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

Abstract

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.

Nasal Function Changes at High Altitude

“…The present result was confirmed at the multivariate analysis, which showed that PNIF changed with altitude independently from the effect of all the other variables considered in the model (Table 3). Even though PNIF values have been found to decrease with the increase of the altitude, 6 other authors reported no changes of nasal resistances with altitude. 7 Furthermore, a significant increase in PNIF values has been observed when simulating the passage from the sea level to 8000 m in a hypobaric chamber.…”

“…In particular, high-altitude trips (defined as higher than 2700 m above sea level) 4 may cause nasal congestion, impaired nasal mucociliary transport rate, and increased nasal resistances due to decreased partial oxygen pressure and dry air. [5][6][7] Even though nasal cytology has been recognized as a useful diagnostic tool in rhinology for more than 100 years, only recently the interest in this field has increased. Nasal cytology is indeed relatively simple and very useful in clinical follow-up, 8,9 and in the last years, many authors have tried to investigate rhinopathies also from a cytological point of view.…”

The effect of high altitude on nasal nitric oxide levels

“…Exposure the cold air also increases nasal secretions, which leads to nasal blockage. All these factors also disturb the mucociliary transport mechanism and the physiology of paranasal sinuses [19][20][21][22]. however, as described above there was non-disturbing weather during the study and nnO measurements.…”

Chronic Exposure to High Altitude: Synaptic, Astroglial and Memory Changes

“…It is known that mice exposed to HA experienced significant initial weight loss and had a slower rate of weight gain compared to the weight gain of mice at SL 13 (present study, data not shown). This weight loss and slow gain could be explained by either increased or decreased whole body metabolic rate at HA or by the olfactory function impairment as reduced sniffing capacities 51,52 , which may be associated to the reduced synaptic protein expression and consequent neuronal dysfunction in the olfactory cortex neurons. Moreover synaptic changes in the olfactory cortex of CEHA animals can be associated with alterations in the release of acetylcholine, a crucial neurotransmitter for memory function 53 .…”