title: Psychophysiologic changes in sleep during simulated 200-m heliox saturation dives.
abstract: The standard polysomnogram and questionnaire were measured from 4 subjects during 2 simulated 200-m heliox saturation dives. These measurements were performed for 1 precompression night, bottom nights, 4 or 5 nights during decompression, and 1 postdecompression night. Although the subjects reported a marked decrease in quantity and quality of sleep at the bottom, only a slight degree of sleep disturbance caused by frequent awakenings was found in polysomnograms. Throughout the dive period, latency of each sleep stage, quantity of REM sleep, and the REM-NREM cycle showed no changes, whereas quantity of slow wave sleep remained at a low level. From these results it was inferred that basic sleep mechanisms were not affected under 200-m heliox environment. Unusual physiologic phenomena were observed during the dive period. Intermittent diffuse rhythmic theta activity was found in 1 subject at sleep stage REM during the bottom. Rhythmic contraction of facial muscles, which was similar to bruxism, increased, particularly at sleep stage 2 in all subjects during decompression.
authors.affiliation: Undersea Medical Center, Japan Maritime Self-Defense Force, Kanagawa.
authors.forename: K
authors.initials: K
authors.lastname: Ozawa
authors.forename: A
authors.initials: A
authors.lastname: Hashimoto
authors.forename: H
authors.initials: H
authors.lastname: Oiwa
mesh_terms: D000328:Adult; D003664:Decompression; D004242:Diving; D006371:Helium; D006801:Humans; D008297:Male; D010100:Oxygen; D012890:Sleep / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology
chemical_list: D006371:Helium; C038949:heliox; D010100:Oxygen