Noninvasive Evaluation of the Chronic Influence of Local Air Velocity from an Air Conditioner Using Salivary Cortisol and Skin Caspase-14 as Biomarkers of Psychosomatic and Environmental Stress

OBJECTIVE: To demonstrate the possibility of evaluating the chronic influence of local air velocity from an air conditioner using noninvasive biomarkers. METHODS: Over a consecutive 5-day period, 16 healthy young male adults were exposed to air flow from a whole ceiling-type air conditioner (low local air velocity) and from a commercial concentrated exhaust air conditioner (high local air velocity). Salivary cortisol was used as an index of the psychological effects and caspase-14, collected from the stratum corneum, was used as a marker of environmental stress on the skin. RESULTS: Local air velocity generated from the whole ceiling-type air conditioner where the subject's head was positioned was one-seventh that of the exhaust air conditioner. After exposure to the exhaust air conditioner for 5 days, salivary cortisol decreased significantly from morning to evening and skin caspase-14 gradually increased during the day. A significant increase in hydration index from the morning to the evening was found with the whole ceiling-type air conditioner. CONCLUSION: The effects of chronic exposure to air movement generated by an air conditioner may be quantified by measurement of salivary cortisol and skin caspase-14.