Prevalence of hypothermia and critical hand temperatures during military cold water immersion training.

Cold-weather military operations can quickly undermine warfighter readiness and performance. Specifically, accidental cold-water immersion (CWI) contributes to rapid body heat loss and impaired motor function. This study evaluated the prevalence of hypothermia and critical hand temperatures during CWI. One-hundred seventeen (N = 117) military personnel (mean ± SD age: 27 ± 6 yr, height: 176 ± 8 cm, weight: 81.5 ± 11.6 kg) completed CWI and rewarming during cold-weather training, which included a 10-min outdoor CWI (1.3 ± 1.4°C) combined with cold air (−4.2 ± 8.5°C) exposure. Following CWI, students removed wet clothing, donned dry clothing, and entered sleeping systems. Core (T_c) and hand (T_hand) temperatures were recorded continuously during the training exercise. T_c for 96 students (mean ± SD lowest T_c = 35.6 ± 0.9°C) revealed that 24 students (25%) experienced T_c below 35.0°C. All of 110 students (100%) experienced T_hand below 15.0°C, with 71 students (65%) experiencing T_hand at or below 8.0°C. Loss of hand function and hypothermia should be anticipated in warfighters who experience CWI in field settings. Given the high prevalence of low T_hand, focus should be directed on quickly rewarming hands to recover function. [ABSTRACT FROM AUTHOR]