Changes in peripheral IR thermography and energy expenditure on cooling in men and women following sustained strenuous activity in Antarctica

We studied pre- to post-expedition changes in hand temperature measured by infrared (IR) thermography and energy expenditure during whole body cooling of Inspire-22 participants (6 M,3 F). Measurements were made in a whole-body calorimeter at the end of a 36-h protocol when the ambient temperature was reduced by ≈ 5.5 °C over a period of 2 h after which IR images of both hands were taken. After 1-h of re-warming, the imaging was repeated. The mean temperature of the finger and non-finger regions were determined. A line-of-best-fit and its 95% CI were used to estimate the change in energy expenditure (EE) for 100 min of cooling. Pre-expedition 5 participants showed an increased, 2 no-change and 2 decreased EE; post-expedition the corresponding values were 5, 1 and 3 respectively. There was no difference in these proportions between pre- and post-expedition measurements (χ2; p > 0.05). An Applied Rank Transform non-parametric ANOVA for small samples found no significant difference in the cool-warm temperatures for sex of the participants nor whether measurements were made pre- or post-expedition (p > 0.05). Graphical analysis showed no association between the change in EE and the change in hand-to-background temperature on cooling suggesting reduced peripheral circulation was not an explanation for reduced EE on cooling.