Paulev P E, Pokorski M, Honda Y, Morikawa T, Sakakibara Y, Tanaka Y
University of Copenhagen, PANUM, Sports/Cybernetics, Copenhagen, Denmark.
Jpn J Physiol. 1990;40(1):117-25. doi: 10.2170/jjphysiol.40.117.
We measured stroke volume (SV), heart rate (HR), cardiac output (Q), arterial pressure and intrapulmonic (mouth) pressure in four healthy, male subjects during simulated swimming (i.e., performing crawl movements with the legs continuously at a constant rhythm) with and without apnea (water temperature: 31 degrees C). We wanted to see whether the exercise tachycardia response persisted, or whether the HR decreased during apnea, just as in the "diving response" of diving animals. The SV and the Q fell to half its value in the control phase (i.e., swimming with normal breathing), when the 15-s apnea was performed at a high mouth-pressure; at low mouth-pressure, SV and Q hardly changed. These results are replicates of our previous findings in man during rest in air. Due to the light work, HR increased slightly from rest, but the exercise HR did not change much during apnea with or without high mouth-pressure. The results show that man tends to preserve his exercise HR response, and does not react as an oxygen-conserving animal, whether he is in air or in water under these conditions. However, man, as well as diving animals, may well have a "diving response" as an emergency reaction, which may not be restricted to only the water environment.
我们在四名健康男性受试者模拟游泳（即双腿持续以恒定节奏进行爬泳动作）过程中，分别在有呼吸和无呼吸（水温：31摄氏度）的情况下，测量了每搏输出量（SV）、心率（HR）、心输出量（Q）、动脉压和肺内（口腔）压。我们想看看运动性心动过速反应是否持续存在，或者心率在无呼吸期间是否会像潜水动物的“潜水反应”那样下降。当在高口腔压力下进行15秒的无呼吸时，SV和Q降至对照阶段（即正常呼吸游泳）时其值的一半；在低口腔压力下，SV和Q几乎没有变化。这些结果重复了我们之前在空气中休息的人体研究结果。由于运动强度较小，心率从休息时略有增加，但在有无高口腔压力的无呼吸过程中，运动心率变化不大。结果表明，在这些条件下，无论处于空气中还是水中，人类倾向于保持其运动心率反应，并且不会像保氧动物那样做出反应。然而，人类以及潜水动物很可能有作为应急反应的“潜水反应”，这种反应可能不限于仅在水环境中出现。
