lack of sleep permanently damage DNA and raises risk of cancer, study shows.
The study at The University of Hong Kong looked at 49 working doctors from two local hospitals, 24 of whom had to work overnight on-site calls.
When a doctor receives such a call – on average they get five to six per month – they must work from late afternoon to early morning the next day.
In the study the participants got between two and four hours of sleep during calls, with three getting as little as a single hour’s shut-eye.
The remaining 25 doctors were not expected to work these hours.
Researchers took blood samples from all doctors after they had had three nights of healthy sleep.
Then blood samples were taken the morning after a night shift when doctors were sleep deprived.
The findings, published in the journal Anaesthesia, showed doctors who worked night shifts had 30 per cent more breaks in their DNA compared to those who did not.
What’s more, the DNA damage increased a further 25 per cent after a night of sleep deprivation.
DNA repair was also lower in the doctors who didn’t get adequate sleep, which can cause cell death.
The study authors wrote: ‘DNA damage is a change in the basic structure of DNA that is not repaired when the DNA is replicated.
‘Double‐strand breaks are particularly hazardous, as repair failure causes genomic instability and cell death, whereas disrepair can lead to inappropriate end‐joining events that commonly underlie oncogenic transformation [cancer formation].
‘Sleep deprivation in shift workers is associated with adverse health consequences.
‘Increased DNA damage has been linked to the development of chronic disease.
‘This study demonstrates that disrupted sleep is associated with DNA damage.’
Although the findings are preliminary, Dr Gordon Wong Tin-chun, co-author of the study and an associate professor at HKU’s department of anaesthesiology, said there is an indication the sleep disruption is ‘not good’ for your genes.
He said: ‘[Such conditions] may increase chances of developing diseases from genetic mutations such as cancers’.
It is not clear, according to the researchers, why DNA damage occurs due to a lack of sleep.
Dr Wong Tin-chun said the findings of the study might be applicable to people who had shift patterns similar to doctors.
They hope the study will raise awareness on the importance of getting enough sleep.
The study also highlighted the doctors it focused on were ‘young and healthy’, and therefore more tolerant of a lack of sleep.
‘Maybe you should consider looking into your [sleep habits] and treating sleep with a bit more respect,’ Dr Wong Tin-chun said.
The recommended hours of sleep for people vary across age groups.
An adult aged between 18 and 60 should get at least seven hours of sleep per night, according to the website of the US Centers for Disease Control and Prevention.
Figures from the Royal Society for Public Health estimate the average person sleeps for 6.8 hours a night, but the the NHS recommends people get eight hours.
Regular poor sleep puts you at risk of serious medical conditions, including obesity, heart disease and diabetes.
It shortens your life expectancy, according to the NHS, and has previously been linked to a greater risk of cancer.