School of Human Kinetics, The University of British Columbia, Vancouver, British Columbia, Canada.
Med Sci Sports Exerc. 2011 Sep;43(9):1666-74. doi: 10.1249/MSS.0b013e318214679d.
Expiratory flow limitation (EFL) can occur in healthy young women during exercise. We questioned whether the occurrence and severity of EFL were related to aerobic fitness or anatomical factors.
Twenty-two healthy young (<40 yr) women performed a progressive cycle test to exhaustion. The subjects' maximum expiratory flow-volume curve was compiled from several effort-graded vital capacity maneuvers before and after exercise. The maximum expiratory flow-volume curve, along with inspiratory capacity maneuvers, was used to determine lung volumes and expiratory flows and to quantify EFL. To determine relative airway size, we used a ratio sensitive to both airway size and lung volume, called the dysanapsis ratio. The subjects were partitioned into two groups based upon the appearance of >5% EFL.
Ten subjects showed EFL during exercise. Forced vital capacities (4.4 ± 0.4 vs 3.7 ± 0.4 L, P < 0.001) and forced expiratory flows for any given lung volume were significantly larger in the non-expiratory flow-limited (NEFL) group. The NEFL group's dysanapsis ratio was significantly larger than that of the EFL group (0.27 ± 0.06 vs 0.21 ± 0.04, respectively, P < 0.05), indicating larger airways in the NEFL group. There was no difference between the NEFL and EFL groups with respect to maximal aerobic capacity (50.8 ± 10.0 vs 46.7 ± 5.9 mL·kg(-1)·min(-1), respectively, P = 0.264). At peak exercise, the NEFL group had a significantly higher end-expiratory lung volume than the EFL group (40.1% ± 4.8% vs 33.7% ± 5.7% FVC, respectively, P < 0.05).
We conclude that EFL in women can largely be explained by anatomical factors that influence the capacity to generate flow and volume during exercise rather than fitness per se.
在运动过程中，健康的年轻女性可能会出现呼气流量受限（EFL）。我们质疑 EFL 的发生和严重程度是否与有氧适能或解剖因素有关。
22 名健康的年轻（<40 岁）女性进行了递增负荷的踏车运动直至力竭。在运动前后，通过几次努力分级肺活量测定，编制受试者的最大呼气流量-容积曲线。使用最大呼气流量-容积曲线和吸气量测定，来确定肺容积和呼气流量，并量化 EFL。为了确定相对气道大小，我们使用了一个对气道大小和肺容积都敏感的比值，称为非对称比。根据 EFL 增加>5%的情况，将受试者分为两组。
10 名受试者在运动过程中出现 EFL。在非呼气流量受限（NEFL）组，用力肺活量（4.4±0.4 比 3.7±0.4 L，P<0.001）和任何给定肺容积的用力呼气流量均显著较大。NEFL 组的非对称比明显大于 EFL 组（分别为 0.27±0.06 和 0.21±0.04，P<0.05），表明 NEFL 组的气道较大。NEFL 组和 EFL 组之间的最大有氧能力（分别为 50.8±10.0 和 46.7±5.9 mL·kg-1·min-1，P=0.264）没有差异。在运动峰值时，NEFL 组的呼气末肺容积明显高于 EFL 组（分别为 40.1%±4.8%和 33.7%±5.7% FVC，P<0.05）。
我们的结论是，女性的 EFL 很大程度上可以用影响运动时产生流量和容积能力的解剖因素来解释，而不是单纯的适应能力。
