In humans, circadian rhythms have an average period of 24.2 hours. The 24-hour patterns of light and dark on the retina synchronise circadian rhythms to the local time on earth. Lack of synchronisation between the endogenous clock and the local time has been associated with a host of maladies. Therefore, it is important to measure circadian light exposures over the course of the 24-hour day and to be able to assess circadian entrainment and disruption in actual living environments. Presented is an overview of the recently developed Daysimeter, a personal measurement device for recording activity and circadian light exposure. When the Daysimeter is worn on the head, two light sensors near the eye are used to estimate circadian light exposures over extended periods of time. Phasor analysis combines the measured periodic activity-rest patterns with the measured periodic light—dark patterns to assess behavioural circadian entrainment/disruption. As shown, day-shift and rotating-shift nurses exhibit remarkably different levels of behavioural circadian entrainment/disruption. These new ecological measurement and analysis techniques may provide important insights into the relationship between circadian disruption and well-being.

中文翻译：

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光照、活动和昼夜节律紊乱的生态测量

在人类中，昼夜节律的平均周期为 24.2 小时。视网膜上 24 小时的明暗模式使昼夜节律与地球上的当地时间同步。内源性时钟与当地时间之间缺乏同步与许多疾病有关。因此，重要的是在一天 24 小时内测量昼夜节律光照并能够评估实际生活环境中的昼夜节律夹带和中断。介绍了最近开发的 Daysimeter 的概述，这是一种用于记录活动和昼夜节律曝光的个人测量设备。当 Daysimeter 戴在头上时，眼睛附近的两个光传感器用于估计长时间暴露的昼夜节律。相量分析将测量的周期性活动-休息模式与测量的周期性明暗模式相结合，以评估行为昼夜节律夹带/中断。如图所示，白班和轮班护士表现出明显不同的行为昼夜节律夹带/干扰水平。这些新的生态测量和分析技术可能为了解昼夜节律紊乱与福祉之间的关系提供重要见解。