Results of an online survey of 938 Brazilians who contracted covid-19 show that the prevalence of hospitalization for the disease was 34.3% lower among volunteers considered “sufficiently active”, that is, those who practiced weekly before the pandemic. 150 minutes of moderate intensity aerobic physical activity or 75 minutes of high intensity.
The questionnaire was answered between the months of June and August by individuals of both sexes and different ages who had their SARS-CoV-2 infection confirmed by the molecular test (RT-PCR, which detects viral RNA in the acute phase) or serological (which detects antibodies against the virus in the blood). Of the total participants, only 91 (9.7%) needed to be hospitalized. The complete data of the study, which was supported by FAPESP (São Paulo State Research Support Foundation), were published on the medRxiv platform, in an article still without peer review.
To define the “sufficiently active” criterion, the researchers used the World Health Organization (WHO) recommendations for adults between 18 and 64 years as a reference – which, in turn, are based on the guidelines of the main medical entities in the world.
“We sought to assess whether there was any reduction in the prevalence of hospitalization also among those who practiced physical activity for a shorter period than recommended, but in this case the difference was not statistically significant,” says Marcelo Rodrigues dos Santos, from Agência FAPESP. postdoctoral fellow at the Faculty of Medicine of the University of São Paulo (FM-USP) and creator of the research.
The questionnaire had questions about the clinical condition (symptoms, medications and, in the case of those who were hospitalized, length of stay) and other factors that could influence the outcome of the infection, such as age, sex, body mass index (BMI), preexisting diseases, socioeconomic conditions, education, tobacco consumption and level of physical activity.
The responses were analyzed using statistical models and, as expected, the prevalence of hospitalization was higher among men, the elderly (65 years or more), obese or overweight volunteers and those with lower socioeconomic status and less education. However, even after discounting the influence of these risk factors on the final result, it was possible to observe a 34.3% reduction in the prevalence of hospitalization in the “sufficiently active” group.
When comparing only volunteers who needed to be hospitalized, the level of pre-pandemic physical activity did not provide protection in terms of length of stay, symptom intensity and the need for oxygen supplementation or intubation.
“As this is an observational study, we have not investigated the mechanisms involved in the protection provided by the practice of physical activity. But there is robust evidence about the benefits of exercise for immunity. A single session can mobilize billions of defense cells, reintroducing them into circulation, ”says Santos.
In addition, as highlighted by the authors in the article, the practice of physical activity helps to control weight and prevent chronic diseases, such as diabetes and hypertension, considered risk factors for the worsening of SARS-CoV-2 infection.
When COVID-19 arrived in the Americas, Santos had just moved to Boston, in the United States, where he would start a research internship at Harvard University with support from FAPESP.
The aim of the project is to try to reverse the effects of aging and degenerative diseases through interventions capable of restoring in cells the concentration of a coenzyme known as NAD (nicotinamide adenine dinucleotide), which participates in several important biological processes. Several studies have already shown that NAD levels decrease with aging and that this decline is related to the development of metabolic disorders, such as obesity.
“The proposal is to test in obese or overweight patients the effect of a new supplement supposedly capable of enhancing the action of NAD. But when the COVID-19 cases exploded, everything closed and the investigation was temporarily halted. It was then that the idea of ??doing an online research in parallel came up ”, says the researcher.
Santos articulated with colleagues in the area of ??Physical Education from several Brazilian states, who helped publicize the link to the questionnaire in hospitals, clinics, newspapers and social networks. Researchers from the Federal University of Minas Gerais (UFMG), Hospital de Clínicas de Porto Alegre (RS), Federal University of Rio Grande do Sul (UFRGS), State University of Rio de Janeiro (UERJ) and the School of Physical Education participated in the initiative and Sport at USP.
“It was a kind of multicenter study, only online,” comments Santos.
O artigo Physical Activity Decreases the Prevalence of COVID-19-associated Hospitalization: Brazil EXTRA Study www.medrxiv.org/content/10.1101/2020.10.14.20212704v1.full.pdf.