Introduction The advent of the Coronavirus 19 (COVID-19) pandemic, which has quickly spread worldwide, has raised the attention regarding the use of respiratory protective face masks (PFM) not only by healthcare personnel, but also the general population. In this context, wearing a PFM during physical exercise in an external environment can reduce COVID-19 infection risks. On the other hand, the use of PFM can increase the subjective perception of breathing difficulty through the formation of microclimates inside the face mask […]