Numerous studies have shown that shift work, that is – a night shift, an early morning shift, or a rotating work schedule – can have an adverse effect on health. Now, a study from McGill University’s Douglas Mental Health University Institute in Montreal, Canada, may show why.
The small study, published in the Proceedings of the National Academy of Sciences, simulated the effects of a five-day shift work schedule on the expression of 20,000 genes. Eight healthy volunteers were deprived of light or sound cues to the time of day and did not have access to their phones or laptops. On the first day of the study, the volunteers followed their normal sleep schedule, but on the remaining four days, they remained awake at night and slept during the day. Researchers collected blood samples and measured gene expression at different times within a 24-hour period on the first and last day.
According to the researchers, most genes that regulate important biological processes, including the immune system and metabolism, are unable to adapt to new patterns of sleeping and eating, and remained tuned to their normal daytime biological clock rhythms. The results of this study suggest that health problems associated with shift work, such as an increased risk for diabetes, obesity, and heart disease, may be due to molecular changes in the body.