Masks do not need to be worn during "vigorous intensity physical activity," the WHO has said.
The WHO, or the World Health Organization, made updated guidelines, citing new research.
The research says wearing masks can have negative effects, reports Business Insider.
The WHO said other prevention measures, like distancing and ventilation, need to be in place.
This includes indoor exercise venues or these venues should temporarily close.
Some experts disagree with the guidance, however, citing that masks don't impair breathing.