air flow resistance appeared to be higher while wearing a mask, with the cloth mask causing significantly more air flow resistance than the two-ply surgical mask. as well, the perception of dyspnea (shortness of breath) was higher while wearing the cloth mask than when wearing the surgical mask or no mask, but the surgical mask was no different in dyspnea perception than with no mask at all. there were no significant differences in heart rate, blood oxygen saturation, and respiration (breathing depth and frequency) between no mask and the two masks.
face temperatures were greater, however, while wearing any face mask compared to no mask; cloth masks were hotter with or without a fan, and surgical masks were hotter than no mask but only when the fan was on. wearing a cloth mask increased swings of mouth pressure but so, too, would using a mouthpiece used in a standard cardiopulmonary exercise test, so the researchers did not find this significant.
compared to no mask, athletes breathed in less oxygen but more carbon dioxide while wearing any mask. they breathed out more oxygen but less carbon dioxide while wearing any mask.
what it all means
given the lack of differences for heart rate, blood oxygen saturation, and breathing patterns, the differences in air flow resistance appear unlikely to seriously affect athletic performance. the researchers concluded that any changes or perceived reductions in performance while wearing a face mask were because the athletes were not used to wearing any kind of face covering while exercising. such unfamiliarity can make people feel discomfort and, as a result, can reduce their athletic performance.