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Scientific rationale for changing lower water temperature limits for triathlon racing to 12°C with wetsuits and 16°C without wetsuits
  1. Jane Saycell,
  2. Mitch Lomax,
  3. Heather Massey,
  4. Mike Tipton
  1. Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, UK
  1. Correspondence to Jane Saycell, Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Portsmouth PO1 2UP, UK; jane.saycell{at}


Objectives To provide a scientific rationale for lower water temperature and wetsuit rules for elite and subelite triathletes.

Methods 11 lean, competitive triathletes completed a 20 min flume swim, technical transition including bike control and psychomotor testing and a cycle across five different wetsuit and water temperature conditions: with wetsuit: 10°C, 12°C and 14°C; without wetsuit (skins): 14°C and 16°C. Deep body (rectal) temperature (Tre), psychomotor performance and the ability to complete a technical bike course after the swim were measured, as well as swimming and cycling performance.

Results In skins conditions, only 4 out of 11 athletes could complete the condition in 14°C water, with two becoming hypothermic (Tre<35°C) after a 20 min swim. All 11 athletes completed the condition in 16°C. Tre fell further following 14°C (mean 1.12°C) than 16°C (mean 0.59°C) skins swim (p=0.01). In wetsuit conditions, cold shock prevented most athletes (4 out of 7) from completing the swim in 10°C. In 12°C and 14°C almost all athletes completed the condition (17 out of 18). There was no difference in temperature or performance variables between conditions following wetsuit swims at 12°C and 14°C.

Conclusion The minimum recommended water temperature for racing is 12°C in wetsuits and 16°C without wetsuits. International Triathlon Union rules for racing were changed accordingly (January 2017).

  • swimming
  • triathlon
  • aquatic sports
  • Ioc
  • thermoregulation

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  • Contributors All coauthors contributed to the study design and data collection. JS processed and analysed the data and wrote the draft of the manuscript. All authors contributed to revising the draft of the manuscript.

  • Funding The study was funded by the Joint Medical Committee of the International Olympic Committee, Federation Internationale de Natation and the International Triathlon Union.

  • Competing interests None declared.

  • Patient consent Not required.

  • Ethics approval The study was approved by The University of Portsmouth Science Faculty Research Ethics Committee (code 2014–087).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement All unpublished data are available on request to the corresponding author.