“…The reliability of the body temperature measurement, however, is not only related to metrological issues, but also to the intrinsic complexity and variability of the “subjective” measurand and to the homeostatic mechanisms of body thermoregulation [ 11 , 12 ]. This process is under hypothalamic control, and it is conditioned by several individual factors (e.g., comorbidities, age, physical activity, digestion, stress, use of drugs and smoking), temporal variables (e.g., circadian rhythm, menstrual cycle), spatial variables (e.g., body and skin) and environmental conditions (e.g., indoor/outdoor) [ 13 , 14 ]. In measuring body temperature, it is worthy to distinguish the core temperature from the peripheral one.…”