Department of Cardiovascular Medicine, Mayo Clinic , Rochester, Minnesota.
J Appl Physiol (1985). 2018 Jul 1;125(1):190-197. doi: 10.1152/japplphysiol.01105.2017. Epub 2018 Apr 19.
It is unknown whether the greater total work of breathing (WOB) with aging is due to greater elastic and/or resistive WOB. We hypothesized that older compared with younger adults would exhibit a greater total WOB at matched ventilations (V̇e) during graded exercise, secondary to greater inspiratory resistive and elastic as well as expiratory resistive WOB. Older (OA: 60 ± 8 yr; n = 9) and younger (YA: 38 ± 7 yr; n = 9) adults performed an incremental cycling test to volitional fatigue. Esophageal pressure, inspiratory (IRV) and expiratory reserve volumes (ERV), expiratory flow limitation (EFL), and ventilatory variables were measured at matched V̇e (i.e., 25, 50, and 75 l/min) during exercise. The inspiratory resistive and elastic as well as expiratory resistive WOB were quantified using the Otis method. At V̇e of 75 l/min, older adults had greater %EFL and larger tidal volumes to inspiratory capacity but smaller relative IRV ( P ≤ 0.03) than younger adults. Older compared with younger adults had greater total WOB at V̇ of 50 and 75 l/min (OA: 90 ± 43 vs. YA: 49 ± 21 J/min; P < 0.04 for both). At V̇e of 75 l/min, older adults had greater inspiratory elastic and resistive WOB (OA: 44 ± 27 vs. YA: 24 ± 22 and OA: 23 ± 15 vs. YA: 11 ± 3 J/min, respectively, P < 0.03 for both) and expiratory resistive WOB (OA: 23 ± 19 vs. YA: 14 ± 9 J/min, P = 0.02) than younger adults. These data demonstrate that aging-induced pulmonary alterations result in greater inspiratory elastic and resistive as well as expiratory resistive WOB, which may have implications for the integrated response during exercise. NEW & NOTEWORTHY Aging-induced changes to the pulmonary system result in increased work of breathing (WOB) during exercise. However, it is not known whether this higher WOB with aging is due to differences in elastic and/or resistive WOB. Herein, we demonstrate that older adults exhibited greater inspiratory elastic and resistive as well as expiratory resistive WOB during exercise.
目前尚不清楚随着年龄的增长，呼吸总功（WOB）的增加是由于弹性和/或阻力 WOB 的增加。我们假设与年轻人相比，老年人在分级运动期间以匹配的通气量（V̇e）进行运动时，总 WOB 会更大，这是由于吸气阻力和弹性以及呼气阻力 WOB 更大所致。老年（OA：60±8 岁；n=9）和年轻（YA：38±7 岁；n=9）成年人进行递增式踏车测试直至疲劳。在运动期间，以匹配的 V̇e（即 25、50 和 75 l/min）测量食管压力、吸气（IRV）和呼气储备容积（ERV）、呼气流量受限（EFL）和通气变量。使用 Otis 方法量化吸气阻力和弹性以及呼气阻力 WOB。在 V̇e 为 75 l/min 时，与年轻人相比，老年人的 EFL%和潮气量与吸气量之比更大，但相对 IRV 更小（P≤0.03）。与年轻人相比，老年人在 50 和 75 l/min 的总 WOB 更大（OA：90±43 与 YA：49±21 J/min；P<0.04）。在 V̇e 为 75 l/min 时，老年人的吸气弹性和阻力 WOB 更大（OA：44±27 与 YA：24±22 和 OA：23±15 与 YA：11±3 J/min，均 P<0.03）和呼气阻力 WOB（OA：23±19 与 YA：14±9 J/min，P=0.02）高于年轻人。这些数据表明，衰老引起的肺改变导致吸气弹性和阻力以及呼气阻力 WOB 增加，这可能对运动期间的综合反应产生影响。 新内容和值得注意的内容：衰老引起的肺系统变化导致运动时呼吸功（WOB）增加。然而，目前尚不清楚这种与衰老相关的更高 WOB 是否是由于弹性和/或阻力 WOB 的差异所致。在此，我们证明老年人在运动期间表现出更大的吸气弹性和阻力以及呼气阻力 WOB。
