Cold air-provoked respiratory symptoms: the mechanisms and management.

OBJECTIVES: To describe the mechanisms and management of cold air-provoked respiratory symptoms. STUDY
DESIGN: A literature review.
METHODS: The review includes human epidemiological studies, human and animal experimental studies, as well as human studies about management of the cold air-provoked respiratory symptoms.
RESULTS: Cold air is unlikely to be a causal factor initiating respiratory diseases but a symptom trigger. In the present review, the airway responses beyond these symptoms were divided into three types. The short-term responses are those that develop within minutes in response to sudden cooling of the airways. Subjects with asthma or rhinitis are especially prone to these responses. The long-term responses are those that develop in response to repeated and long-standing cooling and drying of the airways, usually in endurance athletes. Finally, there are the physiological, reflex-mediated lower-airway responses to cooling of the skin or upper airways.
CONCLUSIONS: The mechanisms beyond cold air-provoked respiratory symptoms vary considerably and mainly depend on the individual's susceptibility and the ventilation level during the cold exposure. An understanding of these mechanisms is essential for successful management of the symptoms.