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

Abstract

ObjectivesTo determine the influence of a patent foramen ovale (PFO) and fibroblast growth factor-21 (FGF-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. DesignAn experimental study comparing the Tc responses between divers with (n = 17) and without a PFO (n = 14). MethodsA total of 31 divers participated in the study. Tc was measured pre- and post-dive using a telemetric pill. Additionally, blood was drawn pre-dive and ~1–2 h post-dive for measurement of FGF-21. ResultsThere was no influence of PFO on the Tc responses during SCUBA diving in either dive profile (p > 0.05). Additionally, there was no influence of SCUBA diving on FGF-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 body surface area to mass ratio and ∆Tc/min (Fig. 1E; r2 = 0.2812, p = 0.0032). ConclusionsTc responses were most strongly associated when considering anthropometric characteristics and wetsuit thickness. These data suggest that core temperature regulation during recreational SCUBA diving can be facilitated in part by the appropriate choice of wetsuit thickness for a give set of anthropometric characteristics.