World Aquatics calls for OWS heat limits studies

Swimming's governing body is to enhance athlete safety in open-water competitions, launching a comprehensive Request for Proposal this week to commission new research on Safe Maximum Water Temperature Limits.

World Aquatics currently sets a maximum water temperature limit of 31.0°C for open water swimming competitions. This standard was established following comprehensive research conducted by the University of Otago in 2013 for the global federation, World Triathlon, and the International Olympic Committee. This testing examined swimmers completing swims of various durations (20, 60, and 120 minutes) at water temperatures ranging from 20°C to 32°C under outdoor-relevant ambient conditions.

Now, the federation has launched a fresh call for updated research in a proactive approach to athlete safety, noting that thermal stress in aquatic sports requires a specialised understanding, distinct from land-based endurance activities. The project aims to address several critical questions, including: How do water temperature, ambient conditions, and humidity collectively affect athlete safety and performance? Which physiological and demographic factors shape thermal tolerance in competitors? And what evidence-based recommendations will support improved competition guidelines?

World Aquatics further invites leading institutions and researchers worldwide to submit proposals, showcasing their expertise in thermal physiology, aquatic sports, and innovative competition simulation methods and comprehensive safety protocols for research involving human subjects. Deadline for proposals is 15 April. 

Heat protocols for the demanding water sport, which can often last two hours, were brought to attention following the death of American Fran Crippen in 2010 during a race in Dubai. After the incident, Water Aquatics, then Federation Internationale de Natation, implemented rule 5.5 stating that the water temperature cannot be below 16°C and cannot be above 31°C. The race's winner, Thomas Lurz, noted back then that "the water was amazingly hot…There were many swimmers who had serious problems in the water." Three other swimmers were taken to a hospital.