Sleep adaptations to seasonal changes in light and temperature

该奖项是NSF的社会，行为和经济科学（SBE）博士后研究奖学金（SPRF）计划和SBE的生物人类学计划的一部分。SPRF计划的目标是为学术界，工业或私营部门和政府的科学事业准备有前途的早期职业博士级科学家。SPRF的奖励包括在知名科学家的赞助下进行两年的培训，并鼓励博士后研究员进行独立研究。NSF致力于促进来自科学界各部门的科学家，包括来自代表性不足的群体的科学家参与其研究计划和活动;博士后期间被认为是实现这一目标的专业发展的重要水平。每个博士后研究员必须解决推进各自学科领域的重要科学问题。在洛杉矶的加州大学的杰罗姆西格尔博士的赞助下，这个博士后奖学金支持一位早期职业科学家研究现代狩猎采集人群的睡眠模式。大多数人发现没有闹钟和一杯咖啡就无法开始新的一天，但San狩猎采集者没有这些设施。在人类进化过程中，早期人类需要弄清楚他们每天需要什么时间醒来，每天晚上睡觉，以便在传统狩猎采集生活方式的背景下最大限度地提高他们的生殖成功率。桑人今天过着类似的生活方式，大多数植物性食物都是从野生资源中收集的，所有的肉都来自用弓箭狩猎野生动物。他们住在一个偏远的村庄，那里没有电，也没有自来水。人们几乎把所有的时间都花在户外，包括睡在户外，除了预期下雨的时候。对这一人群和其他两个类似人群的早期研究发现，每晚睡眠时间为5.7-7.1小时，与美国观察到的典型睡眠时间相似。睡眠通常在日落后几个小时开始，并在24小时内最冷的时候结束。人们在冬天的几个月里每晚比夏天多睡一个小时。三个独立人群睡眠模式的相似性可能是由对自然环境的生物适应所驱动的。这项研究的后续研究调查了环境条件如何影响桑人的睡眠。一年中睡眠时间和持续时间的变化，用腕戴式加速度计测量，可以与天气数据一起分析，以评估光线和温度对睡眠的相对影响。此外，使用便携式EEG监测器，可以评估和比较夏季和冬季之间夜间REM和非REM的分布，此时睡眠持续时间每晚相差约一小时。这项研究将确定温度作为人类睡眠状况预测因子的重要性，并开始解释为什么狩猎采集人群的睡眠在一年中会有所不同。这些见解对于更好地确定我们进化的睡眠生物学如何与现代西方条件发生冲突，以及这种冲突如何增加各种睡眠疾病的风险非常重要。它们也是更好地理解早期人类祖先从热带气候的树上睡觉（如黑猩猩）过渡到今天的睡眠模式时所面临的一些适应性挑战的重要第一步。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

This award was provided as part of NSF's Social, Behavioral and Economic Sciences (SBE) Postdoctoral Research Fellowships (SPRF) program and SBE's Biological Anthropology program. The goal of the SPRF program is to prepare promising, early career doctoral-level scientists for scientific careers in academia, industry or private sector, and government. SPRF awards involve two years of training under the sponsorship of established scientists and encourage Postdoctoral Fellows to perform independent research. NSF seeks to promote the participation of scientists from all segments of the scientific community, including those from underrepresented groups, in its research programs and activities; the postdoctoral period is considered to be an important level of professional development in attaining this goal. Each Postdoctoral Fellow must address important scientific questions that advance their respective disciplinary fields. Under the sponsorship of Dr. Jerome Siegel at the University of California, Los Angeles, this postdoctoral fellowship award supports an early career scientist investigating sleep patterns in a modern hunter-gatherer population. Most people find it impossible to start their day without an alarm clock and a cup of coffee, but San hunter-gatherers do not have such amenities. During human evolution, early humans needed to figure out what time they needed to wake up each day and go to sleep each night in order to maximize their reproductive success in the context of a traditional hunter-gatherer lifestyle. The San population lives a similar lifestyle today, with most plant food being collected from wild sources, and all meat coming from hunting wild animals with bow-and-arrow. They live in a remote village where they do not have access to electricity or running water. People spend almost all of their time outside, including sleeping outside, except for when rain is expected.Earlier work in this and two other similar populations found that sleep duration is 5.7-7.1 hours per night, similar to the typical sleep duration observed in the United States. Sleep is normally initiated several hours after sunset and terminated at the coldest time of the 24-hour day. People sleep one hour longer per night in the winter months than they do in the summer months. These similarities in sleep patterns across three independent populations may be driven by biological adaptations to the natural environment. The follow-up research in this fellowship investigates how ambient conditions affect sleep within the San population. Changes in sleep timing and duration across the year, measured with wrist-worn accelerometers, can be analyzed in tandem with weather data to assess the relative influence of light and temperature on sleep. In addition, using portable EEG monitors, the distribution of REM and non-REM across the night can be assessed and compared between the summer and winter months, when sleep duration differs by about one hour per night. This research will identify the importance of temperature as a predictor of human sleep conditions, and begin to explain why sleep varies across the year in hunter-gatherer populations. These insights are important to better identify how our evolved sleep biology clashes with modern Western conditions, and how that clash may increase the risk of various sleep pathologies. They are also important first steps towards better understanding some of the adaptive challenges that faced early human ancestors as they transitioned from sleeping in trees in tropical climates, like chimpanzees, to the patterns of sleep conditions seen today.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.