The switching point from nasal to oronasal breathing

Respir Physiol. 1980 Oct;42(1):61-71. doi: 10.1016/0034-5687(80)90104-8.


The switching point from nasal to oronasal breathing during incrementally graded submaximal exercise was determined in 30 (14 M, 16 F) healthy adult volunteers. Nasal airflow was measured by a pneumotachograph attached to a nasal mask. Oral airflow was determined as the difference between nasal airflow and total pulmonary airflow, the latter being measured by a head-out exercise body plethysmograph. The airflow and pressure signals were sampled every 20 msec by a micropressor, which calculated respiratory volumes and nasal work of breathing, and produced an on-line print-out. Twenty of the 30 subjects (normal augmenters) switched from nasal to oronasal breathing at submaximal exercise of 105.0 W (SD = 30.1), four subjects (mouth breathers) breathed habitually oronasally, five subjects (nose breathers) persistently breathed through the nose only, and one subject showed no consistent nose/mouth breathing pattern. In normal augmenters, the onset of oronasal breathing (VE 35.3 +/- 10.81 . min-1) was quite consistent individually, but varied considerably between inividuals without showing a significant sex difference. The factors most closely related to the switching point were rating of perceived exertion of breathing and nasal work of breathing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Female
  • Humans
  • Male
  • Mouth Breathing / physiopathology*
  • Nasal Cavity / physiopathology*
  • Physical Exertion*
  • Respiration*
  • Time Factors
  • Work of Breathing