CDC urges masks, better ventilation in gyms

Gym users should wear masks when exercising, even if they are more than 6 feet apart, and the facilities need to improve ventilation, the Centers for Disease Control and Prevention recommended.

The CDC cited multiple outbreaks at gyms in Chicago and Honolulu tied to inadequate mask wearing, lack of physical distancing and poor ventilation, even when the facilities were open with limited capacity.

The findings in both cases highlight the risk of working out indoors with other people, and emphasize the need for gyms to follow rigorous COVID-19 prevention protocols.

In Chicago, 55 of the 81 people who attended high-intensity classes at a gym between Aug. 24 and Sept. 1 tested positive for COVID-19.  

The classes were held at 25 percent capacity, and people brought their own weights and mats. Mask use, temperature checks and symptom screenings were required on entry, but patrons were allowed to remove masks during exercise.

Among the people who tested positive, 22 of them attended multiple classes on or after exhibiting symptoms, and three attended even after having tested positive for the virus. A majority of patrons did not wear masks.

After receiving notification of a COVID-19 case in one of its patrons, the gym closed and informed all attendees of possible COVID-19 exposure, according to the CDC. It reopened 13 days later, and only those who had proof of a negative coronavirus test were allowed to return.

In Honolulu, 21 COVID-19 cases across three gyms were linked to a single case in a 37-year-old fitness instructor. Before his symptoms began, the instructor taught classes at two fitness facilities. The outbreak at a third was tied to another student, who also taught classes.

According to the CDC, mask wearing was inconsistent at best across multiple yoga classes and high intensity indoor cycling sessions.

The rate of transmission was highest on the day of symptom onset for both instructors, and transmission was likely facilitated by not wearing face masks, extended close contact and poor room ventilation.

At the cycling sessions, transmission was likely aided by shouting. The instructor said he was on a pedestal facing participants, shouting instructions and encouragement from more than 6 feet away. 

Neither he nor the students wore masks, as they were not required. Doors and windows were closed, and three large floor fans were directed toward the participants for cooling.