The Centers for Disease Control and Prevention are calling for stricter precautions for gym goers after tracking outbreaks of coronavirus in fitness centers in Hawaii and Chicago that have left dozens of customers with COVID-19.
The results, detailed in two articles published this week in the CDC’s Weekly Morbidity and Mortality Report, highlight the risks of physical fitness activities in closed environments, especially when the guidelines on wearing a mask and social distance are not met.
But even when used correctly, masks may not do enough to mitigate the risk of indoor group classes, said Dr. Larry William Chang, an infectious disease specialist at Johns Hopkins University School of Medicine, who was not involved in the search.
“I personally would never participate in a group class in an enclosed space with little ventilation,” said Chang. “I think it’s just a recipe for disaster.”
The first of the two outbreak cases occurred in Hawaii and began in late June, after two fitness instructors – one apparently infected by the other – transmitted the virus to clients before developing any symptoms of COVID-19.
A total of 20 of the 21 people who were exposed to any of the instructors in the 24-hour period before showing signs of illness ended up becoming infected after attending a class or personal training session. Another eight customers were exposed in the previous 24 hours, and one of them also contracted the coronavirus.
Of these 21 infections attributed to the instructors, 20 patients (including the second instructor) developed COVID-19 and two of them were hospitalized.
At the time of the outbreak, wearing a mask was not mandatory in fitness facilities, the authors wrote.
Some of the classes seemed designed to spread the virus. For example, there was a high-intensity cycling class in which the infected instructor faced a group of 10 participants without a mask and shouted instructions to them. Three large floor fans blew air towards customers for cooling; doors and windows remained closed.
“They basically created an ideal environment for the transmission of the coronavirus,” said Chang. “I mean, you had closed spaces, inadequate ventilation, masks were often not used or needed, and people did vigorous exercises. This is essentially a recipe for a super-propagating event. “
The Chicago outbreak occurred about two months later. There, the use of a mask, temperature checks and symptom tests were necessary at the entrance. Customers brought their own rugs and weights and were positioned at stations at least two meters apart. However, they were allowed to remove their masks while exercising.
“I think in Chicago they did some things that we sometimes call public health theater,” said Chang. Asking if people show symptoms does not catch people who are asymptomatic transmitters or who do not speak the truth. Temperature checks are insufficient because not all people who are contagious will have a fever. “None of this is likely to have a major effect in reducing the risk of coronavirus transmission in your facility,” he said.
In fact, 55 of 81 people who attended high-intensity indoor classes at the Chicago gym sometime between August 24 and September 1 were infected and developed COVID-19.
In addition, 43 participants with COVID-19 attended several classes while they were potentially infectious. And 22 participants with COVID-19 attended these classes on – or after – the day they started experiencing symptoms.
Class participants were interviewed about their behavior at the gym. Of the 38 participants who had COVID-19, 32 (84%) reported infrequent use of a mask. (The same was true of 12 out of 20 – 60% – people who did not become ill.) Three of the people with COVID-19 attended the gym on the same day – or after – of receiving a positive coronavirus test.
In the end, two of the 55 people visited an emergency room and one was hospitalized for eight days.
Both research teams suggested ways to reduce the risk of working out at a gym, such as significantly improving ventilation, imposing consistent and correct use of the mask and physical distance, reminding all customers and employees to stay home if they are sick and increase hygiene opportunities.
“Performing physical activities entirely outdoors or virtually can further reduce the risk of SARS-CoV-2 transmission,” added both research teams.
Chang said the safest place to exercise would probably be at home or outdoors. But not everyone is able to do that, and that’s where gyms come in.
“Gyms are a social and public health asset,” he said. “It is important for people to exercise and some people are unable to exercise at home or outdoors. So I think that many gyms can remain open – but they really need to have some vigorous policies and adjustments in place.