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Impact of a 10,000-m Cold-Water Swim on Norwegian Naval Special Forces Recruits

Fall 2021

Melau J, Hisdal J, Solberg PA. 21(3). 55 - 59. (Journal Article)


Background: Special Operation Forces (SOF) operate regularly in extreme environmental conditions that may affect tactical and physical performance. The main aims of the present study were to elucidate the impact of a long cold-water swim on SOF recruits' dexterity, performance, and reaction time. Material and Methods: Eleven recruits from Norwegian Naval Special Operation Command (NORNAVSOC) that were participating in a 10,000-m open water swim with a dry suit in 5°C cold water volunteered to participate in this study. The exercise was part of their training. Grip strength, lower body power, and dexterity were measured before, immediately after, and 24 hours after the swim. In addition, core and skin temperatures were measured continuously during the swim and until 45 minutes after the swim. Results: After the swim, moderate to large reductions in core temperature, lower body power, and reaction time were observed. Moreover, very large to extremely large reductions in skin temperature, grip strength, and dexterity were also observed. Conclusion: These results demonstrate that exposure to a 10,000-m swim in 5°C water using standard equipment led to a significant drop in the recruits' temperature and performance. These findings could have a meaningful impact on the planning of training, operations, and gear used for SOF.

Keywords: stress hormones; body temperature; skin temperature; military medicine; swimming; physical fitness; combat swimmer; combat diver

PMID: 34529806

DOI: 10.55460/QE23-511P

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