[Effects of oxygen enrichment of room air on sleep patterns at high altitude].

OBJECTIVE: To explore how hypoxia circumstance affects sleep architecture and to study the potential use of oxygen enrichment of room air at an altitude of 3700 m. METHODS: Oxygen concentration was raised to (24.30 +/- 0.88)% in a room with a dimension of 4.51 m x 3.32 m x 3.41 m. Twelve men aged 18 to 20 years who had stayed at high altitude (3700 m above sea level) for 30 days slept one night in a room of ambient air and another night in the oxygen enriched room the order being randomized. Their electroencephalograms (EEG) were recorded with CFM-8 polysomnography. RESULTS: Significantly more time was spent in deep sleep (stages III and IV combined, also known as slow-wave sleep) with oxygen enriched than ambient air [(19.33 +/- 4.85)% vs (13.67 +/- 3.75)%, P < 0.01 with paired comparisons]. The total sleep time [(500.83 +/- 32.94) min vs (470.67 +/- 27.43) min, P < 0.05] and the efficient sleep index [(90.33 +/- 2.06)% vs (85.50 +/- 3.34)%, P < 0.001] were increased in oxygen enriched air. No differences between ambient and oxygen enriched air were found in sleep latency the time to fall asleep, the number of arousal and sleep shift (the time spent awake after falling asleep), but there was a trend toward fewer of these with oxygen treatment. CONCLUSIONS: Installing an oxygen-enriched room at high altitude is relatively simple and inexpensive, and there will be a promise for improving sleep quality, well-being, and work capacity.

[The effect of rhodiola and acetazolamide on the sleep architecture and blood oxygen saturation in men living at high altitude].

OBJECTIVE: To study the changes of sleep architecture and blood oxygen saturation (SaO(2)) during sleep in men living at high altitude, and to investigate the effect of rhodiola and acetazolamide on these sleep indexes. METHODS: Twenty-four men aged 18 to 21 years who had stayed at high altitude (5 380 m above sea level) for 1 year were randomly divided into groups A (treated with oral rhodiola), B (treated with oral acetazolamide) and C (treated with rhodiola + acetazolamide). Their sleep architecture and SaO(2) were recorded for 24 days before and after taking the medicines. RESULTS: Compared with baseline, the waking SaO(2) (WSaO(2)), the lowest SaO(2) (LSaO(2)) and the mean SaO(2) (MSaO(2)) were increased significantly after treatment for 24 days (P < 0.01), and the times of oxygen desaturation >/= 4% per hour (DI4) and the percentage of time spent at SaO(2) below 80% (SIT(80)) were decreased significantly (P < 0.01). After treatment, the NREM I and II was shortened, and III + IV and REM sleep were prolonged (P < 0.01): the total waking time (TWT) was shortened, and the sleep efficiency index (SEI) was markedly increased (P < 0.01). Compared with group A's, groups B's and C's SIT(80) were increased (P < 0.05). CONCLUSION: Both rhodiola and acetazolamide were effective in modulating the sleep architecture and improving the sleep quality in young men living at high altitude, but there was no synergistic effect between rhodiola and acetazolamide.