Supplementary Material for: Exercise Physiology at “Conversational Level” Is Not Impaired in Healthy Young Subjects Wearing Masks or Respirators

Objective: The aim of this study was to evaluate the effects of the use of both surgical masks and FFP2 respirators on the inspiratory muscle strength, metabolic parameters, heart rate, subjective perceived exertion, and dyspnea perception, before and during 30 min stable load exercise at “conversational level”. Methods: A randomized cross-over study was carried out. Nineteen healthy adults completed 3 conditions (without a mask, with a surgical mask or an FFP2 respirator) during a 30-min steady-state test at the lactate threshold intensity. Inspiratory muscle strength was measured before and after the test, and metabolic parameters, heart rate, subjective perceived exertion, and dyspnea perception were collected at baseline, during, and after the test. Results: There was a significant reduction in inspiratory muscle strength after the 30-min test in all conditions (control: 6.26 mm Hg, p < 0.5; surgical mask: 8.55 mm Hg, p < 0.01; FFP2 respirator: 12.42 mm Hg, p < 0.001), but without significant differences between them (p = 0.283). Data showed a statistically significant effect for time, but did not show a statistically significant interaction between condition and time for heart rate (p = 0.674), oxygen saturation (p = 0.297), blood lactate level (p = 0.991), rating perceived exertion (p = 0.734) and dyspnea (p = 0.532) comparisons. Conclusions: The present study findings suggested that inspiratory muscle strength and physiological parameters during “conversational level” exercise were not impaired under wearing masks in healthy, nonsmoking young adults.