RAPID: Collaborative Research: Evolution and variability of modern human sleep patterns

University Of Washington, Seattle WA

Investigators

Abstract

In this RAPID project, the investigators will measure melatonin levels and timing of sleep in two non-industrialized populations that are similar except for access to electricity, to understand how sleep is affected by artificial light and the interaction of artificial and natural light exposures. Because power lines are quickly being extended in the research area, this experimental design is possible during a limited window of time before electricity reaches all communities. The research will contribute to our understanding of underlying biological mechanisms and variability of human sleep patterns. The project will support student training, international research collaborations, and public and community science outreach activities, and has potential relevance for understanding sleep problems in industrialized settings. The investigators will collect data on melatonin levels and sleep timing for individuals in each of two Toba/Qom communities. Participants will wear activity watches and keep diaries to document sleep patterns and quality. Saliva samples will be assayed to determine each individual's daily melatonin onset. The main predictions are that individuals in the community with artificial light will have a later time of daily melatonin onset, that differences will be greatest during the winter, and that any effect of moonlight would be to decrease sleep quality, more so in the population without artificial light. The project will expand our understanding of the spectrum of sleep patterns and sleep-regulatory pressures that may have played distinct roles in human history and evolution, and the ways in which modern societies have modified human sleep patterns.