Cold-induced responses in the upper respiratory tract.

Recent investigations have shown that the prevalence of bronchial asthma is higher among skiers exposed to cold and dry air than among nonskiers. The upper airway passages are responsible for warming and humidifying the inhaled air. During exercise in cold and dry air, warming and humidifying of the inhaled air continues in the bronchial tree. Under these conditions both nasal and bronchial mucosa are cooled by inspiratory air and remain cooled throughout the respiratory cycle. The air which reaches the bronchoalveolar air space is at body temperature and fully saturated in all conditions. In this article we briefly review the studies carried out regarding the effects of cold air inhalation on the upper respiratory tract.