Department of Pulmonary Diseases, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Med Sci Sports Exerc. 2011 Jun;43(6):996-1001. doi: 10.1249/MSS.0b013e318205e2be.
Patients with chronic obstructive pulmonary disease (COPD) report more dyspnea during arm than during leg exercise. One of the major causes of dyspnea is dynamic hyperinflation (DH), which is caused by airflow limitation as well as increase in ventilation. The aims of our study were to compare DH at equal ventilation (isoventilation) during arm and legwork and to investigate the effects of breathing pattern on DH.
Thirteen clinically stable patients with mild to very severe COPD (forced expiratory volume in 1 s = 59% ± 21%) participated in this study. Arm and leg constant work rate (CWR) ergometry were performed in random order with ventilation equal to that at 50% of peak armload. The corresponding leg load of that level of ventilation was determined from the incremental leg test. Respiratory physiology was measured breath-by-breath. Change in inspiratory capacity, measured at rest and at 2-min intervals, was used to reflect DH.
At steady-state isoventilation (37 ± 2 and 36 ± 2 L · min for arm and leg CWR tests, respectively, P > 0.05), armload was 29 ± 5 W and leg load was 52 ± 6 W (P < 0.001). The level of DH, 0.32 ± 0.09 and 0.27 ± 0.08 L during arm and leg exercises, respectively, was not significantly different. However, breathing frequency was greater during arm than during leg exercise (24 ± 1 vs 21 ± 1 breaths per minute, P < 0.01), and the opposite was true for tidal volume (1.56 ± 0.15 vs 1.69 ± 0.14 L, P < 0.01).
At similar ventilation, we found a similar degree of DH during arm and leg CWR tests in patients with mild to very severe COPD. Although differences in breathing pattern were observed between arm and leg exercises, these did not affect the level of DH.
患有慢性阻塞性肺疾病（COPD）的患者在进行手臂运动时比进行腿部运动时报告更多的呼吸困难。呼吸困难的主要原因之一是动态过度充气（DH），这是由气流受限以及通气增加引起的。我们研究的目的是比较手臂和腿部工作时相同通气量（等通气）下的 DH，并研究呼吸模式对 DH 的影响。
13 名临床稳定的轻度至重度 COPD 患者（第 1 秒用力呼气量=59%±21%）参与了这项研究。手臂和腿部等速恒功率（CWR）运动以随机顺序进行，通气量等于 50%的峰值手臂负荷。相应的腿部通气量水平的腿部负荷是从递增腿部测试中确定的。呼吸生理学通过呼吸测量。通过测量休息时和 2 分钟间隔时吸气容量的变化来反映 DH。
在稳定的等通气状态下（手臂和腿部 CWR 测试分别为 37±2 和 36±2 L·min，P>0.05），手臂负荷为 29±5 W，腿部负荷为 52±6 W（P<0.001）。手臂和腿部运动时的 DH 水平分别为 0.32±0.09 和 0.27±0.08 L，无显著差异。然而，手臂运动时呼吸频率高于腿部运动（24±1 比 21±1 次/分钟，P<0.01），而潮气量则相反（1.56±0.15 比 1.69±0.14 L，P<0.01）。
在相同的通气量下，我们发现轻度至重度 COPD 患者在手臂和腿部 CWR 测试中出现了相似程度的 DH。尽管手臂和腿部运动之间观察到呼吸模式的差异，但这些差异并未影响 DH 水平。
