The physiological impact of high altitude on nasal and lower airway parameters.

The aim of this study was to investigate the impact of high altitude on nasal and lower airway parameters in a healthy population. This was a prospective study of 61 individuals who climbed to the summit of Mount Kackar, at 3,937 m. Peak nasal inspiratory flow rates were recorded in all participants at sea level and at the summit. In 32 participants who ascended to the summit, sea-level and summit peak expiratory flow rates and olfactory function were evaluated. A rise in altitude significantly decreased peak nasal inspiratory flow by a mean of 27.43%. Mean peak expiratory flow values measured at the summit were 8.94% lower than basal values. Between-value differences were statistically significant (p < 0.001, p < 0.05). At high altitude, there was a significant decrease in olfactory function, as determined by a significant reduction in smell detection (p < 0.05) and smell identification (p < 0.05). The effect of high altitude on nasal function was found to parallel that of the effect on lower airway function, together accounting for an adverse effect on airway flow rates. The nasal mucosa responded to high altitude with an increase in airway resistance and a consequent impaired sense of smell.