How to shift the human sleep-wake eycle: a simulation study incorporating monochromatic blue light

摘要

A sleep-wake cycle (SWC) forced by shift work often dissociates with physiological rhythms. It is therefore desirable to shift human SWC. We propose a model which outputs time of sleep onset and wake up and allows to adapt SWC due to the influence of ambient light. Several model parameters were optimized utilizing Genetic Algorithms to account for chronotypes, i. e. individual differences in timing of sleep habits. Monochromatic blue light has much stronger circadian effects than polychromatic white light. Therefore portable blue-light sources should be utilized to shift the individual SWC effectively. Our model is able to simulate both sleep homeostasis and circadian phase shifts under real light influences and shift work schedules. We show that adaptation to a 4-week night shift (of a chronotype who never worked night shifts before) results in severe sleep deprivations. Selective application of 400 lux of monochromatic blue light leads to an increased phase shift and a reduction of drowsiness during working by 32.8%.