Night work 'throws body into chaos'

Doing the night shift throws the body "into chaos" and could cause long-term damage, warn researchers.

Shift work has been linked to higher rates of type 2 diabetes, heart attacks and cancer.

Now scientists at the Sleep Research Centre in Surrey have uncovered the disruption shift work causes at the deepest molecular level.

Experts said the scale, speed and severity of damage caused by being awake at night was a surprise.


The human body has its own natural rhythm or body clock tuned to sleep at night and be active during the day.

It has profound effects on the body, altering everything from hormones and body temperature to athletic ability, mood and brain function.

The study, published in Proceedings of the National Academy of Sciences, followed 22 people as their body was shifted from a normal pattern to that of a night-shift worker.

Blood tests showed that normally 6% of genes - the instructions contained in DNA - were precisely timed to be more or less active at specific times of the day.

Once the volunteers were working through the night, that genetic fine-tuning was lost.

"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," said Dr Simon Archer, one of the researchers at the University of Surrey.

Fellow researcher Prof Derk-Jan Dijk said every tissue in the body had its own daily rhythm, but with shifts that was lost with the heart running to a different time to the kidneys running to a different time to the brain.

- BBC.co.uk