The agency was able to examine one particular Chicago-area gym in August 2020 and discovered that out of eighty-one attendees of an indoor high-intensity exercise class, fifty-five of them, or 68 percent, eventually fell ill with the virus.
Twenty-two of those infected attended classes on or after the day coronavirus symptoms started, and roughly three-quarters of attendees wore face masks infrequently, the report added.
The gym’s guests were required to wear a mask only upon entry, had their temperatures taken, and were screened for any coronavirus-related symptoms. Workout equipment was also stationed at least six feet apart and class sizes were kept to a minimum.
The agency noted that it attributes the outbreak to “the high proportion of attendees with COVID-19 who participated in class while symptomatic, or asymptomatic and infectious.”
In another case in Hawaii, the CDC was able to link twenty-one COVID-19 cases to a fitness instructor who taught group classes at two facilities in Honolulu. According to the report, the fitness instructor was known to occasionally wear a mask when he was running his classes.
“Doors and windows were closed, and three large floor fans were directed toward the participants for cooling. (The instructor) was on a pedestal facing participants, shouting instructions and encouragement,” the CDC said.
The agency eventually concluded that the new infections were likely accelerated by the participants’ lack of masks, poor room ventilation, and possible aerosol emission from the instructor’s shouting.
“Aerosol emission during speech has been correlated with loudness, and COVID-19 outbreaks related to intense physical activity and singing have been previously reported,” the report said.
“To reduce SARS-CoV-2 transmission in fitness facilities, staff members and patrons should wear a mask, and facilities should enforce consistent and correct mask use (including during high-intensity activities) and physical distancing.”
The CDC has previously advised gym patrons to physically distance from others, frequently wash their hands, and always wear a mask.
“If the intensity of the exercise makes it difficult to wear a mask, it is especially important to do (that activity) outdoors away from others,” the agency’s website states.
“Remove your mask if it gets moist from sweat and replace it with a clean mask while exercising. Have more than one mask on hand so that you can easily replace a moist mask with a dry one.”
Ethen Kim Lieser is a Minneapolis-based Science and Tech Editor who has held posts at Google, The Korea Herald, Lincoln Journal Star, AsianWeek, and Arirang TV. Follow or contact him on LinkedIn.