Naval Submarine Medical Research Laboratory Groton United States
Navy submariners must contend with rotating schedules of shift work 8 hour watches that are out of sync with the natural daynight cycle. As a result, they experience circadian misalignment and fatigue, which can lead to decreases in cognitive performance and health, and can result in dangerous or costly errors. One way to prevent or alleviate circadian misalignment is through the strategic management of light exposure. The present research effort will investigate whether the judicious scheduling of light exposure through the use of personal light treatment devices PLTDs can help submariners maintain behavioral and physiological alignment with their operational schedules. Active duty submariners will be provided with PLTDs blue-light goggles and blue-blocking glasses designed to use light exposure to entrain the bodys circadian rhythms. PLTDs will be worn at morning and night for the duration of a 15 day underway a control group will not wear PLTDs. Assessments of objective sleep actigraphy, circadian phase, cognitive performance, and self-report sleep and mood measures will be made at the beginning and end of the underway mission. Analyses will compare biochemical circadian phase, sleep, cognitive, and self-report measures between groups. Use of PLTDs is expected to ease the circadian misalignment associated with changing and intense watch schedules, resulting in increased quality-of-life for sailors and increased efficiency and safety for Navy vessels.