BACKGROUND There is conflict between living according to our endogenous biological rhythms and our external environment, with disruptions resulting in negative consequences to health and performance. This is often documented in shift work and jet lag, but 'societal norms' (eg, typical working hours) can create profound issues for 'night owls', people whose internal biological timing predisposes them to follow an unusually late sleep-wake cycle. Night owls have also been associated with health issues, mood disturbances, poorer performance and increased mortality rates. METHODS This study used a randomized control trial design aimed to shift the late timing of night owls to an earlier time (phase advance), using non-pharmacological, practical interventions in a real-world setting. These interventions targeted light exposure (through earlier wake up/sleep times), fixed meals times, caffeine intake and exercise. RESULTS Overall, participants demonstrated a significant advance of ∼2 h in sleep/wake timings as measured by actigraphy and circadian phase markers (dim light melatonin onset and peak time of the cortisol awakening response), whilst having no adverse effect on sleep duration. Notably, the phase advance was accompanied by significant improvements to self-reported depression and stress, as well as improved cognitive (reaction time) and physical (grip strength) performance measures during the typical 'suboptimal' morning hours. CONCLUSIONS Our findings propose a novel strategy for shifting clock timing towards a pattern that is more aligned to societal demands that could significantly improve elements of performance, mental health and sleep timing in the real world.

中文翻译：

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重置“夜猫子”的迟到时间对心理健康和表现有积极影响。

背景 根据我们的内源性生物节律生活和我们的外部环境之间存在冲突，中断会对健康和表现产生负面影响。这通常记录在轮班工作和时差中，但“社会规范”（例如，典型的工作时间）可能会给“夜猫子”带来深刻的问题，这些人的内部生物时间使他们倾向于遵循异常晚的睡眠-觉醒周期。夜猫子还与健康问题、情绪障碍、表现不佳和死亡率增加有关。方法 本研究采用随机对照试验设计，旨在将夜猫子的晚睡时间提前（阶段提前），在现实世界中使用非药物、实用的干预措施。这些干预措施针对光照（通过更早的起床/睡眠时间）、固定进餐时间、咖啡因摄入量和锻炼。结果 总体而言，根据活动描记法和昼夜节律相位标记（昏暗的褪黑激素开始和皮质醇觉醒反应的峰值时间）测量，参与者的睡眠/觉醒时间显着提高了约 2 小时，同时对睡眠持续时间没有不利影响。值得注意的是，阶段推进伴随着自我报告的抑郁和压力的显着改善，以及在典型的“次优”早晨时间的认知（反应时间）和身体（握力）表现措施的改善。