Disrupted sleep patterns—such as occur with jetlag or shift work—have long been associated with a wide range of negative health outcomes, and scientists are beginning to understand why. A new study published in the Proceedings of the National Academy of Science illustrated the huge extent to which regular nighttime sleep impacts our bodies.

Researchers at the University of Surrey conducted a genome-wide analysis of how DNA regulation changes as people lose their normal sleep-wake pattern, or circadian rhythm. Twenty-two volunteers had their sleep schedule delayed by four hours each day until they were out of sync by 12 hours, and the expression of every human gene—that is, how much each gene was used—was measured in blood samples collected throughout the study period.

The effects of a shifted sleep pattern were massive. Genes that are normally regulated cyclically according to the time of day were suppressed six-fold, and important genes that regulate many basic biological functions—including hormone levels, immune function, and cell growth and repair—were disrupted. The authors stress that since the number of shift workers is growing and insufficient sleep is a growing problem worldwide, these findings will have increasingly important implications for health care.

(Source: Proceedings of the National Academy of Sciences, January 21, 2014.)

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