A biological perspective is used to understand thermal sensation. The main premise is that thermal sensation serves an organism for the regulation of body temperature. A biological concept related to this premise is the physiological thermoneutral zone (TNZ). Within the TNZ the body can adjust body tissue insulation to maintain thermal balance and a stable core temperature. The approach presented here is based on the assumption that humans express neutral thermal sensation near the centre of their TNZ. To test this hypothesis, dTNZ(op) is defined as the distance between measured operative temperature and the centre of the TNZ, and dTNZ(sk) as the distance between measured mean skin temperature and the centre of the TNZ. The TNZ centre is ca...