School of Kinesiology, University of British Columbia , Vancouver , Canada.
Centre for Heart and Lung Innovation, St. Paul's Hospital , Vancouver , Canada.
J Appl Physiol (1985). 2018 Apr 1;124(4):1092-1106. doi: 10.1152/japplphysiol.00608.2017. Epub 2017 Dec 14.
We examined the effects of age, sex, and their interaction on mechanical ventilatory constraint and dyspnea during exercise in 22 older (age = 68 ± 1 yr; n = 12 women) and 22 younger (age = 25 ± 1 y, n = 11 women) subjects. During submaximal exercise, older subjects had higher end-inspiratory (EILV) and end-expiratory (EELV) lung volumes than younger subjects (both P < 0.05). During maximal exercise, older subjects had similar EILV ( P > 0.05) but higher EELV than younger subjects ( P < 0.05). No sex differences in EILV or EELV were observed. We noted that women had a higher work of breathing (W) for a given minute ventilation (V̇e) ≥65 l/min than men ( P < 0.05) and older subjects had a higher W for a given V̇e ≥60 l/min ( P < 0.05). No sex or age differences in W were present at any submaximal relative V̇e. At absolute exercise intensities, older women experienced expiratory flow limitation (EFL) more frequently than older men ( P < 0.05), and older subjects were more likely to experience EFL than younger subjects ( P < 0.05). At relative exercise intensities, women and older individuals experienced EFL more frequently than men and younger individuals, respectively (both P < 0.05). There were significant effects of age, sex, and their interaction on dyspnea intensity during exercise at absolute, but not relative, intensities (all P < 0.05). Across subjects, dyspnea at 80 W was significantly correlated with indexes of mechanical ventilatory constraint (all P < 0.05). Collectively, our findings suggest age and sex have significant impacts on W, operating lung volumes, EFL, and dyspnea during exercise. Moreover, it appears that mechanical ventilatory constraint may partially explain sex differences in exertional dyspnea in older individuals. NEW & NOTEWORTHY We found that age and sex have a significant effect on mechanical ventilatory constraint and the perception of dyspnea during exercise. We also observed that the perception of exertional dyspnea is associated with indexes of mechanical ventilatory constraint. Collectively, our results suggest that the combined influences of age and biological sex on mechanical ventilatory constraint during exercise contributes, in part, to the increased perception of dyspnea during exercise in older women.
我们研究了年龄、性别及其相互作用对 22 名老年（年龄=68±1 岁；n=12 名女性）和 22 名年轻（年龄=25±1 岁，n=11 名女性）受试者在运动时机械通气受限和呼吸困难的影响。在亚最大运动时，老年受试者的吸气末（EILV）和呼气末（EELV）肺容积高于年轻受试者（均 P<0.05）。在最大运动时，老年受试者的 EILV 相似（P>0.05），但 EELV 高于年轻受试者（P<0.05）。在 EILV 或 EELV 方面，男女之间没有差异。我们注意到，女性在给定分钟通气量（V̇e）≥65 l/min 时的呼吸功（W）高于男性（P<0.05），而老年受试者在给定 V̇e≥60 l/min 时的 W 更高（P<0.05）。在任何亚最大相对 V̇e 下，男女之间均无 W 差异。在绝对运动强度下，老年女性比老年男性更频繁地经历呼气流量受限（EFL）（P<0.05），而老年受试者比年轻受试者更有可能经历 EFL（P<0.05）。在相对运动强度下，女性和老年个体比男性和年轻个体更频繁地经历 EFL（均 P<0.05）。在绝对强度下，年龄、性别及其相互作用对运动时呼吸困难的强度有显著影响，但在相对强度下没有影响（均 P<0.05）。在所有受试者中，80 W 时的呼吸困难与机械通气受限的指标显著相关（均 P<0.05）。综上所述，我们的研究结果表明，年龄和性别对运动时的 W、工作肺容积、EFL 和呼吸困难有显著影响。此外，机械通气受限似乎部分解释了老年女性运动性呼吸困难的性别差异。
