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Science 325 (5942): 825-826

Copyright © 2009 by the American Association for the Advancement of Science


How Much Sleep Do We Need?

Hyun Hor1, and Mehdi Tafti1,2

Sufficient sleep is necessary for optimal daytime performance and well-being, yet there is a large difference in how much sleep people need, ranging from less than 6 to more than 9 hours. People at all points along this range exhibit no noticeable differences in health and waking performance. Those of us who envy short sleepers would like to reduce sleep duration to the minimum necessary for normal functioning, but do we know what this minimum is? Short sleepers are found in families, as are long sleepers, which suggests a genetic basis for sleep duration. On page 866 of this issue, He et al. (1) add new evidence by showing that a mutation in a transcriptional factor, DEC2, is associated with short sleep in humans and mice.

1 Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
2 Center for Investigation and Research in Sleep, Vaud University Hospital Center, 1011 Lausanne, Switzerland.

E-mail: mehdi.tafti{at}

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