A recent elegant study published in this journal (Zerbini, Winnebeck & Merrow, J Pineal Res, e12723, 2021) reported data on weekly and seasonal changes in circadian timing, as assessed by the melatonin rhythm in dim light in a population that was exposed to a change from standard time to day light saving time. The authors highlight a one hour earlier timing of melatonin onset in summer compared with winter and a 20 minutes delay on work-free days compared with work days. The variations in the timing of the melatonin rhythm are reported in standard time and the authors imply that the data are consistent with synchronization to midday and that “we know that humans entrain to sun time.” Here, we show that their extensive data are most parsimoniously explained by entrainment to local clock time and associated light exposure rather than “sun time,” indexed by either dawn or midday.

中文翻译：

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人体褪黑激素昼夜节律的每周和季节性变化：是否受当地时钟时间、社交时间、光照或太阳时间的影响？

最近发表在该期刊上的一项优雅研究 ( Zerbini, Winnebeck & Merrow, J Pineal Res, e12723, 2021) 报告了关于昼夜节律时间的每周和季节性变化的数据，这是通过暴露于标准时间到夏令时变化的人群中昏暗光线下的褪黑激素节律评估的。作者强调，与冬季相比，夏季褪黑激素的作用时间提前 1 小时，以及与工作日相比，无工作日延迟 20 分钟。褪黑激素节律时间的变化以标准时间报告，作者暗示数据与中午同步，“我们知道人类进入太阳时间。” 在这里，我们展示了他们的大量数据最简洁地解释为本地时钟时间和相关光照的夹带，而不是由黎明或中午索引的“太阳时间”。