The daily rhythms of peoples genes are disrupted when sleep times shift, according to a small study.
This research may help us to understand the negative health outcomes associated with shift work, jet lag and other conditions in which the rhythms of our genes are disrupted, Derk-Jan Dijk, PhD, FSB, the studys senior author and a professor with the Sleep Research Centre at the University of Surrey in the United Kingdom, said in a news release. A 2012 study in the British Medical Journal linked shift work to a higher risk of myocardial infarction and stroke (www.bmj.com/content/345/bmj.e4800).
Dijk and colleagues placed 22 participants on a 28-hour day in a controlled environment without a natural light-dark cycle. As a result, their sleep-wake cycle was delayed by four hours each day, until sleep occurred 12 hours out of sync with their brain clock and in the middle of what would have been their normal daytime. The team then collected blood samples to measure the participants rhythms of gene expression.
During this disruption of sleep timing, as reported Jan. 21 on the website of the Proceedings of the National Academy of Sciences, there was a six-fold reduction in the number of genes that displayed a circadian rhythm (a rhythm with an approximately 24-hour period). This reduction included many regulators associated with gene transcription and translation, indicating widespread disruption to many biological processes, the researchers said.
The study also revealed which genes may be regulated by sleep-wake cycles and which are regulated by central body clocks. This finding provides new clues about sleeps function as separate from the circadian clock.
The results also imply that sleep-wake schedules can be used to influence rhythmicity in many biological processes, which may be very relevant for conditions in which our body clocks are altered, such as in aging, Dijk said.
Study abstract: www.pnas.org/content/early/2014/01/15/1316335111.abstract