REGULATION OF HUMAN BIOLOGY BY CHANGES IN DAYLENGTH

在这个过程中，大多数生物都表现出惊人的季节性变化 这一年。在许多情况下，这种变化已知是由季节性因素引起的 日长或光周期的变化。光周期的变化一般 对动物有两方面的影响。首先，不断的日常扩张或 光周期的收缩会导致动物的日常活动或休息 相位扩张或收缩，使其与光周期相匹配。第二, 光周期的特定变化会引发新的行为，例如 冬眠、迁徙或繁殖，代表对 在特定季节盛行的条件。这些新行为是 通常伴随着并依赖于生物化学的显著变化， 生物体的生理学和解剖学。 基础研究人员提出，光周期控制着生物体 通过它对生物钟机制的影响，生物钟机制使用两个 独立的昼夜节律振荡器，以跟踪持续变化的时间 一年中有黎明，也有黄昏。 这个项目的目的是研究人类生物学是否与 受光周期变化的控制。我们监测日常生活模式 为一个人而活的人的睡眠、激素和体温的变化 在模拟自然冬日的日光照射时间表上的一个月。 它们在周围的自然光和人造光中自由活动了十年 每天几个小时，但每人被限制在黑暗的房间里14个小时 晚上好。为了进行比较，我们在相同的个体中进行了类似的测量 当他们按照传统的时间表生活一周时，他们 每天暴露在环境光下16个小时，睡在黑暗中 每晚有八个小时的房间。 实验结果表明，人类的昼夜节律系统 与其他动物相似--它由两个子系统组成， 其中一个与黎明同步，另一个与黄昏同步。这 结论是基于以下观察：夜幕降临后 人工延长至14小时，睡眠分为两部分 这种关系逐渐分道扬镳。晚间成分(E)与 每日皮质醇分泌失调，褪黑素分泌开始，开始 睡眠，慢波睡眠的高峰和体温下降，它 被缠绕到黄昏。早晨成分(M)与 每日皮质醇分泌开始，褪黑素分泌抵消，峰值 快速眼动睡眠，体温升高和开始清醒，这是 一直缠绕到黎明。 这一结果可能会对人类生物学和 医药。

Most living things exhibit striking seasonal changes during the course of the year. In many cases, the changes are known to be induced by seasonal changes in daylength, or photoperiod. Changes in the photoperiod generally affect animals in two ways. First, the constant daily expansion or contraction of the photoperiod can cause an animal's daily activity or rest phase to expand or contract, so that it matches the photoperiod. Second, specific changes in the photoperiod can trigger new behaviors, such as hibernation, migration, or breeding, that represent adaptations to conditions that prevail during a particular season. These new behaviors are often accompanied by and depend on marked changes in the biochemistry, physiology and anatomy of the organism. Basic researchers have proposed that the photoperiod controls the organism through its effects on a biological clock mechanism that employs two separate circadian oscillators to track the constantly changing times of dawn and dusk through the course of the year. This project is designed to investigate whether human biology is similarly subject to control by changes in the photoperiod. We monitor daily patterns of sleep, hormones and body temperature in individuals who live for one month on a schedule of light exposures that simulate a natural winter day. They move about freely in ambient natural and artificial light for ten hours each day but are confined to a dark room for fourteen hours each night. For comparison, we make similar measurements in the same individuals while they live for one week on a conventional schedule in which they are exposed to ambient light for sixteen hours each day and sleep in a dark room for eight hours each night. The results of the experiment suggest that the human circadian system is similar to that of other animals-that it is composed of two subsystems, one of which is synchronized with dawn and the other with dusk. This conclusion is based on the following observations: After night was artificially expanded to fourteen hours, sleep divided into two components that gradually moved apart. The evening component (E) was associated with the daily offset of cortisol secretion, onset of melatonin secretion, onset of sleep, peak of slow wave sleep and decline in body temperature, and it was entrained to dusk. The morning component (M) was associated with the daily onset of cortisol secretion, offset of melatonin secretion, peak of REM sleep, rise in body temperature and onset of wakefulness, and it was entrained to dawn. The results are likely to have important implications for human biology and medicine.