Submariner Performance with 24-hour Lighting

United States Navy submariners have historically lived with circadian disruption while at sea due to 18-h-based watchschedules. Previous research demonstrated that circadian entrainment improved with 24-h-based watchschedules. Twenty-nine male crew members participated in the study, which took place on an actual submarine patrol. The crew were exposed, first, to experimental high correlated color temperature fluorescent light sources and then to standard-issue fluorescent light sources. A variety of outcome measures were employed to determine if higher levels of circadian-effective light during on-watch times would further promote behavioral alignment to 24-h-based watchschedules.