Heat exchange in the nose.

Studies of the effects of nasal respiration on the lower respiratory tract, and on metabolic processes generally, have largely been confined to those occurring during inspiration. Expiration through the nose has equally profound effects and has been studied in detail in some animals. Under certain circumstances both heat and water loss from the body can be altered by changes in the nasal mucosa. These changes appear to be under the control of the autonomic nervous system and are influenced by the need to balance heat loss with heat production. The clinical and ecogeographical significance of these findings are discussed.