Abstract：
Given that there are both sex-based structural differences in the respiratory system and age-associated declines in pulmonary function, the purpose of this study was to assess the effects of age and sex on the metabolic cost of breathing (V̇o2RM) for exercise ventilations in healthy younger and older males and females. Forty healthy participants (10 young males 24 ± 3 yr; 10 young females 24 ± 3 yr; 10 older males 63 ± 3 yr, 10 older females 63 ± 6 yr) mimicked their exercise breathing patterns (voluntary hyperpnea) in the absence of exercise across a range of exercise intensities. At peak exercise, V̇o2RM represented a significantly greater fraction of peak oxygen consumption (V̇o2peak) in young females, 12.7 ± 4.0%, compared with young males, 10.7 ± 3.0% (P = 0.027), whereas V̇o2RM represented 13.5 ± 2.3% of V̇o2peak in older females and 13.2 ± 3.3% in older males. At relative ventilations, there was a main effect of age, with older males consuming a significantly greater fraction of V̇o2RM (6.6 ± 1.9%) than the younger males (4.4 ± 1.3%; P = 0.012), and older females consuming a significantly greater fraction of V̇o2RM (6.9 ± 2.5%) than the younger females (5.1 ± 1.4%; P = 0.004) at 65% V̇emax. Furthermore, both younger and older males had significantly better respiratory muscle efficiency than their female counterparts at peak exercise (P = 0.011; P = 0.015). Similarly, younger participants were significantly more efficient than older participants (6.5 ± 1.5% vs. 5.5 ± 2.0%; P = 0.001). Normal age-related changes in respiratory function, in addition to sex-based differences in airway anatomy, appear to influence the ventilatory responses and the cost incurred to breathe during exercise.NEW & NOTEWORTHY Here we show that at moderate and high-intensity exercise, older individuals incur a higher cost to breathe than their younger counterparts. However, as individuals age, the sex difference in the cost of breathing narrows. Collectively, our findings suggest that the normative age-related changes in respiratory structure and function, and sex differences in airway anatomy, appear to influence the ventilatory responses to exercise and the oxygen cost to breathe.
摘要：
鉴于呼吸系统存在基于性别的结构差异和与年龄相关的肺功能下降，这项研究的目的是评估年龄和性别对健康的年轻人和老年人运动通气的呼吸代谢成本（VO2RM）的影响，男性和女性。
方法：40名健康参与者（10名年轻男性23±3岁；10名年轻女性23±3岁；10名年长男性63±3岁，10名年龄较大的女性63±6yrs）在一系列运动强度中没有运动的情况下模仿了他们的运动呼吸模式。
结果：在运动高峰期，VO2RM代表了年轻女性峰值耗氧量（VO2peak）的显着较大比例，12.8±3.9%，与年轻男性相比，10.7±3.0%(P=0.027)，而VO2RM在老年女性中占VO2peak的13.5±2.3％，在老年男性中占13.2±3.3％。在相对通风时，年龄有一个主要的影响，老年男性的VO2RM（6.6％±1.9）明显高于年轻男性（4.4％±1.3；P=0.012），在最大65％时，老年女性消耗的VO2RM比例（6.9％±2.5）明显高于年轻女性（5.1％±1.4；P=0.004）。此外，在运动高峰期,年轻男性和老年男性的呼吸肌效率均显著优于女性男性(P=0.011;P=0.015).同样，年轻参与者的效率明显高于年长参与者(6.5%±1.5%vs.5.5±2.0%；P=0.001）。
结论：呼吸功能的年龄相关变化，和基于性别的气道解剖差异，影响运动期间的呼吸成本。在高峰运动期间，较高比例的VO2RM可能会使年轻女性和老年个体倾向于将更多的血流转移到呼吸肌，而以其他肌肉为代价。
方法：40名健康参与者（10名年轻男性23±3岁；10名年轻女性23±3岁；10名年长男性63±3岁，10名年龄较大的女性63±6yrs）在一系列运动强度中没有运动的情况下模仿了他们的运动呼吸模式。
结果：在运动高峰期，VO2RM代表了年轻女性峰值耗氧量（VO2peak）的显着较大比例，12.8±3.9%，与年轻男性相比，10.7±3.0%(P=0.027)，而VO2RM在老年女性中占VO2peak的13.5±2.3％，在老年男性中占13.2±3.3％。在相对通风时，年龄有一个主要的影响，老年男性的VO2RM（6.6％±1.9）明显高于年轻男性（4.4％±1.3；P=0.012），在最大65％时，老年女性消耗的VO2RM比例（6.9％±2.5）明显高于年轻女性（5.1％±1.4；P=0.004）。此外，在运动高峰期,年轻男性和老年男性的呼吸肌效率均显著优于女性男性(P=0.011;P=0.015).同样，年轻参与者的效率明显高于年长参与者(6.5%±1.5%vs.5.5±2.0%；P=0.001）。
结论：呼吸功能的年龄相关变化，和基于性别的气道解剖差异，影响运动期间的呼吸成本。在高峰运动期间，较高比例的VO2RM可能会使年轻女性和老年个体倾向于将更多的血流转移到呼吸肌，而以其他肌肉为代价。
