Figueiro Mariana G, Rea Mark S
Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
Neuro Endocrinol Lett. 2010;31(1):92-6.
Circadian timing affects sleep onset. Delayed sleep onset can reduce sleep duration in adolescents required to awake early for a fixed school schedule. The absence of short-wavelength ("blue") morning light, which helps entrain the circadian system, can hypothetically delay sleep onset and decrease sleep duration in adolescents. The goal of this study was to investigate whether removal of short-wavelength light during the morning hours delayed the onset of melatonin in young adults.
Dim light melatonin onset (DLMO) was measured in eleven 8th-grade students before and after wearing orange glasses, which removed short-wavelength light, for a five-day school week.
DLMO was significantly delayed (30 minutes) after the five-day intervention, demonstrating that short-wavelength light exposure during the day can be important for advancing circadian rhythms in students.
Lack of short-wavelength light in the morning has been shown to delay the circadian clock in controlled laboratory conditions. The results presented here are the first to show, outside laboratory conditions, that removal of short-wavelength light in the morning hours can delay DLMO in 8th-grade students. These field data, consistent with results from controlled laboratory studies, are directly relevant to lighting practice in schools.
昼夜节律影响入睡时间。入睡时间延迟会缩短青少年的睡眠时间，因为他们需要按照固定的学校作息时间表早起。短波长（“蓝光”）的早晨光线有助于调节昼夜节律系统，理论上，缺乏这种光线可能会延迟青少年的入睡时间并缩短睡眠时间。本研究的目的是调查在早晨时段去除短波长光线是否会延迟年轻人褪黑素的分泌起始时间。
在11名八年级学生佩戴橙色眼镜（可去除短波长光线）前后，测量他们的暗光褪黑素分泌起始时间（DLMO），佩戴时间为一个为期五天的上学周。
为期五天的干预后，DLMO显著延迟了30分钟，表明白天暴露于短波长光线下对于促进学生的昼夜节律很重要。
在受控实验室条件下，已证明早晨缺乏短波长光线会延迟生物钟。此处呈现的结果首次表明，在实验室以外的条件下，早晨去除短波长光线会延迟八年级学生的DLMO。这些现场数据与受控实验室研究的结果一致，与学校的照明实践直接相关。
