Assessment of Habitual and Obligatory Nasal to Oronasal Breathing Switching Time in Healthy and Non Smoker Non-Athlete Adults

Numerous studies have been performed on habitual nasal to oronasal breathing switching in exercise. However no investigation has reported quantative comparison between habitual and obligatory nasal to oronasal breathing time in exercise. Twenty healthy non-athlete non-smoker subjects (10 males and 10 females) age 20±2 years were randomly selected and then were exercised in two protocols. In first protocol, they were exercised on ergometer in incremental method of exercise (incrementally graded exercise) until opening of mouth (habitual OSP) occurred, and in second protocol, this incremental exercise on ergometer were done with closed mouth until involuntary opening of mouth occurred (obligatory OSP) and ventilation rate were simultaneously measured in two protocols. The habitual and obligatory OSP were 152.68 ± 11.85 and 464.7 ± 12.88 seconds in males and 157.75 ± 19.64 and 271.43 ± 12 seconds in females, respectively. A significant correlation was showed between habitual OSP and workload, and between obligatory OSP, workload and ventilation differences.: Our data showed that obligatory OSP was longer than habitual OSP in males and habitual OSP is shorter than obligatory OSP in two genders. Also increase of ventilation slope was faster in females than in males.