Key to the transition of humans from nomadic hunting‐gathering groups to industrialized and highly urbanized societies was the creation of protected and artificially lit environments that extended the natural daylight hours and consolidated sleep away from nocturnal threats. These conditions isolated humans from the natural regulators of sleep and exposed them to higher levels of light during the evening, which are associated with a later sleep onset. Here, we investigated the extent to which this delayed timing of sleep is due to a delayed circadian system. We studied two communities of Toba/Qom in the northern region of Argentina, one with and the other without access to electricity. These communities have recently transitioned from a hunting‐gathering subsistence to mixed subsistence systems and represent a unique model in which to study the potential effects of the access to artificial light on sleep physiology. We have previously shown that participants in the community with access to electricity had, compared to participants in the community without electricity, later sleep onsets, and shorter sleep bouts. Here, we show they also have a delayed dim‐light melatonin onset (DLMO). This difference is present during the winter but not during the spring when the influence of evening artificial light is likely less relevant. Our results support the notion that the human transition into artificially lit environments had a major impact on physiological systems that regulate sleep timing, including the phase of the master circadian clock.

中文翻译：

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在传统的狩猎采集者 Toba/Qom 社区中，使用电灯与昏暗的褪黑激素发生延迟有关。

人类从游牧狩猎采集群体过渡到工业化和高度城市化社会的关键是创造受保护的人工照明环境，延长自然光照时间并巩固睡眠，远离夜间威胁。这些条件将人类与睡眠的自然调节器隔离开来，并在晚上将他们暴露在更高水平的光线下，这与较晚的睡眠时间有关。在这里，我们调查了这种延迟睡眠时间在多大程度上是由于昼夜节律系统延迟造成的。我们研究了阿根廷北部地区多巴/库姆的两个社区，一个有电，另一个没有电。这些社区最近已从狩猎采集生计过渡到混合生计系统，并代表了一种独特的模型，可以在其中研究获得人造光对睡眠生理学的潜在影响。我们之前已经表明，与没有电的社区参与者相比，有电社区的参与者睡眠时间更晚，睡眠时间更短。在这里，我们展示了它们也具有延迟的昏暗褪黑激素发作 (DLMO)。这种差异存在于冬季，但不存在于春季，因为夜间人造光的影响可能不太相关。我们的结果支持这样一种观点，即人类过渡到人工照明环境对调节睡眠时间的生理系统产生了重大影响，