International Rhinologic Society Rhinology 0300-0729 2026 09 09 Ambient cold air decreased nasal mucosa blood flow measured by laser Doppler flowmeter EN Y.H. Chu Department of Otolaryngology-Head and Neck Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan D.W. Lu 2 Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan H.W. Wang Department of Otolaryngology-Head and Neck Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan Journal Article 847 10.4193/Rhin09.122 BACKGROUND: With its potentially conflicting physiological roles of both air-conditioning and body-heat recovery, the response of nasal mucosa blood flow (NMBF) to ambient cold air is not well understood. OBJECTIVE: To evaluate the NMBF in response to cold ambient air. METHODS: The NMBF was continuously measured by laser Doppler flowmetry in nine partici- pants exposed to different air temperatures (24°C and 4°C). RESULTS: The NMBF significantly decreased at 4°C compared with that at 24°C (p < 0.01). CONCLUSION: The response to ambient cold air in the nasal microcirculation is similar to that of the body-surface blood vessels, suggesting that body-heat recovery rather than air-conditioning is the predominant function.