Night shifts and jet lag disrupt genetic rhythm

Date: Jan-21-2014A new study from the UK finds that when we shift our sleep time, it disrupts the

daily rhythms of our genes. Researchers from the University of Surrey report their findings in a study to be published

in the Proceedings of the National Academy of Sciences.

The study also shows that some genes follow sleep-wake cycles, and some are regulated by

central body clocks.

Senior author Derk-Jan Dijk, professor of Sleep and Physiology and director of Surrey's

Sleep Research Centre, says:

"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."

"The results also imply that sleep-wake schedules can be used to influence rhythmicity in

many biological processes," he adds, "which may be very relevant for conditions in which our body clocks

are altered, such as in ageing."

Night shift working linked to range of health problems

Working a night shift is classed

as a "probable human carcinogen" because of evidence linking it to a range of health

problems and diseases.

In July 2013, the BMJ published evidence from Canada that showed long-term night shift working is linked to

raised risk of breast cancer in women.

Other studies have also suggested shift workers carry a higher

diabetes risk, and they also have a   higher risk for heart attacks and strokes.

For this new study, the team invited 22 participants to spend time in a controlled

environment without a natural light-dark cycle.

They put the participants on a 28-hour day pattern, which progressively delayed their

sleep-wake cycle by 4 hours per natural day until their sleep was 12 hours of of sync with

their brain clock and occurred in the middle of what would otherwise have been their normal

daytime.

From blood samples collected from the participants the researchers were able to analyze what

was happening to the rhythms of gene expression under this shifted sleep-wake pattern.

Six-fold reduction in rhythmic gene expression

They found a six-fold reduction in the number of genes that displayed a circadian rhythm (a

pattern that follows an approximately 24-hour cycle).

These included many regulator genes involved with transcription and translation - which

would indicate widespread disruption to many biological processes.

Genes involved with transcription and regulation - the transcriptome - interpret the DNA

code for making proteins and controlling cell behavior.

Thus the results of the study suggest that disruption of our sleep-wake cycle interferes

profoundly with the rhythm of genes that switch other genes on and off and fine-tune the biological processes in our bodies.

Co-author Dr. Simon Archer, a reader in Chronobiology at Surrey, says:

"Over 97% of rhythmic genes become out of sync with mistimed sleep and this really explains

why we feel so bad during jet lag, or if we have to work irregular shifts."

A grant from the UK's Biotechnology and Biological Sciences Research Council (BBSRC) helped

finance the study.

Written by Catharine Paddock PhD




View all articles written by Catharine, or follow Catharine on:




Copyright: Medical News Today

Not to be reproduced without the permission of Medical News Today.

Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.