Exposure to cold and acute upper respiratory tract infection.

The incidence of acute upper respiratory tract viral infections (URTI) is directly correlated to air temperature with most URTI occurring seasonally in cold weather. This review looks at four types of cold exposure and examines the evidence and possible mechanisms for any relationship to URTI. The effects of cold are discussed as: 1) Chilling of the nose and upper respiratory tract by breathing cold air, 2) Chilling of the mouth and upper digestive tract by ingestion of cold drinks and food, 3) Acute chilling of the body surface, and, 4) Chilling of the body as a whole with a fall in body temperature, hypothermia. Some studies were found to support a relationship between breathing cold air and chilling the body surface with the development of URTI, although this area is controversial. No evidence was found in the literature to support any relationship between ingestion of cold drinks and food and URTI, and similarly no evidence was found to link hypothermia and URTI.