Sleep architecture, periodic breathing and mood disturbance of expeditioners at Kunlun Station (4087 m) in Antarctica
XU Chengli1,2*, LIU Shiying1, KONG Zhanping3 & CHEN Nan1
1. Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China;
2. Center of Environmental and Health Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China;
3. Qinghai Provincial People’s Hospital, Xining, Qinghai, China
Corresponding author, E-mail: email@example.com
Abstract: Several studies have reported the detrimental impacts of hypoxia exposure to sleep. Chinese Kunlun Station (altitude 4087 m) is located at Dome A, the highest point on the Antarctic ice sheet, one of the most extreme environments on Earth. This study investigated alteration of sleep, breathing and mood status in healthy expeditioners at Kunlun Station at Dome A. The study was conducted among 10 male volunteers of the inland transverse party to Kunlun Station during the 31st Chinese National Antarctic Research Expedition, and valid data from 8 volunteers were finally analyzed. Sleep structure, breathing pattern and mood were monitored by using portable polysomnography (PSG) equipment and profile of mood state (POMS) at two time points: (1) at Zhongshan Station (10 m) before departure to Kunlun Station; (2) on the 12 th–13th nights during the residence at Kunlun Station.
“Slow-wave sleep” (Stage 3 NREM) markedly reduced at Kunlun Station (P<0.01). Total sleep time, sleep efficiency and sleep latency showed no significant changes. Total respiratory events (P<0.05), apnea/hypopnea index (AHI) (P<0.05) and hyponea index (P<0.01) substantially increased at Kunlun Station. The most common type of respiratory disorder was periodic breathing occurring almost exclusively during non-rapid eye movement sleep. The oxygen desaturation index increased markedly (P<0.05), while nocturnal oxygen saturation dramatically fell at Kunlun Station (P<0.05). The score of vigor also decreased at Kunlun Station (P<0.05). Expeditioners experienced reduced slow wave sleep, induced periodic breathing, decreased oxygen saturation and decreased vigor at Kunlun Station.
Keywords: sleep, periodic breathing, expeditioner, Kunlun Station, Antarctica