Acute ventilatory and hemodynamic responses to nasal versus oral breathing during normoxia, hypoxia, and hypercapnia

This is the authors' abstract. We don't add key points for this paper.

This study is the first to compare nasal, oral, and free breathing during normoxia, hypoxia, and hypercapnia. Although breathing mode had negligible effects at rest in normoxia, nasal breathing was associated with changes in cardiorespiratory responses to chemoreflex stress: it attenuated the hypoxic rise in heart rate. Moreover, during hypercapnia, nasal breathing was associated with a lower [Formula: see text]. Conversely, oral breathing was associated with a lower cardiovagal baroreflex sensitivity. Overall, these findings suggest that nasal breathing may represent a simple strategy to support cardiorespiratory function under chemoreflex stress.