RELATION BETWEEN HABITUAL AND OBLIGATORY ORONASAL SWITCHING POINT WITH TIDAL VOLUME AND RESPIRATION RATE DURING EXERCISE.

Oral breathing during exercise is effective in appearance of exercise-induced asthma. The aim of this study was to determine the relation between habitual and obligatory oral nasal switching points with tidal volume and respiration rate during exercise in non-athlete, and non-smoker adults.

Materials & Methods: For this assessment twenty volunteers (ten males and ten females) were selected. After tidal volume and respiration frequency measurement, two protocols were done using body plethysmograph. In these protocols, habitual and obligatory oronasal switching point was determined during exercise on ergometer bicycle. Also ventilation rate and work load were measured in switching times.

Results: The results indicate that habitual oral-nasal switching points were shorter than the obligatory oral nasal switching points and both switching times were shorter in females. The significant correlation was determined between tidal volume and obligatory oral nasal switching points in males.

Conclusion: Our findings suggest that increase of ventilation rate is one of effective determinants of obligatory oral nasal switching points and effect of increase of tidal volume especially in females is more important for this determination. H owever, the ventilation rate is more in males than females, but slope of Alveolar ventilation / oral nasal switching points curve is steeper in females. In conclusion, ventilatory impulses drive from respiratory center is more accelerated in females in regard to men.