The prevalence and predictors of tidal expiratory flow limitation during peak exercise do not differ between genders in healthy adolescents and young adults.

Abstract

Introduction: Tidal expiratory flow limitation (EFL T ) occurs when the tidal breath reaches its maximal capacity to generate flow despite increased expiratory effort. It has been suggested there are gender differences; females tend to develop EFL T due to lower markers of ventilatory capacity, and the primary determinants of EFL T in males relate to higher oxygen demand. Aim/hypothesis: This study aimed to determine the prevalence and predictors of EFL T during peak exercise in healthy subjects aged 10-24 years. We hypothesised that the prevalence and predictors of EFL T would not differ between males and females. Method: Healthy, physically active subjects (n=122, 69M:53F) with normal spirometry and gas exchange completed a maximal cardiopulmonary exercise test. The presence and degree of EFL T during peak exercise was determined by the vector-based analysis technique described by Welch et al (2021). Student’s T-test compared continuous variables and predictors of EFL T were determined by two-way ANOVA for sex and the presence of EFL T . Results: EFL T was present in 70% of subjects, with no difference in the prevalence between males and females (74 vs. 66%). The degree of EFL T was significantly greater in the males compared to females (40 vs. 30% of tidal volume, p<0.05). Subjects demonstrating EFL T had relatively lower forced expired volume in the first second (FEV 1 ), FEV 1 /forced vital capacity ratio, and mid expiratory flows. During peak exercise, male and female subjects demonstrating EFL T had higher relative peak oxygen consumption, ventilatory equivalents, breathing frequency, and minute ventilation relative to body weight. Conclusion: This study showed no gender difference in the prevalence of EFL T in healthy, physically active subjects. For both genders, lower markers of ventilatory capacity and higher markers of oxygen demand were predictors of EFL T . This research was supported by an award from The Green Lane Research and Education Fund Board. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.