Hunting for an excuse to get an early night tonight or have a long, lazy lie-in tomorrow? Well, look no further than a new study published in the journal Anaesthesia – it found that pulling an all-nighter actually damages your DNA, something that can lead to health problems. A team of researchers from Hong Kong studied 49 healthy doctors, 24 of whom had to work overnight on-site shifts, which meant they were required to work from late afternoon until the next morning roughly five to six times a month. The study is "the first to quantify DNA damage directly in young adults who are required to work overnight shifts." Blood was taken from all participants following three days of adequate sleep and following night shifts, aka acute sleep deprivation, in the on-call group. The researchers also assessed health information, sleep diaries, and the work patterns of their volunteers. Overall, the team found that at baseline, ie when they’d had enough sleep, the on-call doctors had lower DNA repair gene expression and more DNA breaks than their day-dwelling counterparts. Basically, their DNA was more damaged. DNA repair gene expression decreased and DNA breaks increased directly after the doctors had worked through the night. Therefore, the findings suggest that sleep deprivation and frequent sleep cycle disruption can lead to DNA damage. DNA damage, in turn, has been linked to a whole host of health issues, from heart attacks and diabetes to certain types of cancer. The researchers note in their paper that a meta-analysis of 2 million participants found a link between working night shifts and incidence of breast tumors, although studies on other kinds of cancers have given mixed results. "Although this work is very preliminary, it is clear from the results that even a single night of sleep deprivation can trigger events that may contribute to the development of chronic disease," senior author Dr Siu-Wai Choi of Hong Kong University said in a statement. However, the team note that many other factors could explain why shift workers seem to have a greater predisposition to suffering from chronic illnesses. These range from changes to activity and eating patterns to disruption to the body’s circadian rhythms and sex hormone balances. More research is needed to determine the significance of DNA damage in the relationship between sleep deprivation and disease, as the study’s sample size was pretty small. What’s more, the researchers themselves point out that their night shift participants were younger than their control group as junior doctors are more likely to work nights, a discrepancy that may have affected the results. In addition, all of the participants were Chinese, so the findings can’t be applied to the wider population. "Anaesthetists (and other health professionals) frequently work night shifts and on-call duties, and their work patterns change frequently between night and day work,” said Dr Andrew Klein, a cardiothoracic anaesthetist and Editor-in-Chief of Anaesthesia. “This study is important in that it will allow future researchers to study the impact of changing the way we work and other interventions by evaluating DNA breaks in the same way as the authors of this groundbreaking study have done." Source
