0686 OPTIMIZATION OF LIGHT INTERVENTION TO TREAT CIRCADIAN MISALIGNMENT

Abstract

Circadian misalignment, as observed during jetlag and shiftwork, leads to increased fatigue, risk of accidents and disease. A number of studies demonstrated that re-entrainment can be accelerated by bright light intervention, applied according to the phase-response curve. However, no standardized guidelines regarding the duration, intensity or timing of light exposure to optimize re-entrainment have been established. Mathematical models have been used before to investigate optimal light exposure and facilitate adaptation. However, they predicted one optimal lighting solution for each phase difference, which makes them difficult to apply in practice due to differences in individuals’ social and physiological constraints. We use arousal dynamics model comprising the neurobiological, sleep-wake switch model of Phillips and Robinson and the dynamic circadian oscillator model by Kronauer et al. to investigate optimal light schedules for adaptation to circadian misalignment. Using the model we build a 3-dimensional phase-response surface, which allows us to determine optimal light schedules and can be verified experimentally. The model predicts multiple light exposure solutions leading to an optimized duration of adaptation. The solutions for the same phase shift are diverse, ranging from short bright light exposure of 2–3 hours per day to prolonged exposure of more than 10 hours per day. Our study thus allows customization of light exposure schedules to treat circadian misalignment depending on individual social and physiological constraints without increasing adaptation times. This work was supported by the Australian Research Council Center of Excellence for Integrative Brain Function (ARC Center of Excellence Grant CE140100007), the Australian Research Council Laureate Fellowship Grant (FL140100025).