Effect of High Altitude Exposure, Acclimatization and Re-exposure on Nocturnal Breathing Pattern in Lowlanders

Effect of High Altitude Exposure, Acclimatization and Re-exposure on Nocturnal Breathing Pattern in Lowlanders

Effect of High Altitude Exposure, Acclimatization and Re-exposure on Nocturnal Breathing Pattern in Lowlanders

Prospective interventional trial in lowlanders evaluating the effect of acute exposure, acclimatization and re-exposure of high altitude on nocturnal breathing pattern.

Respiratory polygraphies will be performed in Santiago de Chile, 520 m, over the course of 3 days. Participants will then travel by commercial airline (5 h flight) and by bus (3 h ride) to the ALMA base camp located at 2900 m near San Pedro de Atacama, northern Chile. Participants will stay there for the next 7 nights and respiratory polygraphies will be performed on night 1 and 6. They will be spend the days (6-8 h daily) at the telescope station at 5050 m while undergoing physiological testing. Daily transports from 2900 to 5050 m will be by car (1 h ride, one way). After the first 8 day altitude sojourn participants will return to the Santiago area (520 m) for a 6 day recovery period. A second altitude sojourn with an identical schedule as the one described above and a final low altitude stay of 3 days will follow.

Acute high altitude exposure followed by 8 day acclimatization and re-exposure after 6 days at low altitude

Change in mean nocturnal oxygen saturation over the course of high altitude exposure during 2 sojourns at 5050 m compared to low altitude

first sojourn at 5050 m, night 1, 6; second sojourn at 5050 m, night 1, 6; low altitude sojourn at 520 m, night 1

Change in apnea-/hypopnea index over the course of high altitude exposure during 2 sojourns at 5050 m compared to low altitude

first sojourn at 5050 m, night 1, 6; second sojourn at 5050 m, night 1, 6; low altitude sojourn at 520 m, night 1

Change in oxygen desaturation index over the course of high altitude exposure during 2 sojourns at 5050 m compared to low altitude

first sojourn at 5050 m, night 1, 6; second sojourn at 5050 m, night 1, 6; low altitude sojourn at 520 m, night 1

Incidence of acute mountain sickness (AMSc score >= 0.7) over the course of high altitude exposure during 2 sojourns at 5050 m compared to low altitude

first sojourn at 5050 m, day 2, 7; second sojourn at 5050 m, day 2,7; low altitude sojourn at 520 m, day 2

Inclusion Criteria: born, raised and currently living <800m No overnight stay at altitudes >1500 m 4 weeks before the study Exclusion Criteria: Previous altitude intolerance to altitude <3000 m Pregnancy Health impairment, which requires regular treatment