Research on cold water swimming and core temperature

bruckbruck San FranciscoMember

An interesting new study by Tara Diversi and colleagues in Extreme Physiology & Medicine.

Core temperature rate of decline was slower in the first 3 h compared to the last 3 h of the swim. Older age was significantly correlated to TC change and SR change. Absolute and percentage body fat (BF) were not significantly associated with higher TC. Mean SR over the 6-h swim was 57.8 spm (range 48–73 spm), and a significant decline in SR was observed over the 6 h. A strong, positive correlation was found between SR change between 3 and 6 h and TC over the 6 h and TC from 3–6 h.



  • JenAJenA Charter Member

    That's a great article, @bruck! Too bad about the small sample size of 9, but really good to see the analysis.

  • SpacemanspiffSpacemanspiff Dallas, TexasSenior Member

    Interesting there was no correlation between bioprene and core temperature change--second largest drop in core temp came from swimmer with the highest body fat (43%). Is it a myth, then? Or just too small a sample size?


    "Lights go out and I can't be saved
    Tides that I tried to swim against
    Have brought be down upon my knees
    Oh I beg, I beg and plead..."

  • ColmBreathnachColmBreathnach Charter Member

    was there a measure of relative effort of swimmers, ie swimming hard or easy, as this would also contribute to temperature drop?

  • JSwimJSwim western Maryland, USMember

    They used stroke rate (SR), and SR changes, as a gauge of effort level:

    In freestyle swimming, increased SR is associated with increased metabolic heat production and typically results in an increased velocity [47]. Stroke rate is also related to energy output, and thus a decline in SR is generally indicative of a swimmer’s state of fatigue and performance [48].

    Life begins at the end of your comfort zone. --Neale Donald Walsch

  • Hi All,

    This was one of our small studies, and it's very difficult to make conclusions based on these 9 swimmers. We did a study with 21 swimmers over an 8 hour swim, but had a malfunction, so we only have relative rate of decline and not absolute numbers. So the likelihood is that this data won't be published. This gives us something to think about though. Anecdotally, from observing these two studies, it is obvious that cold tolerance and thermoregulation are not always the same. We didn't have a measure to test it, but body fat seemed to allow people to tolerate the cold, whilst not always protecting them from core temperature decline. Also, FYI, for analysis when we took out the outlier with high BF%, the results still showed no correlation to body fat %. I'm behind on my analysis, but we hope to have some at least another paper out this year. Personally, if I were looking at this research to see how it could help me, I wouldn't start losing weight and thinking I could tolerate cold water swims. We know lean people can do cold water swims, but there are other contributing factors such as muscle mass, speed, nutritional intake and exposure to cold water that need to be accounted for that are not explored in this research.

    Happy Swimming


  • Anectdotally , we have have had uh, rather LARGE people who are not acclimated still get hypothermia so BF% is not always an indicator.


    Looking for the next big thing.. ... @suzieswimcoach

  • Using A&D (10% lanolin) or expensive 90% lanolin helps me.

  • tortugatortuga Senior Member

    Thanks for sharing this very interesting study.

  • andissandiss Senior Member

    Interesting- great post!

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