Restoration of thermoregulatory response to body cooling by cooling hands and feet.
Deep body temperature fell progressively by 0.5-1.4 degrees C during 3-h immersions in 29 degrees C water. Both in unacclimatized volunteers and, to a lesser degree, in divers in cold-water training, cooling the hands and feet for 1 h in 12 degrees C water during such immersion caused sensation of cold, shivering, and rise in metabolic rate; it caused body temperature to rise in unacclimatized subjects and halted its fall in divers. Tissue conductances generally fell a little in divers but rose in unacclimatized subjects, probably because of muscle blood flow associated with the greater shivering in the latter. Soaking the skin for 4 h produced no major changes in cutaneous thermal sensation assessed in the forearm, though with seawater it sometimes reduced cold sensation and with distilled water sometimes reduced warm sensation, a little. It is concluded that uniform skin temperature of 29 degrees C often induces insufficient heat-gain reflexes to maintain body temperature and that cooling of the extremities can restore adequate thermoregulatory response.
D000328:Adult; D001833:Body Temperature Regulation; D003080:Cold Temperature; D005260:Female; D005528:Foot / Q000502:physiology*; D006225:Hand / Q000502:physiology*; D006801:Humans; D007101:Immersion; D008297:Male; D012879:Skin Physiological Phenomena; D013697:Thermosensing; D013997:Time Factors