Pilot study: Core Temperature While Swimming in Open Water With And Without a Wetsuit

In the triathlon, swimming is commonly considered as the most dangerous part of a sport due to the high number of fatalities that occur during this portion of the race. One of the risks associated with swimming in open water is the possibility of overheating, particularly when athletes choose to wear long-sleeve wetsuits in warm water. For this reason, the triathlon organizations have set water temperature thresholds in order to minimize the risk of development of hypo/hyperthermia. However, there are limited core temperature data while swimming in a wetsuit in warm water. PURPOSE: To examine core temperature while swimming a 700 m swim in warm open water (27.8° C) with and without a wetsuit while holding a somewhat hard pace. METHODS: One participant was recruited for this pilot study. The participant was an experienced triathlete in open water swimming (age: 60 years, 1.8 m, 89.4 kg). At least 8 hours before the data collection, the participant swallowed an ingestible core temperature pill (BodyCap, France) recording data at 15-s intervals. The participant completed two 700-m open water swim conditions. During the first condition, the participant wore a full sleeve wetsuit (HUUB Design, UK). During the second condition, the participant swam in their regular swimsuit. Swim performance time was recorded with a stopwatch. Rest time was provided between conditions until the core temperature was within 1% above the initial core temperature reading. After the completion of both conditions, core temperature data were downloaded to a hand-held monitor and subsequently uploaded to a computer. The core temperature data for each swim were extracted with maximum temperature, average core temperature, and rate of change of temperature calculated. RESULTS: Swim performance time was 9 min 45 s for wetsuit and 10 min 41 s for no wetsuit conditions. The maximum temperature for wetsuit (37.57° C) and no wetsuit (37.8° C) as well as the average core temperature for wetsuit (37.39° C) and no wetsuit (37.80° C) were qualitatively similar. The rate of temperature change for wetsuit condition (0.27° C/s) and no-wetsuit (0.09° C/s) were qualitatively different. CONCLUSION: As pilot study, it was determined that the rate of change of core temperature may be a critical parameter to examine with a larger group of subjects.