Genes Out of Sync with Day Time Sleep?

Whether it’s caused by jet lag or sleep-disordered breathing, sleeping during the day is a familiar coping mechanism for many sleep-deprived people. However, a new study suggests that about one third of a person’s genes can be “disrupted” by a mid day snooze.

This type of “shifted sleep” appears to disrupt gene activity even more than not getting enough sleep, according to research published in Proceedings of the National Academy of Sciences. The article “Mistimed sleep disrupts circadian regulation of the human transcriptome” is presented by British researchers who put 22 healthy, young volunteers in a dimly lit sleep lab for three days.

“During the first day, they disrupted the participants’ sleep at regular intervals to reset their body clock to its innate rhythm,” writes HealthDay reporter Brenda Goodman. “On the second and third days, the volunteers ate and slept on a 28-hour schedule, so their longest period of sleep was from noon until about 6:30 p.m.”

Researchers reportedly drew blood samples all three days so they could watch what happened to the timing of gene activity. During the first day, when the body reset its circadian rhythm, nearly 1,400 genes—about 6.4% of all genes that were analyzed—were in sync with that rhythm. On the days of shifted sleep, however, the number of genes tied to the body’s clock dropped dramatically, to 228 genes, or only 1% of genes analyzed.

“Researchers estimated that the sleep disruptions would ultimately impact about a third of a person’s genes,” writes Goodman. “That’s an even greater disruption than scientists saw in a previous study when they tested the effects of sleep deprivation on gene activity. In that study, which had study volunteers sleeping about five and half hours each night, the number of genes that were in sync with the body’s clock dropped from about 9% to 7%.”

“These are quite fundamental processes that are being affected,” said senior study author Derk-Jan Dijk, a professor of sleep and physiology at the University of Surrey, in the United Kingdom. “We think that may be related to the negative health outcomes associated with long-term shift work.

Click here for abstract

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