ABSTRACT
Sleep at high altitude is characterized by poor subjective quality, increased awakenings,
frequent brief arousals, marked nocturnal hypoxemia, and periodic breathing. A change
in sleep architecture with an increase in light sleep and decreasing slow-wave and
REM sleep have been demonstrated. Periodic breathing with central apnea is almost
universally seen amongst sojourners to high altitude, although it is far less common
in long-standing high altitude dwellers. Hypobaric hypoxia in concert with periodic
breathing appears to be the principal cause of sleep disruption at altitude. Increased
sleep fragmentation accounts for the poor sleep quality and may account for some of
the worsened daytime performance at high altitude. Hypoxic sleep disruption contributes
to the symptoms of acute mountain sickness. Hypoxemia at high altitude is most severe
during sleep. Acetazolamide improves sleep, AMS symptoms, and hypoxemia at high altitude.
Low doses of a short acting benzodiazepine (temazepam) may also be useful in improving
sleep in high altitude.
KEYWORD
sleep - high altitude - periodic breathing - hypoxemia - sleep fragmentation - hyopbaric
hypoxia
