Long Covid may be associated with lack of physical activity, study suggests

The link between persistent Covid-19 symptoms and physical inactivity is becoming increasingly evident.

In study recently published in the journal Scientific Reports, researchers from the University of São Paulo (USP) point out that patients with at least one prolonged symptom of the coronavirus infection have a 57% greater risk of being sedentary. That number grows to 138% among those reporting five or more “post-acute SARS-CoV-2 sequelae,” as the researchers put it.

“Despite being a cross-sectional study, the results of this investigation highlight the importance of discussing and encouraging physical activity during the pandemic as well,” says Hamilton Roschel, one of the coordinators of the Research Group on Applied Physiology and Nutrition at USP.

The work is one of the first to assess the effect of physical activity in the context of long-term Covid, a condition usually characterized by the persistence of symptoms for at least two months – and which cannot be explained by problems other than infection with this virus. The study was supported by the State of São Paulo Research Foundation (FAPESP).

A 2020 report already pointed out that 76% of patients hospitalized because of the coronavirus reported at least one persistent symptom six months after discharge.

Cross-sectional study

The data analyzed were collected within the framework of the Covid-19 Study Group, which brings together patients admitted to the Hospital das Clínicas, in São Paulo. A total of 614 people, with an average age of 56 years, were included in the investigation, all with a diagnosis confirmed by laboratory tests.

From 6 to 11 months after hospitalizations (which occurred between October 2020 and April 2021), they were examined and answered several questionnaires, which covered the practice of physical activity, lifestyle and the possible presence of ten associated symptoms to Covid-19 – from shortness of breath to memory problems.

Inactivity was defined following the criteria of the World Health Organization (WHO). That is, less than 150 minutes of physical activity per week. “In our case, this involved commuting, sports, housework”, adds Roschel. The researchers then crossed data involving Covid-19 symptoms with physical inactivity to arrive at the results.

More symptoms, more sedentary lifestyle

Of the patients analyzed, 60% were physically inactive – a rate higher than the 47% observed in the Surveillance of Risk and Protective Factors for Chronic Diseases by Telephone Survey (VIGITEL) survey, carried out by the Ministry of Health in 2020, for Brazilians in the age group similar.

They also had a high rate of comorbidities: 37% were smokers, 58% had hypertension, 35% were diagnosed with diabetes, and 17% were obese.

“These are risk factors for worsening Covid-19. As all the people analyzed were hospitalized, it was natural that they appeared frequently”, argues Roschel. To get an idea, 55% needed care in the ICU [Unidade de Terapia Intensiva] and 37% on mechanical ventilation.

Even making adjustments to prevent these and some other factors from interfering with the results, the presence of at least one persistent symptom was associated with a 57% higher risk of sedentary lifestyle, as mentioned before. “And, the more symptoms, the greater the percentage of physical inactivity”, adds Roschel. The presence of five or more symptoms increased the risk of physical inactivity by 138%.

He also points out that certain post-acute consequences of Covid-19 were especially linked to the lack of movement. In the adjusted statistical models, the ones that called the most attention were shortness of breath (132% greater risk of being inactive) and fatigue (101%).

“It makes sense to imagine that individuals with these conditions would find it more difficult to maintain an active routine”, says Roschel. “But it is also plausible to imagine that inactive participants are more subject to these prolonged symptoms after infection. Our study does not allow us to infer causality, ”she ponders.

Associations and hypotheses

In the article, the authors write that physical inactivity “may itself be considered as a persistent symptom among COVID-19 survivors.” The hypothesis is echoed in other works. A Dutch survey – also mentioned in the Brazilian study in question – with 239 patients revealed a significant reduction in the time devoted to walking six months after the onset of the first symptoms.

Roschel also conjectures, based on other studies, that a sedentary lifestyle could, in theory, increase the risk of long-term Covid. A 2021 investigation signed by him, incidentally, concludes that people with better muscle health (from there, it can be speculated that they would be less sedentary) hospitalized because of SARS-CoV-2 tend to spend less time hospitalized.

Additionally, in a subsequent study, the same researchers observed that those who lost more muscle mass during the hospitalization period were also those who had higher health costs and more persistent symptoms six months after discharge.

An American survey examined the previous physical activity history of 48,440 individuals subsequently infected with the coronavirus. Result: those consistently active had lower risks of hospitalization, ICU admission, and death.

“Our work aggregates information by linking physical inactivity specifically with persistent symptoms of Covid-19. Future studies should investigate this association and understand the reasons behind it”, observes Roschel. It should be noted that this connection can occur in both ways. That is, both sedentary lifestyle would favor long Covid, and this would encourage inactivity.

“And, from a practical point of view, the need to value physical activity during the pandemic is clear”, reiterates Roschel. There are situations where patients who have already been infected must take certain additional precautions with the exercises – a doctor is able to analyze each case. However, physical activity needs to be encouraged as a public health measure, according to Roschel. A sedentary lifestyle is responsible for 9% of deaths from all causes in the world.