GROTON, Conn.
Our bodies respond to daily light-dark cycles to maintain our circadian rhythms: our internal clocks that tell us we should be awake during the day and asleep at night. Researchers at the Naval Submarine Medical Research Laboratory (NSMRL) are investigating ways to maintain those rhythms in submariners, who cannot rely on natural sunlight or external environmental cues to stay on track.
When we wake up, when we go to sleep, when we are hungry, when we fall into a daily afternoon slumpâ¦all these processes are regulated by our circadian rhythms (also called circadian clocks). Sometimes, these rhythms fall out of sync with our actual lifestyles; think of the feeling of being jet lagged after travelling across several time zones. Jet lag is typically a short term problem that can be reset within a day or two. For Sailors going underway on submarines, maintaining or resetting their circadian rhythms can be far more difficult. Without being able to respond to the sun rising or setting and crews working around the clock to sustain 24-hour operations, submariners can fall into circadian misalignmentâthis means that they may have trouble falling asleep or waking up. Both loss of sleep and misalignment of the circadian clock can result in decreases in performance, increases in impulsivity, and even have health consequences. On submarines, any decrease in performance can lead to dangerous and costly errors.