Faculty of Design, Kyushu University, Fukuoka, Japan.
J Physiol Anthropol. 2011;30(3):97-102. doi: 10.2114/jpa2.30.97.
The present study evaluated the effects of exposure to light intensity in the morning on dim light melatonin onset (DLMO). The tested light intensities were 750 lux, 150 lux, 3000 lux, 6000 lux and 12,000 lux (horizontal illuminance at cornea), using commercial 5000 K fluorescent lamps. Eleven healthy males aged 21-31 participated in 2-day experiments for each light condition. On the first experimental day (day 1), subjects were exposed to dim light (<30 lux) for 3 h in the morning (09:00-12:00). On the same day, saliva samples were taken in dim light (<30 lux) every 30 min from 21:00 to 01:00 to determine the DLMO phase. The subjects were allowed to sleep from 01:00 to 08:00. On the second experimental day (day 2), the subjects were exposed to experimental light conditions for 3 h in the morning. The experimental schedule after light exposure was the same as on day 1. On comparing day 2 with day 1, significant phase advances of DLMO were obtained at 3000 lux, 6000 lux and 12,000 lux. These findings indicate that exposure to a necessary intensity from an ordinary light source, such as a fluorescent lamp, in the morning within one day affects melatonin secretion.
本研究评估了早晨光照强度对褪黑素分泌起始时间（DLMO）的影响。使用商业用 5000K 荧光灯，测试的光照强度分别为 750 勒克斯、150 勒克斯、3000 勒克斯、6000 勒克斯和 12000 勒克斯（角膜水平照度）。11 名年龄在 21-31 岁的健康男性分别参加了每种光照条件下的 2 天实验。在第一个实验日（第 1 天），受试者在早晨（09:00-12:00）接受 3 小时的暗光（<30 勒克斯）照射。当天，在暗光（<30 勒克斯）下，每隔 30 分钟从 21:00 到 01:00 采集唾液样本，以确定 DLMO 相位。受试者从 01:00 到 08:00 允许睡觉。在第二个实验日（第 2 天），受试者在早晨接受 3 小时的实验光照条件照射。光照暴露后的实验安排与第 1 天相同。与第 1 天相比，在 3000 勒克斯、6000 勒克斯和 12000 勒克斯时，DLMO 的相位明显提前。这些发现表明，在一天内早晨从普通光源（如荧光灯）接受必要的光照强度会影响褪黑素的分泌。
