For years, scientists have been looking at the health of people with irregular work schedules, particularly those who work night shifts. They seek to determine the impact that this organization of working time has on our biological functions. A study, published in the Journal of Proteome Research, offers new insight into this question.
Researchers from Washington State University and the Pacific Northwest National Laboratory have found that staggered schedules profoundly disrupt our bodies. “There are brain processes linked to the internal clock that tell us that day is day and night is night, and others (the opposite). When these internal rhythms are disrupted, our body experiences persistent stress, which we believe will have long-term consequences on our state of health.” said Hans Van Dongen, lead author of the study, in a statement.
Hans Van Dongen and his colleagues had proof of this after asking volunteers to work in rotation for three days, that is to say, to do work shifts during the day or during the night. This experiment was carried out in laboratory conditions, so that the academics could measure the biological rhythms of the participants without external events disturbing them.
Blood samples were taken at regular intervals throughout the experiment and were analyzed to identify proteins present in blood immune cells. These proteins follow biological rhythms, which are often synchronized with the internal clock. This is how they regulate many physiological phenomena.
But the researchers found that protein rhythms were profoundly altered by nighttime work. Thus, the proteins regulating blood sugar saw their rhythm almost completely reversed in volunteers working at night. They also found that the processes involved in insulin production and sensitivity, which normally work in concert to keep glucose levels within an optimal range, were no longer in sync in these participants.
The authors of the study believe that this phenomenon is linked to the fact that insulin production fluctuates depending on meals but also on our biological clock. During the night, the body naturally reduces its sensitivity to insulin, which allows for more stable regulation of blood glucose levels in the absence of food intake. This adaptation prevents an abnormal decrease in blood sugar levels. Working at night disrupts this balance, which can have serious medical consequences. Studies have shown that working odd hours is a likely risk factor for type 2 diabetes, as well as obesity and being overweight.
The results of this study show how working at night poses health risks. However, more research is needed to determine whether night shifts induce long-term protein changes.
