Health authorities urged people to wear face masks when visiting gyms after reports found public exercise centres were the source of Covid-19 outbreaks. Two studies, published by the US Centres for Disease and Prevention, showed that going maskless when working out put people at higher risk of contracting the disease. In two separate cases, significant outbreaks during the summer were linked to gyms in Chicago and Honolulu. In the Chicago report, 68 per cent of gym-goers, who attended in-person fitness classes at one gym between August 24 and September 1, tested positive for Covid-19. “Covid-19 cases were identified among 55 of 81 attendees of in-person classes,” the report said. “Twenty-two attendees with Covid-19 participated in classes on or after the day symptoms started. “Among 58 exercise class attendees who provided information on in-class behaviours, 44 reported infrequent mask use. "Overall, 43 attendees with Covid-19 participated in multiple classes while potentially infectious." The outbreak occurred even though capacity for exercise classes was capped at 25 per cent, with only 10 to 15 people present in each class. The findings proved that carelessness about masks and symptoms could lead to more outbreaks. Researchers said heavy breathing during intense physical activity in small spaces increased the chances of transmission. They suggested that gym-goers either wear masks correctly at all times, or move workouts outdoors or online. In another case, all 10 people who attended a spinning class at a gym in Honolulu contracted the virus. Health officials linked the outbreak to a male fitness instructor who led the class just hours before the onset of his first symptoms. One of the participants who became infected was a 46-year-old fitness instructor from another gym who was later admitted to a hospital's intensive care unit. “This outbreak reinforces the need for combined Covid-19 prevention strategies, including universal mask use in public settings … especially indoors,” the report said. “In addition, the potential for infected persons to infect others between their testing date and receipt of test result reinforces the need to quarantine while waiting for a Covid-19 test result and avoid gatherings while unknowingly infectious.” This month, the UAE introduced a series of new restrictions designed to slow the spread of Covid-19. In Abu Dhabi, capacity at gyms was limited to 50 per cent and in Dubai many exercise centres across the city cut class sizes and installed plastic dividers between equipment. As part of ongoing inspections by the Department of Economic Development in Dubai, several gyms have been shut for breaching Covid-19 safety rules. As it stands in the UAE, people taking part in heavy exercise do not have to wear a mask. However, as in the latest CDC reports, it is recommended that people wear nose and mouth coverings at all times to limit the spread of infection when working out indoors.