Qualitative identification and characterisation of self-reported symptoms arising in humans during experimental exposure to cold air.

ABSTRACT

BACKGROUND: Exposure to cold air is associated with increased morbidity and mortality in the general population. It is difficult to study the effects of whole-body exposure to cold air under controlled conditions in real life. OBJECTIVES: The aim of this study was to (1) explore and describe the experience of symptoms in humans during experimental and controlled exposures to cold air, by using controlled environmental chamber exposures and qualitative methodology, and to (2) categorise the symptoms. METHOD: The study used a randomised, double blind design, in which 34 subjects undertook rest and moderate-intensity exercise in an environmental chamber set to two or three different temperatures (0, -10, and -17°C) on separate occasions. During the chamber exposures, subjects were interviewed. Qualitative content analysis was selected as the method of analysis. FINDINGS: Subjects reported 50 distinct symptoms during the exposures. The symptoms were grouped into ten sub-categories and two major categories; airway versus whole-body symptoms. CONCLUSION: We have identified a broad range of symptoms in humans undertaking rest and moderate-intensity exercise at sub-zero temperatures. The symptoms and their categories may well be used to more extensively and quantitatively map cold-induced morbidity.