Citation

Seo Yj, Matsumoto K, Park YM, Mohri M, Matsuoka S. Int. J. Ind. Ergonomics 2001; 28(3-4): 203-218.

Copyright

(Copyright © 2001, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The purpose of this study is to examine sleep structure under the hyperbaric environment to obtain fundamental data so that a desirable sleep environment for divers may be organized using the polysomnography. Using standard polysomnography, the total sleep time (TST), sleep efficiency index (SEI), number of awakenings (No A), lengthening of stage 1 sleep (LS1S), and lengthening of stage 4 sleep (LS4S) for 12 divers were measured over a period of 268 nights in three simulated conditions under a hyperbaric saturation environment of a He-O2 mixture at a depth equivalent to 16, 19, and 24 ATA. In the three diving conditions during the bottom nights and during the decompression nights (at 16, 19, and 24 ATA), the statistically significant results were shown: a reduction of TST, a decrease of SEI, an increase of No A after sleep or from rapid eye movements (REM) sleep, a LS1S deviation, and a reduction of LS4S deviation. The amount of LS4S was largest in the 16 ATA diving condition on the bottom nights and the decompression nights, and tended to decrease in order of 19 and 24 ATA diving conditions. The No A from REM sleep and interruption of REM sleep were significantly higher on the bottom nights and decompression nights than predive nights, and tended remarkably to increase in the order of 16-24 ATA on decompression nights. The sleep patterns under the three saturation diving conditions showed disorders in the bottom nights and decompression nights. However, these disorders continually worsened with increasing depth from 16 to 24 ATA. The psychological stress in the divers that gives rise to sleep disorders is caused by compression and decompression and from long periods of stay under closed conditions.