Changes in sleep patterns during simulated nitrox saturation diving to 20 and 30 meters

Area of Science:

• Physiology
• Sleep Science
• Diving Medicine

Background:

• Saturation diving environments, utilizing nitrogen-oxygen (N2-O2) gas mixtures, are crucial for extended underwater operations.
• Understanding the physiological and psychological impacts of these environments on divers is essential for safety and performance.
• Nocturnal sleep quality is a critical factor in diver well-being and operational effectiveness.

Purpose of the Study:

• To evaluate the effects of a nitrogen-oxygen (N2-O2) saturation diving environment on nocturnal sleep patterns.
• To investigate potential differences in sleep quality related to varying dive depths (20m and 30m).
• To assess subjective feelings of fatigue in divers exposed to saturation conditions.

Main Methods:

• Conducted a study over 459 nights involving 27 divers in a simulated N2-O2 saturation diving environment.
• Monitored standard polysomnography and heart rate.
• Collected subjective fatigue ratings from divers at 20- and 30-meter equivalent depths.

Main Results:

• Observed prolonged sleep latency, reduced total sleep time, and decreased sleep efficiency index.
• Reported increased feelings of fatigue from the bottom period through post-dive.
• Noted an increase in awakenings, including from REM sleep, during bottom and decompression phases, slightly higher at 30m.
• Found no significant difference in sleep impact between 20m and 30m depths.

Conclusions:

• Prolonged confinement and reduced physical activity in saturation environments likely contribute to sleep deterioration.
• Sleep disturbances were evident during and after saturation dives, with no observed recovery post-dive.
• Dive depth (20m vs. 30m) did not appear to be a significant factor in the observed sleep impairments.