The maintenance of core temperature in SCUBA divers: Contributions of anthropometrics, patent foramen ovale, and non-shivering thermogenesis

Objectives: To determine the influence of a patent foramen ovale and fibroblast growth factor-21 on core temperature (Tc) responses in SCUBA divers. Additionally, we aimed to quantify the individual and combined influences of wetsuit thickness and anthropometric data on Tc changes during the dives. Design: An experimental study comparing the Tc responses between divers with (n = 17) and without a patent foramen ovale (n = 14). Methods: A total of 31 divers participated in the study. Tc was measured pre- and post-dive in 17–18 °C sea water using a telemetric pill. Additionally, blood was drawn pre-dive and ~ 1–2 h post-dive for measurement of fibroblast growth factor-21. Results: There was no influence of a patent foramen ovale on the Tc responses during SCUBA diving in either dive profile (p > 0.05). Additionally, there was no influence of SCUBA diving on fibroblast growth factor-21 concentrations (p > 0.05). The strongest positive and significant associations with the ∆ Tc/min were found when multiplying wetsuit thickness in millimeters by body mass (r² = 0.3147, p = 0.0010), BMI (r² = 0.3123, p = 0.0011), and body surface area (r² = 0.2877, p = 0.0019). There was a significant, negative linear relationship between the body surface area to mass ratio and ∆ Tc/min (r² = 0.2812, p = 0.0032). Conclusions: These data suggest that Tc regulation during recreational SCUBA diving can be facilitated in part by the appropriate choice of wetsuit thickness for a given set of anthropometric characteristics.