Sleep patterns during 20-m nitrox saturation dives.

The sleep patterns were examined through three simulated 20-m nitrox saturation dives. The standard polysomnography of 12 divers was recorded respectively for a total of 204 nights, as were patterns of change or consistency in sleep variables. For the 11 divers in their 20s and 30s there was nothing unusual about their sleep variables. However, a reduction of total sleep time in accordance with the lengthening of sleep latency was observed. This was recognized from the latter part of the bottom period to the postdive period. This tendency was notable for the diver in his 50s. These findings suggest that the decompression environment and the psychological stress of the long-term closed environment of a hyperbaric chamber have effects on divers' sleep.