Circadian and gender differences in skin temperature in militaries by thermography

Aim: The purpose of this study was to determine gender differences in skin temperature (Tsk) for 21 regions of interest (ROIs) of the body throughout the day in a military sample using infrared thermography. Methods: The Tsk of 20 male (23.2 ± 2.9 yr) and 20 female (20.5 ± 1.3 yr) Brazilian Air Force Military members were evaluated with four thermograms collected at 7:00 AM (Tsk7) and 7:00 PM (Tsk19) by a Fluke thermal camera. The ROIs analyzed included the abdomen and bilateral anterior and posterior views of the hands, forearms, arms, thighs, and legs. Student’s t-tests were performed on independent samples (a = 0.05). Results: With the exception of the hands, men’s Tsk7 was significantly higher than that of women (p < 0.05). However, in the late evening (Tsk19), only the temperatures of the posterior side of the thigh and leg were significantly lower (p < 0.05) in women. Conclusions: In the early morning, men present a greater average Tsk than women across all evaluated ROIs; however, those differences disappear after 12 h, except for the posterior thighs and legs. The hands were the sole areas showing similar temperatures at both time points.