Effects of zolpidem and zaleplon on sleep, respiratory patterns and performance at a simulated altitude of 4,000 m

The effects of zolpidem or zaleplon on sleep architecture, respiratory patterns and performance were assessed at a simulated altitude of 4,000 m. Twelve male healthy subjects spent 4 nights in a decompression chamber, 1 at sea level ( baseline), 3 at 4,000 m to test zolpidem ( 10 mg), zaleplon ( 10 mg) and placebo, given 15 min before switching the lights off. Sleep and respiratory patterns were analysed using polysomnography. Cognitive and physical performance was examined the next morning at sea level conditions. The study demonstrates that both zolpidem and zaleplon improved slow wave sleep at altitude, with zolpidem showing more marked effects than zaleplon. Both agents did not adversely affect respiration at altitude during the night, or cognitive or physical performance the next morning at the dosages used in this study. Thus, climbers may safely use both hypnotic agents. Copyright (C) 2004 S. Karger AG, Basel.