Hoffmann U, Smerecnik M, Leyk D, Essfeld D
Department of Physiology and Anatomy, Deutsche Sporthochschule Köln, Cologne, Germany.
Int J Sports Med. 2005 Jul-Aug;26(6):426-31. doi: 10.1055/s-2004-821113.
Breath holding maneuvers induce hypoxia, hypercapnia, and various cardiovascular responses typically including increases in total peripheral resistance, mean arterial pressure (MAP) and decreases in heart rate (HR). During dynamic exercise these responses may have a generally negative impact on performance. Moreover, they deserve particular attention in cardiovascular risk subjects. In 26 healthy sport students we studied the HR and MAP effects induced by the combination of dynamic exercise (cycle ergometry, 30 W and 250 W) with 20 s of either respiratory arrest (mouth piece pressure held constant at 20 mm Hg), free breathing, or rebreathing, i. e. periods of unimpeded breathing leading to similar levels of hypercapnia and hypoxia as the respiratory arrest. The measurements yielded no major differences between the conditions of rebreathing and free breathing. In contrast, 20 s of apnea led to a marked increase in MAP and a HR depression at both levels of exercise intensity. Additionally, there was a delayed MAP recovery after this stimulus. The present findings show that breath holding has marked effects on MAP and HR during dynamic exercise, which are essentially independent of the resulting hypoxia and of increases in intrathoracic pressure. The key factor seems to be an increase in total peripheral resistance, probably including a vasoconstriction in the exercising muscles.
屏气动作会引发低氧血症、高碳酸血症以及各种心血管反应，通常包括总外周阻力增加、平均动脉压（MAP）升高和心率（HR）降低。在动态运动过程中，这些反应可能对运动表现产生普遍的负面影响。此外，它们在心血管风险人群中值得特别关注。在26名健康的体育专业学生中，我们研究了动态运动（功率自行车运动，30瓦和250瓦）与20秒的呼吸暂停（口含器压力保持在20毫米汞柱恒定）、自由呼吸或重复呼吸（即无阻呼吸期，导致与呼吸暂停相似程度的高碳酸血症和低氧血症）相结合所引起的心率和平均动脉压的变化。测量结果显示，重复呼吸和自由呼吸两种情况之间没有显著差异。相比之下，在两种运动强度水平下，20秒的呼吸暂停均导致平均动脉压显著升高和心率下降。此外，在此刺激后平均动脉压恢复延迟。目前的研究结果表明，屏气在动态运动过程中对平均动脉压和心率有显著影响，这基本上与由此产生的低氧血症和胸内压升高无关。关键因素似乎是总外周阻力增加，可能包括运动肌肉中的血管收缩。
