McMahon Michael E, Boutellier Urs, Smith Richard M, Spengler Christina M
Exercise Physiology, Swiss Federal Institute of Technology and University of Zurich, Switzerland.
J Exp Biol. 2002 Dec;205(Pt 24):3937-43. doi: 10.1242/jeb.205.24.3937.
Well-trained endurance athletes frequently have a lower peripheral chemoreceptor (pR(c)) sensitivity and a lower minute ventilation (E) during exercise compared to untrained individuals. We speculated that the decreased pR(c) response may be specifically associated with repeated exposure to the high rates of ventilation occurring during exercise training. We therefore examined the effect of respiratory muscle training (RMT; 20x 30 min sessions of voluntary normocapnic hyperpnea) on the pR(c) sensitivity during exercise and on cycling performance. RMT was chosen to achieve a high E, similar to that of heavy exercise, while avoiding the other accompanying effects of whole body exercise. 20 trained male cyclists were randomized into RMT (N=10) or control (N=10) groups. Subjects' pR(c) response was assessed by a modified Dejours O(2) test (10-12 breaths of 100% O(2), repeated 4-6 times) during cycling exercise at 40% of the maximal work capacity ((max)). Cycling performance was measured during a cycling test to exhaustion (85% (max)). The RMT group exhibited a significantly reduced pR(c) sensitivity (mean +/- S.D.) compared to the control group (-5.8+/-6.0% versus 0.1+/-4.6%, P<0.5). Cycling endurance improved significantly after RMT in comparison to the control group (+3.26+/-4.98 versus -1.46+/-3.67 min, P<0.05). However, these changes in pR(c) response were not significantly correlated with exercise ventilation or cycling endurance time. We conclude that the high levels of ventilation achieved during exercise, as simulated by RMT in this study, appear to be accompanied by a reduction in pR(c) sensitivity; however, the role of the pR(c) in the control of ventilation during exercise seems to be minor.
与未经训练的个体相比，训练有素的耐力运动员在运动过程中通常外周化学感受器（pR(c)）敏感性较低，分钟通气量（E）也较低。我们推测，pR(c)反应降低可能与反复暴露于运动训练期间出现的高通气率有特定关联。因此，我们研究了呼吸肌训练（RMT；20次，每次30分钟的自主正常碳酸血症性深呼吸）对运动期间pR(c)敏感性和骑行表现的影响。选择RMT是为了达到与剧烈运动相似的高E水平，同时避免全身运动的其他伴随效应。20名训练有素的男性自行车运动员被随机分为RMT组（N = 10）或对照组（N = 10）。在以最大工作能力（(max)）的40%进行自行车运动期间，通过改良的德茹尔O(2)测试（10 - 12次100% O(2)呼吸，重复4 - 6次）评估受试者的pR(c)反应。在进行至力竭的自行车测试（85% (max)）期间测量骑行表现。与对照组相比，RMT组表现出pR(c)敏感性显著降低（平均值±标准差）（-5.8±6.0%对0.1±4.6%，P < 0.5）。与对照组相比，RMT后骑行耐力显著提高（+3.26±4.98对 - 1.46±3.67分钟，P < 0.05）。然而，pR(c)反应的这些变化与运动通气或骑行耐力时间无显著相关性。我们得出结论，本研究中通过RMT模拟的运动期间达到的高通气水平似乎伴随着pR(c)敏感性降低；然而，pR(c)在运动期间通气控制中的作用似乎较小。
