Human Physiology in an Aquatic Environment
Human Physiology in an Aquatic Environment
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DOI：
10.1002/cphy.c140018
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发表时间：
2015-10-01
影响因子：
5.8
通讯作者：
Zamparo, Paola
中科院分区：
文献类型：
--
作者：
Pendergast, David R.;Moon, Richard E.;Zamparo, Paola
水覆盖了地球的70%以上，有不同的深度和温度，包含了地球上的大部分资源。头出水浸泡（HOWI）或在不同深度（潜水）浸泡在热中性（TN）温度的水中会引起深刻的心肺、内分泌和肾脏反应。血液向胸腔的易位和细胞向血管室自身输注液体导致血浆容量升高，导致心搏容量和输出量增加，某些组织出现高灌注。肺动脉和毛细血管静水压力增加，导致肺活量下降，有可能发生肺水肿。心房拉伸和动脉压力升高引起反射性自主神经反应，导致内分泌变化，使血浆容量和动脉压力恢复到浸泡前的水平。血浆容量通过反射利尿和钠尿调节。静水压力也会导致胸部的弹性负荷，增加呼吸功、能量消耗，从而导致血液流向呼吸肌。与TN相比，HOWI中水温的降低不影响心输出量；然而，它们会影响心率以及肌肉和脂肪血流量的分布。肌肉血流量减少导致最大耗氧量减少。水的性质决定了在水中运动（如游泳和水上活动）时的机械负荷和生理反应。淹没引起的静水压力增加不影响冲程体积；然而，进行性心动过缓会减少心输出量。在潜水过程中，必须吸入压缩气体，这可能会导致氧中毒，氮气导致麻醉，减压过程中和之后的组织和血管气泡可能会引起关节和神经系统疼痛。(C) 2015年美国生理学会。
Water covers over 70% of the earth, has varying depths and temperatures and contains much of the earth's resources. Head-out water immersion (HOWI) or submersion at various depths (diving) in water of thermoneutral (TN) temperature elicits profound cardiorespiratory, endocrine, and renal responses. The translocation of blood into the thorax and elevation of plasma volume by autotransfusion of fluid from cells to the vascular compartment lead to increased cardiac stroke volume and output and there is a hyperperfusion of some tissues. Pulmonary artery and capillary hydrostatic pressures increase causing a decline in vital capacity with the potential for pulmonary edema. Atrial stretch and increased arterial pressure cause reflex autonomic responses which result in endocrine changes that return plasma volume and arterial pressure to preimmersion levels. Plasma volume is regulated via a reflex diuresis and natriuresis. Hydrostatic pressure also leads to elastic loading of the chest, increasing work of breathing, energy cost, and thus blood flow to respiratory muscles. Decreases in water temperature in HOWI do not affect the cardiac output compared to TN; however, they influence heart rate and the distribution of muscle and fat blood flow. The reduced muscle blood flow results in a reduced maximal oxygen consumption. The properties of water determine the mechanical load and the physiological responses during exercise in water (e.g. swimming and water based activities). Increased hydrostatic pressure caused by submersion does not affect stroke volume; however, progressive bradycardia decreases cardiac output. During submersion, compressed gas must be breathed which introduces the potential for oxygen toxicity, narcosis due to nitrogen, and tissue and vascular gas bubbles during decompression and after may cause pain in joints and the nervous system. (C) 2015 American Physiological Society.