title: Sleep Architecture in Partially Acclimatized Lowlanders and Native Tibetans at 3800 Meter Altitude: What Are the Differences?
abstract: It is not well known whether high altitude acclimatization could help lowlanders improve their sleep architecture as well as Native Tibetans. In order to address this, we investigated the structural differences in sleep between Native Tibetans and partially acclimatized lowlanders and examined the association between sleep architecture and subjective sleep quality. Partially acclimatized soldiers from lowlands and Native Tibetan soldiers stationed at Shangri-La (3800 m) were surveyed using the Pittsburgh Sleep Quality Index (PSQI), Hamilton Anxiety Scale (HAMA), and Hamilton Depression Rating Scale (HAMD). The sleep architecture of those without anxiety (as determined by HAMA>14) and/or depression (HAMD>20) was analyzed using polysomnography and the results were compared between the two groups. One hundred sixty-five male soldiers, including 55 Native Tibetans, were included in the study. After partial acclimatization, lowlanders still exhibited differences in sleep architecture as compared to Native Tibetans, as indicated by a higher PSQI score (8.14±2.37 vs. 3.90±2.85, p<0.001), shorter non-rapid eye movement (non-REM) sleep (458.68±112.63 vs. 501±37.82 min, P=0.03), lower nocturnal arterial oxygen saturation (Spo2; mean 91.39±1.24 vs. 92.71±2.12%, p=0.03), and increased times of Spo2 reduction from 89% to 85% (median 48 vs.17, p=0.04) than Native Tibetans. Sleep onset latency (β=0.08, 95%CI: 0.01 to 0.15), non-REM latency (β=0.011, 95%CI 0.001 to 0.02), mean Spo2 (β=-0.79, 95%CI: -1.35 to -0.23) and time in stage 3+4 sleep (β=-0.014, 95%CI: -0.001 to -0.028) were slightly associated with the PSQI score. Partially acclimatized lowlanders experienced less time in non-REM sleep and had lower arterial oxygen saturation than Native Tibetans at an altitude of 3800 m. The main independent contributors to poor sleep quality are hypoxemia, difficulty in sleep induction, and time in deep sleep.
authors.affiliation: Department of Neurology, Kunming General Hospital of Chengdu Military Command , Kunming, Yunnan Province, People's Republic of China .
authors.forename: Fanyi
authors.initials: F
authors.lastname: Kong
authors.affiliation: Department of Neurology, Kunming General Hospital of Chengdu Military Command , Kunming, Yunnan Province, People's Republic of China .
authors.forename: Shixiang
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Neurology, Kunming General Hospital of Chengdu Military Command , Kunming, Yunnan Province, People's Republic of China .
authors.forename: Qiong
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Neurology, Kunming General Hospital of Chengdu Military Command , Kunming, Yunnan Province, People's Republic of China .
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000328:Adult; D000531:Altitude; D001007:Anxiety / Q000150:complications; D003863:Depression / Q000150:complications; D006801:Humans; D000860:Hypoxia; D008297:Male; D008889:Military Personnel; D010092:Oximetry; D010101:Oxygen Consumption; D017286:Polysomnography; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000209:etiology / Q000503:physiopathology*; D018609:Tibet; D055815:Young Adult
keywords: Tibetans; high altitude; lowerlander; polysomnography; sleep architecture