Dipartimento di Scienze Applicate ai Biosistemi, Sezione di Fisiologia Umana, Università di Cagliari, Via Porcell 4, 09124 Cagliari, Italy.
Eur J Appl Physiol. 2012 Feb;112(2):543-54. doi: 10.1007/s00421-011-2006-0. Epub 2011 May 24.
The diving response is the sequence of cardiovascular, respiratory and metabolic adjustments produced by apnoea and further strengthened by cooling of the facial area and/or hypoxia. This study aimed at comparing the cardiovascular response to diving of trained divers with that of a control group. In this order, 14 trained divers were compared with 14 non-divers. By means of impedance cardiography and continuous monitoring of arterial pressure, hemodynamic data were collected during three different experimental sessions. Each session included a cycle-ergometer exercise against a workload of 0.5 W kg(-1) of body mass, pedalling in a steady-state condition. During exercise, each subject randomly accomplished 40 s of breath-hold exercise with face immersion (test A) or in air (test B). A control exercise test with normal breathing (test C) was also performed. Divers showed a faster onset of bradycardic response (ANOVA, P < 0.01) and a faster adjustment in systemic vascular resistance (P < 0.001 for divers vs. controls) than did non-divers. Moreover, cardiac output decreased only in divers during the first phase of test A (P < 0.01 for divers vs. controls). The most striking findings were that divers showed a more rapid cardiovascular adjustment with respect to controls, in particular in heart rate and systemic vascular resistance; moreover, with continued apnoea, a delayed increase in myocardial performance and stroke volume occurred and obscured the cardiovascular effects of the diving response.
潜水反应是由屏气引起的一系列心血管、呼吸和代谢调整，进一步通过面部区域的冷却和/或缺氧而加强。本研究旨在比较有经验的潜水员与对照组潜水员的潜水心血管反应。为此，比较了 14 名训练有素的潜水员和 14 名非潜水员。通过阻抗心动描记术和动脉血压的连续监测，在三个不同的实验期间收集了血流动力学数据。每个期间包括在 0.5 W kg(-1)体重负荷下进行的自行车测力计运动，稳定状态下踏车。在运动期间，每个受试者随机完成 40 秒的闭气运动（测试 A）或在空气中（测试 B）。还进行了正常呼吸的对照运动测试（测试 C）。与非潜水员相比，潜水员的心动过缓反应起始更快（ANOVA，P < 0.01），全身血管阻力调整更快（潜水员与对照组相比，P < 0.001）。此外，在测试 A 的第一阶段，只有潜水员的心输出量下降（潜水员与对照组相比，P < 0.01）。最显著的发现是，与对照组相比，潜水员表现出更快的心血管调整，特别是在心率和全身血管阻力方面；此外，随着持续的屏气，心肌性能和每搏量的延迟增加发生并掩盖了潜水反应的心血管效应。
