The influence of intensity and timing of daily light exposure on subjective and objective sleep in adolescents with an evening circadian preference.

The aim of the present study is to examine the relationship between light and sleep, in adolescents with an evening circadian preference. For a period of seven days, ninety-nine adolescents wore a wrist actigraph to assess light exposure and objective sleep and completed a sleep diary to assess subjective sleep. Lower average light intensity across the preceding 24 hours was associated with a later sleep onset (p<.01) and a later next-day sleep offset (p<.05). A later time of last exposure to more than 10 lux was associated with a later sleep onset (p<.001) and a shorter objective total sleep time (p<.001), as well as a later bedtime (p<.001) and a shorter subjective total sleep time (p<.001). Furthermore, exploratory analyses found that lower average early morning light exposure (between 4–9AM) was associated with later sleep onset (p<.05), a later next-day sleep offset (p<.05), and a later next-day waketime, (p<.01), lower average afternoon light exposure (between 2–7PM) was associated with an later next-day sleep offset (p<.05), and lower average evening light exposure (between 7PM-12AM) was associated with longer subjective total sleep time (p<.001). This study highlights the importance of light exposure, particularly the timing of light exposure, for establishing healthy patterns of sleep among adolescents with a propensity for a delayed bedtime and waketime. These findings provide additional evidence for targeting light exposure when designing interventions to improve adolescent sleep.

本研究的目的是探究具有晚睡昼夜节律偏好的青少年的光照与睡眠之间的关系。 在为期七天的时间里，九十九名青少年佩戴了手腕活动记录仪以评估光照暴露情况和客观睡眠，并完成一份睡眠日记以评估主观睡眠。 过去24小时内平均光照强度较低与入睡时间较晚（p<0.01）以及次日醒来时间较晚（p<0.05）有关。最后一次暴露于10勒克斯以上光照的时间较晚与入睡时间较晚（p<0.001）、客观总睡眠时间较短（p<0.001）以及上床睡觉时间较晚（p<0.001）和主观总睡眠时间较短（p<0.001）有关。此外，探索性分析发现，清晨（4 - 9点之间）平均光照暴露较低与入睡时间较晚（p<0.05）、次日醒来时间较晚（p<0.05）以及次日起床时间较晚（p<0.01）有关，下午（2 - 7点之间）平均光照暴露较低与次日醒来时间较晚（p<0.05）有关，傍晚（7点 - 12点之间）平均光照暴露较低与主观总睡眠时间较长（p<0.001）有关。 这项研究强调了光照暴露，特别是光照暴露的时间，对于在有晚睡晚起倾向的青少年中建立健康睡眠模式的重要性。这些发现为在设计改善青少年睡眠的干预措施时针对光照暴露提供了额外的证据。