- In one week in August, 55 people attending a gym in Chicago learned about COVID-19.
- Less than a quarter of gym goers wore masks during their workouts and almost no one was socially distant.
- The gym had precautions such as temperature tests, but some people still went to class with symptoms.
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Dozens of people have been infected with COVID-19 after attending classes at a gym in Chicago in August, according to the February 24 Morbidity and Mortality Report from the Centers for Disease Control and Prevention (CDC).
The epidemic is associated with several classes of high-intensity interval (HIIT) conducted indoors.
According to the CDC, 55 people were infected ̵
The report recommends that people do not rely solely on social distancing or symptom screening to prevent indoor outbreaks – wearing masks is still key.
Infected people attend a gymnastics class with symptoms such as cough and fever
The gym had followed the precautions, conducting the exercises with 25% capacity and checking the clients with checks of temperature and symptoms upon entering.
Still, 22 people who attended had symptoms the same day they went to the gym, including fever, cough, headache and loss of smell and taste.
Three people went to class with positive tests for COVID-19 that day or before. Although no one died as a result of the outbreak, two people later went to the emergency room for treatment and one person had to be hospitalized for more than a week.
Masks were required to enter, but not during training
Two people with symptoms said they attended five exercises a week and later tested positive for infection. They both said they often trained without masks.
Masks were needed to enter the gym, but they can be removed during the lesson.
Only about one in four people say they wear masks while training, and about one in 20 say they maintain social distance during class.
This case highlights the need for people to wear masks while in the gym or otherwise around other people, according to the report. It also emphasizes the importance of quarantining people if they have symptoms, as they may expose others to infection while waiting for their test results.
Heavy breathing can spread virus particles, so good ventilation is key to preventing outbreaks.
Previous research has found that high-intensity activities, such as dance fitness or HIIT lessons, can be particularly risky for the spread of COVID-19. This is because heavy breathing and a lot of movement can spew virus particles into a small exercise space.
Proper ventilation can help reduce these risks. It is not clear how well ventilated the gym was in this report, although the CDC found that it was not originally intended for exercise.
But previous cases have found that good ventilation can prevent fitness attendees from getting sick, even if someone is infected during a workout. In one case from November 2020, a fitness instructor (infected but without symptoms) exposed 50 athletes to COVID-19 and no one else got sick.
The keys are to open doors and windows and monitor air quality, according to Dr. Lincy Marr, a fitness enthusiast and expert on ventilation and viral transmission at Virginia Tech.
If this is not possible, it is best to make sure everyone is wearing a mask and keep people at a distance of 10 feet throughout the workout.
“The most important thing I can say is to avoid the crowds. If you can go when it’s not crowded, it’s much safer,” Marr told Insider earlier.