Effects of oral, oronasal, and oronasal breathing with a decongested nose during incremental maximal exercise testing of well-trained endurance athletes: a randomized cross-over study.

Introduction: Nasal breathing is preferable for persons at rest and remains partially active during oronasal breathing in exercise. However, its potential contribution to performance-particularly in cases with a decongested nose-remains understudied in well-trained athletes. This study investigates whether nasal airflow during oronasal breathing influences performance in well-trained, endurance athletes. Specifically, we examine whether nasal decongestion during oronasal breathing enhances ventilatory efficiency and, thereby, improves time-to-exhaustion (TTE), maximal oxygen uptake ( Methods: Twelve male, well-trained cyclists/triathlon athletes (mean Results: There were no significant differences between the three breathing modes (p > 0.05) in terms of the cardiopulmonary or performance parameters, including the rate of perceived exertion, respiratory frequency, mean minute ventilation, Conclusion: Oral-only breathing is associated with a non-significant shorter TTE than oronasal breathing with or without nasal decongestion, although it results in significantly lower mean capillary blood lactate levels following maximal aerobic exercise. These findings suggest that a single, low-resistance oral breathing route reduces lactate accumulation under maximal effort, whereas oronasal breathing-particularly in the presence of nasal decongestion-may be more beneficial for sustaining endurance.