Misiunaite Ieva, Eastman Charmane I, Crowley Stephanie J
Biological Rhythms Research Laboratory, Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL, United States.
Front Neurosci. 2020 Feb 12;14:99. doi: 10.3389/fnins.2020.00099. eCollection 2020.
Many adolescents fall asleep too late to get enough sleep (8-10 h) on school nights. Morning bright light advances circadian rhythms and could help adolescents fall asleep earlier. Morning bright light treatment before school, however, is difficult to fit into their morning schedule; weekends are more feasible. We examined phase advances in response to morning light treatment delivered over one weekend. Thirty-seven adolescents (16 males; 14.7-18.0 years) who reported short school-night sleep (≤7 h) and late bedtimes (school-nights ≥23:00; weekend/non-school nights ≥24:00) slept as usual at home for ∼2 weeks ("baseline") and then kept a fixed sleep schedule (baseline school-night bed and wake-up times ±30 min) for ∼1 week before living in the lab for one weekend. Sleep behavior was measured with wrist actigraphy and sleep diary. On Saturday morning, we woke each participant 1 h after his/her midpoint of baseline weekend/non-school night sleep and 1 h earlier on Sunday. They remained in dim room light (∼20 lux) or received 1.5 or 2.5 h of intermittent morning bright light (∼6000 lux) on both mornings. The dim light melatonin onset (DLMO), a phase marker of the circadian timing system, was measured on Friday and Sunday evenings to compute the weekend circadian phase shift. The dim room light and 1.5-h bright light groups advanced the same amount (0.6 ± 0.4 and 0.6 ± 0.5 h). The 2.5-h bright light group advanced 1.0 ± 0.4 h, which was significantly more than the other groups. These data suggest that it is possible to phase advance the circadian clock of adolescents who have late bedtimes and short school-night sleep in one weekend using light that begins shortly after their sleep midpoint.
许多青少年在上学日的晚上入睡过晚，无法获得足够的睡眠（8 - 10小时）。早晨明亮的光线可使昼夜节律提前，有助于青少年更早入睡。然而，上学前进行早晨明亮光线治疗很难纳入他们的早晨日程安排；周末则更可行。我们研究了在一个周末进行早晨光线治疗后的相位提前情况。37名青少年（16名男性；年龄14.7 - 18.0岁）报告称上学日晚上睡眠时间短（≤7小时）且就寝时间晚（上学日晚上≥23:00；周末/非上学日晚上≥24:00），他们在家中照常睡眠约2周（“基线期”），然后在进入实验室度过一个周末之前，保持固定的睡眠时间表（基线期上学日晚上的就寝和起床时间±30分钟）约1周。使用腕部活动记录仪和睡眠日记来测量睡眠行为。在周六早晨，我们在每位参与者基线期周末/非上学日晚上睡眠中点之后1小时叫醒他们，周日则提前1小时叫醒。在这两个早晨，他们要么处于昏暗的室内光线（约20勒克斯）中，要么接受1.5或2.5小时的间歇性早晨明亮光线（约6000勒克斯）照射。在周五和周日晚上测量暗光褪黑素起始时间（DLMO），这是昼夜节律计时系统的一个相位标记，以计算周末的昼夜节律相位偏移。暗光组和1.5小时明亮光线组的相位提前量相同（分别为0.6±0.4小时和0.6±0.5小时）。2.5小时明亮光线组的相位提前了1.0±0.4小时，显著多于其他组。这些数据表明，对于就寝时间晚且上学日晚上睡眠时间短的青少年，在一个周末使用在他们睡眠中点后不久开始的光线照射，有可能使昼夜节律时钟提前。
