It’s safe to go back to the gym if there’s little COVID-19 around, study suggests | Science

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Wondering if it's safe to go back to the gym? Norwegian athletes may have good news for you. A study on the risk of coronavirus transmission in Oslo found that people who went to the gym were not more likely to become infected or sick than people who did not. Norway has reopened its gyms based on provisional results, which were released yesterday as a prepress and are yet to go through a peer review.

But some epidemiologists are not so sure. It is possible that no one was infected in those Oslo gyms because there were very few cases of COVID-19 in the city when the study was conducted, not because working on the treadmill or lifting weights in the midst of a pandemic is safe.

So far, crucial decisions to reopen public spaces after closings are made on the basis of little evidence. All the children who return to school and all the Zumba fans who return to class participate in a large and uncontrolled experiment. A much better approach is to carefully study the impact of each new step on reopening, argues Mette Kalager, a clinical epidemiologist at the University of Oslo and one of the study's leading scientists.

Kalager and his colleagues worked with gyms in Oslo to recruit about 4,000 participants, none of whom had been tested for COVID-19, in May and June. At the time, Norway had reported 8,309 confirmed cases and 235 COVID-19-related deaths since February, with the peak of the outbreak nationwide in early May.

Although the gyms in Norway were still closed, half of the participants had the opportunity to train in five gyms that were specifically opened for the study and maintained rigid standards of hygiene and social distancing, such as cleaning machines after each use and maintaining visitors 2 meters apart. The only people the athletes encountered were other study participants and gym staff. More than 80% of people in this group came to the gym at least once in the 2-week study period, and almost 40% went more than six times. The other half were not allowed to visit the gym, and went on with their daily lives as usual. After approximately 2 weeks, both groups evaluated themselves for SARS-CoV-2 using polymerase chain reaction swab tests.

Almost 80% of the participants submitted their tests. None of the 1,868 people in the control group tested positive, and only one of the 1,896 people who did gymnastics did, but that person had not yet gone to the gym and was probably infected elsewhere, the researchers reported in a published preprint. in medRxiv. Kalager and colleagues also searched Norway's comprehensive public medical records and found that none of the participants in either group had been admitted to a hospital with COVID-19 related complaints.

That doesn't mean gyms are safe, says Darren Dahly, an epidemiologist at University College Cork. During the study weeks, Oslo reported only a few new cases per day, with a maximum of 24 in 1 day. That means the people in the study were already at a very low risk, he says, possibly too low for a significant difference to be detected between the two groups.

Emily Smith, an epidemiologist at George Washington University, agrees. "There were zero sick people who went to the gym in this study," she says. "We need to know what happens when people who are sick with COVID, but perhaps still have no symptoms or mild symptoms, go to the gym, take a spin class, and share a locker room with others." Smith also notes the short period of time covered by the study: People who started going to the gym a little later in the study period may have been exposed, but they might have been tested too early in the incubation period for the virus. be detectable.

Kalager agrees that the results can't determine whether it's safe to hit the gym in places like Arizona "where the incidence of COVID-19 is much higher." But in places with a low number of new cases, "it's safe," she says.

Widespread publicity about the results without noticing the warnings could be harmful, says Hilda Bastian, a former consumer health advocate and Ph.D. Bond University student studying evidence-based medicine. "The risk is that people think it means that all gyms are safe, if there are only a few hygiene measures and a little social distancing," she says.

But Bastian applauds the use of a clinical trial to study the safety of the reopening. "Using essays to answer these kinds of questions is a good thing," agrees Dahly. Each reopening is an experiment, he says. The question is "whether or not you are going to learn from that."

The next test that Kalager and his colleagues plan to conduct will compare the risk of infection in newly reopened gyms in Oslo that have more or less strict hygiene and social distancing measures. With a much larger number of attendees, he says, the trial may offer stronger evidence on gym safety and the success of hygiene measures.