Gagnon Dominique D, Pretorius Thea, McDonald Gerren, Kenny Glen P, Giesbrecht Gordon G
Laboratory for Exercise and Environmental Medicine, Health, Leisure and Human Performance Research Institute, University of Manitoba, Winnipeg, Canada.
Aviat Space Environ Med. 2013 Jun;84(6):573-83. doi: 10.3357/asem.3275.2013.
Facial cooling can regulate reflexes of the dive response whereas further body cooling generally induces the cold-shock response. We examined the cardiovascular and ventilatory parameters of these responses during 3-min immersions of the head dorsum, face, and whole head in 17 degrees C water while breathing was maintained.
From a horizontal position, the head was inserted into a temperature controlled immersion tank in which the water level could be changed rapidly. On four occasions, either the head dorsum, face or whole head (prone and supine) were exposed to water.
Mean decrease in heart rate (14%) and increases in systolic (9%) and diastolic (5%) blood pressures were seen during immersion. Relative mean finger skin blood flow had an early transient decrease (31%) for 90 s and then returned to baseline values. A strong transient increase was seen in minute ventilation (92%) at 20 s of immersion via tidal volume (85%). There were no consistent differences between the head dorsum, face, and whole head for all variables in response to immersion.
The cold-shock response (increased minute ventilation and tidal volume) predominated over the dive response in the initial moments of immersion only. The order of emergence of these responses provides further recommendation to avoid head submersion upon cold water entry. It is important to protect the face, with a facemask, and the head dorsum, with an insulative hood, in cold water.
面部冷却可调节潜水反应的反射，而身体的进一步冷却通常会引发冷休克反应。我们在呼吸保持正常的情况下，将头部背部、面部和整个头部浸入17摄氏度的水中3分钟，期间检测了这些反应的心血管和通气参数。
从水平位置开始，将头部插入一个水温可控的浸水箱中，水箱中的水位可以快速变化。共进行了四次实验，分别将头部背部、面部或整个头部（俯卧和仰卧）暴露于水中。
浸入过程中，心率平均下降（14%），收缩压（9%）和舒张压（5%）升高。相对平均手指皮肤血流量在90秒内有早期短暂下降（31%），然后恢复到基线值。浸入20秒时，通过潮气量（85%）观察到分钟通气量有强烈的短暂增加（92%）。在浸入过程中，对于所有变量，头部背部、面部和整个头部之间没有一致的差异。
仅在浸入的最初时刻，冷休克反应（分钟通气量和潮气量增加）比潜水反应更为明显。这些反应出现的顺序为避免冷水进入时头部浸入提供了进一步的建议。在冷水中，使用面罩保护面部和使用隔热帽保护头部背部非常重要。
