REGULATION OF HUMAN BIOLOGY BY CHANGES IN DAYLENGTH

大多数生物在生长的过程中都会表现出明显的季节变化。 当年 在许多情况下，这种变化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 通常以两种方式影响动物。 第一，不断的日膨胀 或光周期的收缩可以引起动物的日常活动， 休息阶段扩大或收缩，使其与光周期相匹配。 其次，光周期的特定变化可以引发新的行为，例如 如冬眠、迁徙或繁殖， 在特定的季节里普遍存在的情况。 这些新行为 通常伴随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，光周期控制生物体 通过它对生物钟机制的影响， 独立的昼夜节律振荡器来跟踪不断变化的时间， 一年中的黎明和黄昏 该项目旨在研究人类生物学是否与 受光周期变化的控制。 我们每天监测 睡眠模式，激素和体温在个人生活 一个月的时间表上的光暴露，模拟自然的， 冬日 它们在环境自然光和人造光下自由活动 每天十个小时，但被关在一个黑暗的房间里十四个小时 每天晚上。 为了进行比较，我们在同一个实验室中进行了类似的测量。 个人，而他们生活了一个星期的传统时间表， 它们每天暴露在环境光下16个小时， 每晚在黑暗的房间里睡八个小时。 实验结果表明，人类的昼夜节律系统是 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：夜晚之后， 人工延长到14小时，睡眠分为两部分 逐渐分开 夜间成分（E）与 皮质醇分泌的每日偏移，褪黑激素分泌的开始， 催乳素分泌、睡眠开始、慢波睡眠高峰和下降 体温升高，一直持续到黄昏 早上的部分 (M)与皮质醇分泌的每日发作相关， 褪黑激素分泌，催乳素分泌抵消，快速眼动睡眠高峰，上升 在体温和觉醒的开始，它被带到黎明。 这一结果可能对人类生物学产生重要影响， 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 day length, 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 prolactin 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, offset of prolactin 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.