Rüst Christoph Alexander, Knechtle Beat, Rosemann Thomas
Institute of General Practice and for Health Services Research, University of Zurich, Zurich, Switzerland.
Extrem Physiol Med. 2012 Nov 1;1(1):8. doi: 10.1186/2046-7648-1-8.
This case report describes an experienced open-water ultra-endurance athlete swimming in water of 9.9°C for 6 h and 2 min.
Before the swim, anthropometric characteristics such as body mass, body height, skinfold thicknesses, and body fat were determined. During and after the swim, body core (rectum) and body surface (forearm and calf) temperatures were continuously recorded.
The swimmer (53 years old, 110.5 kg body mass, 1.76 m body height, 34.9% body fat, and a body mass index of 35.7 kg/m2) achieved a total distance of 15 km while swimming at a mean speed of 2.48 km/h, equal to 0.69 m/s, in water of 9.9°C. Body core temperature was at 37.8°C before the swim, increased to a maximum of 38.1°C after approximately 20 min of swimming, and then decreased continuously to 36.3°C upon finishing the swim. The lowest body core temperature was 36.0°C between 35 and 60 min after finishing the swim. Sixty minutes after the swim, the body core temperature continuously rose to 36.5°C where it remained. At the forearm, the temperature dropped to 19.6°C after approximately 36 min of swimming and decreased to 19.4°C by the end of the swim. The lowest temperature at the forearm was 17.6°C measured at approximately 47 min before the athlete stopped swimming. At the calf, the temperature dropped to 13.0°C after approximately 24 min of swimming and decreased to 11.9°C at the end of the swim. The lowest temperature measured at the calf was 11.1°C approximately 108 min after the start. In both the forearm and the calf, the skin temperature continuously increased after the swim.
This case report shows that (1) it is possible to swim for 6 h in water of 9.9°C and that (2) the athlete did not suffer from hypothermia under these circumstances. The high body mass index, high body fat, previous experience, and specific preparation of the swimmer are the most probable explanations for these findings.
本病例报告描述了一名经验丰富的公开水域超长耐力运动员在9.9°C的水中游泳6小时2分钟的情况。
游泳前，测定了体重、身高、皮褶厚度和体脂等人体测量特征。游泳期间和之后，持续记录身体核心（直肠）和身体表面（前臂和小腿）温度。
该游泳者（53岁，体重110.5千克，身高1.76米，体脂34.9%，体重指数35.7千克/平方米）在9.9°C的水中以平均速度2.48千米/小时（相当于0.69米/秒）游泳，总距离达到15千米。游泳前身体核心温度为37.8°C，游泳约20分钟后升至最高38.1°C，然后在游完后持续降至36.3°C。游完后35至60分钟时，最低身体核心温度为36.0°C。游完60分钟后，身体核心温度持续升至36.5°C并保持在该水平。在前臂，游泳约36分钟后温度降至19.6°C，游完时降至19.4°C。运动员停止游泳前约47分钟，前臂测得的最低温度为17.6°C。在小腿，游泳约24分钟后温度降至13.0°C，游完时降至11.9°C。开始后约108分钟，小腿测得的最低温度为11.1°C。在前臂和小腿，游泳后皮肤温度均持续上升。
本病例报告表明，（1）有可能在9.9°C的水中游泳6小时，且（2）在此情况下该运动员未出现体温过低。游泳者的高体重指数、高体脂、以往经验和特定准备工作最有可能解释这些结果。
