Comparison of insulation provided by dry or wetsuits among recreational divers during cold water immersion (< 5°C)

Background: Divers thermal status influences susceptibility to decompression sickness hence the need for proper insulation during immersion in cold water. However, there is a lack of data on thermal protection provided by diving suits, hence this study. Materials and methods: Two different groups of divers wearing either a wetsuit (n = 15) or a dry suit (n = 15) volunteered for this study. Anthropometric data and dive experience were recorded; skin temperatures at the cervical-supraclavicular (C-SC) area and hands were assessed through high-resolution thermal infrared imaging taken pre- and post-dive. Results: As far as anthropometrics, pre-dive C-SC temperatures (37.0 +/- 0.4 degrees C), depth (dry: 43 +/- 4.6 mfw vs. wet: 40.3 +/- 4.0 mfw) and water temperature exposure (4.3 degrees C) are concerned, both groups were comparable. Total dive time was slightly longer for dry suit divers (39.6 +/- 4.0 min vs. 36.5 +/- 4.1 min, p = 0.049). Post-dive, C-SC temperature was increased in dry suit divers by 0.6 +/- 0.6 degrees C, and significantly decreased in wetsuit divers by 0.8 +/- 0.6 degrees C. The difference between groups was highly significant (dry: 37.5 +/- 0.7 degrees C vs. wet: 36.2 +/- 0.7 degrees C, p = 0.004). Hand's temperature decreased significantly in both groups (dry: 30.3 +/- +/- 1.2 degrees C vs. wet: 29.8 +/- 0.8 degrees C, p = 0.33). Difference between groups was not significant. Conclusions: Medium-duration immersion in cold water (< 5 degrees C), of healthy and fully protected subjects was well tolerated. It was demonstrated that proper insulation based on a three-layer strategy allows maintaining or even slightly improve thermal balance. However, from an operational point of view, skin extremities are not preserved.