Hadza sleep biology: Evidence for flexible sleep-wake patterns in hunter-gatherers
Hadza sleep biology: Evidence for flexible sleep-wake patterns in hunter-gatherers
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DOI：
10.1002/ajpa.23160
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发表时间：
2017-03-01
影响因子：
2.8
通讯作者：
Nunn, Charles L.
中科院分区：
文献类型：
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作者：
Samson, David R.;Crittenden, Alyssa N.;Nunn, Charles L.
目标跨文化睡眠研究对于破译现代睡眠表达是否是最近选择压力的产物，或者是与祖先睡眠生态进化不匹配的一个例子至关重要。我们与坦桑尼亚赤道地区的狩猎采集社区哈扎 (Hadza) 合作，以更好地了解祖先的睡眠模式并测试与睡眠分段相关的假设。方法我们使用体动记录仪分析 33 名志愿者总共 393 天的睡眠-觉醒模式。进行线性混合效应模型来评估睡眠持续时间和质量的生态预测因子。此外，还使用函数线性模型（FLM）来表征24小时平均昼夜节律模式。结果与后工业化的西方人群相比，哈扎人的睡眠时间较短（6.25小时）、质量较差（睡眠效率=68.9%），但昼夜节律较强。睡眠持续时间受到活动量增加、年龄、光照（勒克斯）暴露和月相的负面影响，而受到白天长度和夜间平均温度增加的正面影响。平均每日小睡比率（即小睡天数的比例）为 0.54（SE=0.05），平均小睡时间为 47.5 分钟（SE=2.71；n=139）。 讨论这项研究表明，小规模觅食种群的昼夜节律比西方种群更容易受到生态环境的影响。此外，哈扎人的睡眠特点是灵活，清晨睡眠时间一致，但依赖于白天的机会性小睡。我们认为睡眠-觉醒模式的可塑性一直是人类进化中自然选择的目标。
ObjectivesCross-cultural sleep research is critical to deciphering whether modern sleep expression is the product of recent selective pressures, or an example of evolutionary mismatch to ancestral sleep ecology. We worked with the Hadza, an equatorial, hunter-gatherer community in Tanzania, to better understand ancestral sleep patterns and to test hypotheses related to sleep segmentation.MethodsWe used actigraphy to analyze sleep-wake patterns in thirty-three volunteers for a total of 393 days. Linear mixed effects modeling was performed to assess ecological predictors of sleep duration and quality. Additionally, functional linear modeling (FLM) was used to characterize 24-hr time averaged circadian patterns.ResultsCompared with post-industrialized western populations, the Hadza were characterized by shorter (6.25 hr), poorer quality sleep (sleep efficiency=68.9%), yet had stronger circadian rhythms. Sleep duration time was negatively influenced by greater activity, age, light (lux) exposure, and moon phase, and positively influenced by increased day length and mean nighttime temperature. The average daily nap ratio (i.e., the proportion of days where a nap was present) was 0.54 (SE=0.05), with an average nap duration of 47.5 min (SE=2.71; n=139).DiscussionThis study showed that circadian rhythms in small-scale foraging populations are more entrained to their ecological environments than Western populations. Additionally, Hadza sleep is characterized as flexible, with a consistent early morning sleep period yet reliance upon opportunistic daytime napping. We propose that plasticity in sleep-wake patterns has been a target of natural selection in human evolution.