The Effect of Bright Light and LEET on Sleep after a 10-Hour Phase Delay.

Shift work and jet lag can cause circadian desynchronosis. Bright light and Low Energy Emission Therapy LEET, separately and together, were tested as interventions to improve sleep after a 10-hr phase delay of the workrest cycle. Both interventions decreased awakenings during the first daytime sleep period after the phase shift. After 3 nights of bright light administration from 2200-0200 each night, the subjects who received bright light had greater total sleep time, better sleep efficiency, and less wake time during the sleep period as compared to subjects who were exposed to dim light. Three days of LEET treatment for 20-min prior to each daytime sleep period showed a non-significant trend for similar additive benefits, with the group who received both bright light and LEET showing greater total sleep time than the group who received only light, and the group that received only LEET showing greater total sleep time than the control group who received neither intervention.