Arguelles-Prieto Raquel, Madrid Juan Antonio, Rol Maria Angeles, Bonmatí-Carrión María Ángeles
Chronobiology Lab, Department of Physiology, Faculty of Biology, Mare Nostrum Campus, University of Murcia, IUIE, IMIB-Arrixaca, 30100 Murcia, Spain.
Ciber Fragilidad y Envejecimiento Saludable (CIBERFES), 28029 Madrid, Spain.
Biology (Basel). 2022 Oct 28;11(11):1584. doi: 10.3390/biology11111584.
Several studies have investigated the relationship between daylight saving time (DST) and sleep alterations, psychiatric disorders, cardiovascular events and traffic accidents. However, very few have monitored participants while maintaining their usual lifestyle before and after DST. Considering that DST transitions modify human behavior and, therefore, people's light exposure patterns, the aim of this study was to investigate the potential effects of DST on circadian variables, considering sleep and, for the first time, the human phase response curve to light. To accomplish this, eight healthy adults (33 ± 11 years old, mean ± SD) were recruited to monitor multivariable circadian markers and light exposure by means of a wearable ambulatory monitoring device: Kronowise. The following night phase markers were calculated: midpoints of the five consecutive hours of maximum wrist temperature (TM5) and the five consecutive hours of minimum time in movement (TL5), sleep onset and offset, as well as sleep duration and light intensity. TM5 for wrist temperature was set as circadian time 0 h, and the balance between advances and delays considering the phase response curve to light was calculated individually before and after both DST transitions. To assess internal desynchronization, the possible shift in TM5 for wrist temperature and TL5 for time in movement were compared. Our results indicate that the transition to DST seems to force the circadian system to produce a phase advance to adapt to the new time. However, the synchronizing signals provided by natural and personal light exposure are not in line with such an advance, which results in internal desynchronization and the need for longer synchronization times. On the contrary, the transition back to ST, which implies a phase delay, is characterized by a faster adaptation and maintenance of internal synchronization, despite the fact that exposure to natural light would favor a phase advance. Considering the pilot nature of this study, further research is needed with higher sample sizes.
多项研究调查了夏令时（DST）与睡眠改变、精神疾病、心血管事件和交通事故之间的关系。然而，很少有研究在夏令时前后维持参与者的日常作息方式的同时对其进行监测。考虑到夏令时的转换会改变人类行为，进而改变人们的光照模式，本研究的目的是调查夏令时对昼夜节律变量的潜在影响，同时考虑睡眠情况，并且首次研究人类对光的相位反应曲线。为实现这一目标，招募了8名健康成年人（33±11岁，均值±标准差），通过可穿戴式动态监测设备Kronowise来监测多变量昼夜节律指标和光照情况。计算了以下夜间相位指标：连续五个小时手腕温度最高值的中点（TM5）、连续五个小时活动时间最短值的中点（TL5）、入睡和起床时间，以及睡眠时间和光照强度。将手腕温度的TM5设定为昼夜时间0时，并分别计算了两次夏令时转换前后考虑到对光的相位反应曲线的提前和延迟之间的平衡。为评估内部不同步情况，比较了手腕温度的TM5和活动时间的TL5可能出现的偏移。我们的结果表明，向夏令时的转换似乎迫使昼夜节律系统产生一个相位提前以适应新时间。然而，自然和个人光照提供的同步信号与这种提前不一致，这导致了内部不同步以及需要更长的同步时间。相反，恢复到标准时间（ST）的转换意味着相位延迟，其特点是尽管自然光照射有利于相位提前，但内部同步的适应和维持速度更快。考虑到本研究的探索性质，需要进行更大样本量的进一步研究。
