A study conducted at Universidade Estadual Paulista (Unesp) indicates that even mild to moderate infection by Sars-CoV-2 can cause an imbalance in the cardiovascular system of young adults without preexisting diseases. The research also concluded that both obesity and a low level of physical activity are determining factors in the post-Covid-19 period that help to change the autonomic nervous system, responsible for vital body functions, such as blood pressure, heart rate and respiratory rate.
The work, which was supported by FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo), followed individuals between the ages of 20 and 40 before being vaccinated.
“These results give us elements to encourage people, even with mild symptoms of Covid, to seek a more thorough diagnosis after contamination. The baggage triggered by the virus can have consequences and the patient does not know”, evaluates the project coordinator, Professor Fábio Santos de Lira, from the Department of Physical Education of the Faculty of Science and Technology of Unesp, Presidente Prudente campus. He is one of the authors of the article published in International Journal of Environmental Research and Public Healthin the special edition Impact of Lifestyle Interventions in Immune Response, Inflammation and Vascular Health.
The research is part of a broader project, FIT-COVID, which aims to investigate gaps in scientific knowledge about the disease with a specific focus on immunological, inflammatory and metabolic markers, exploring the temporal modulatory effects of physical activity and composition. body.
For the study, the researchers recruited patients infected with Sars-CoV-2 in Presidente Prudente, a municipality in the interior of São Paulo with about 231,000 inhabitants and which, by the end of February, had recorded 39,049 confirmed cases of Covid-19 and 982 deaths.
Subjects had a diagnosis confirmed by RT-PCR test and infection with mild to moderate symptoms. A healthy control group was age matched. In total, 57 people were evaluated, but after the exclusions, 38 were considered in the final result.
The body mass index (BMI, parameter used to assess overweight and obesity and which corresponds to the ratio between weight and height squared) and physical activity levels (using a triaxial accelerometer) were measured, in addition to the assessment of the nervous system. autonomous through heart rate variability.
The main finding was that, even in mild and moderate infections, young adults infected with Sars-CoV-2 showed: greater sympathetic activity (a system that adjusts the body to withstand situations of danger, intense effort and stress); less parasympathetic activity (responsible for making the body calm down after a stressful situation); and global variability when compared to uninfected individuals. That is, in the post-Covid group, there was an increase in heart rate and less activity of the body to “stop” this frequency.
When comparing overweight and obese and/or physically inactive individuals, cardiac autonomic modulation showed worse indices. Thus, the results provide new insights on the role of BMI and physical activity in post-Covid-19 infection dysregulation that may contribute to the understanding of the pathophysiology and treatment of later acute symptoms.
“We did not expect such an altered cardiovascular system because they are young and without other diseases. Our work shows that people infected by Covid, even without severe symptoms, can present important functional changes. For example, this variation in heart rate may, in the future, become an arrhythmia”, says the postdoctoral student at Unesp Luciele Guerra Minuzzi, one of the researchers who participated in the article together with the first author, Ana Paula Coelho Figueira Freire, from Universidade do Oeste Paulista (Unoeste), and with Bruna Spolador de Alencar Silva, also a postdoctoral fellow at Unesp and one of the coordinators of the project.
The reflection of these variations was recorded in the patients’ daily activities, such as the ability to exercise, climb stairs and even walk. They reported tiredness and fatigue. To detect the problem, you can do a simple test known as the six-minute walk test.
In a study by Unesp, people who had Covid-19 reported tiredness and fatigue after exercising, climbing stairs or walking (Photo: Ev/Unsplash)
According to Minuzzi, the group had already shown metabolic deregulations – such as a higher concentration of lipids in the bloodstream and altered blood glucose – in patients with Sars-CoV-2 who had more severe conditions and were hospitalized.
Another study published in August 2021 by scientists at Appalachian State University in North Carolina (United States) found that young adults recovering from Covid-19 had autonomic dysregulation. However, the work used an invasive method, while the Brazilian research adopted a simpler, cheaper and non-invasive form of evaluation.
At the time, the conclusion was that there was a prolonged physiological impact of SARS-CoV-2 infection, lasting two to three months, on resting heart rate, which may reflect autonomic dysfunction. The findings were attributed to the increased state of inflammation generated during Covid-19 infection and the direct infusion of inflammatory cytokines.
Upcoming results
According to Lira, the researchers are now evaluating other results obtained in the analyses, which should be published soon. The project is multicentric and has the participation of scientists from the University of Coimbra and the Polytechnic Institute of Coimbra (both from Portugal).
In addition, the same patients continue to be followed up after being vaccinated. There has already been an evaluation six weeks after the vaccine and the next one will be at the 18th month post-immunization.
Revista Galileu