A Comparative Study of Two Ambulatory Core Temperature Assessment Methods
Résumé
Highlights • ZHF sensor performance level appears as similar in both ambient conditions. • ZHF temperature is not reliable with intestinal temperature during exercise. • Heterogeneity of individual ZHF temperature responses is significant. • Forehead core-to-skin gradient indicates endurance performance level in the heat. Graphical abstract Abstract Background. Given the need to identify reliable non-invasive solutions for core temperature ambulatory monitoring, the purpose of this study was to evaluate the performance of zero-heat-flux (ZHF) temperature sensor on the forehead (T COzhf) by comparing it with intestinal temperature (T COpill) in different ambient and physiological conditions. Methods. Seven trained male subjects were followed during a 45-min rest period (STA) and a 25-min self-regulated cycling exercise performed in neutral (TMP, 22.8 • C) and hot (HOT, 38.5 • C) ambient temperature. Results. T COzhf values differed from T COpill of −0.23 ± 0.13 in STA, 0.15 ± 0.30 • C in TMP and 0.28 ± 0.38 • C in HOT. The 95% limits of agreement showed an acceptable bias between T COzhf and T COpill in STA (±0.26 • C), but not in TMP and HOT (±0.60 and ±0.75 • C). Conclusion. The non-invasive ZHF sensor gave an accurate estimation of T COpill in steady state but not during exercise. However, complementary results let suppose that ZHF performance is not affected by ambient conditions and could be a relevant alternative for deep body temperature measurement during whole-body heat stress.