analyzed, which is regulated by both these physiological and psychological factors, being a determining factor for sports performance. In addition, we analyzed the main inflammatory markers (IL-6, IL-10 and CRP) and the neuroplasticity marker (BDNF)”, reports Silveira. “Inflammatory markers are substances produced by immune system cells in response to some system aggressor. BDNF is produced mainly by brain cells and is an exercise-induced factor related to cognitive, memory and learning improvement.

exercise benefit
According to the educator, some research has suggested that the increase in BDNF induced by exercise is suppressed in a polluted environment. “This is contrary to what we observed in this study,” he explains. “However, these other works did not use trained people and did not have a controlled environment in which to carry out the experiments.”

In animals, more intense physical training stimulates blood vessel formation and oxygen diffusion in the muscles
“Our main findings in the study demonstrated that parameters related to sports performance, as well as physiological and inflammatory indicators, were not altered in people trained during exercise in an environment with low air quality”, highlights the researcher. “However, the polluted environment led to an increase in BDNF compared to the clean environment, which could indicate that the beneficial effects of exercise may be evident in trained people even exposed to poor air quality.”

According to Silveira, the research results suggest that exposure to air pollution may not be a limiting factor in the performance of cyclists who reside and train in polluted environments. “Data in the literature analyzing trained people used to training in a polluted environment are scarce,” she says. “However, based on our study and on research with animals that were able to observe both training and exposure to pollutants in a controlled and chronic way, it seems that in the long term the beneficial adaptations promoted by exercise can overcome the deleterious effects caused by pollution. ”

Silveira’s work was guided by Professor Rômulo Bertuzzi, from the Aerobic Performance Study Group (Gedae) at EEFE, with the participation of researcher Júlio Hasegawa. The research also had the collaboration of professors Paulo Saldiva, Monique Matsuda and Monica Marquezini, from FMUSP, Adriano Eduardo Lima da Silva, from the Federal Technological University of Paraná (UFTPR), Ramon Cruz, from the Federal University of Santa Catarina (UFSC), Michael Kohele, from the University of British Columbia, and Luisa Giles, from the University of Fraiser Valley, British Columbia, both in Canada.

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