Effect of Nasal Versus Oral Breathing on Vo2max and Physiological Economy in Recreational Runners Following an Extended Period Spent Using Nasally Restricted Breathing

Background: In subjects who do not practice nasally restricted breathing, peak oxygen uptake (VO2max) and time to exhaustion in a graded exercise protocol (GXT TE) are impaired while breathing nasally versus orally. Objective: This study investigated the effect of oral versus nasal breathing on VO2max, GXT TE and physiological economy (PE) in subjects who had previously self-selected a nasal only breathing approach during training and racing. Methods: A mixed gender sample (N=10, 5 male and 5 female) of nasal breathing recreational runner’s completed a maximal GXT and high level steady state trial at 85% of their maximal GXT running velocity (SS85) in both nasally and orally restricted breathing conditions. Results: In the GXT trials the subjects exhibited no significant mean difference in GXT TE, VO2max or peak lactate. However, in the nasally restricted breathing condition they demonstrated a significantly lower mean ventilatory equivalent for both oxygen (VE/VO2) (p = 0.002), and carbon dioxide (VE/VCO2) (p = 0.043) at VO2max with large effect sizes. During the SS85 trials the subjects exhibited a significantly better PE (P = 0.05) and no significant difference in lactate production, as well as a significantly lower mean VE/VO2 (p = 0.002) and VE/VCO2 (p = 0.002) with large effect sizes. Conclusion: This study supports the ability of recreational runners to utilize a nasally restricted breathing pattern at all levels of running intensity without loss in VO2max or GXT TE, and with superior PE and VE/VO2, following an extended training period using this practice