People in some factories and other workplaces have to work in shifts. While for some it is not a big problem at all, other people take a long time to adapt and feel tired most of the time. The usual explanation is different levels of stamina and different daily habits, however, now scientists from Finland discovered genetic reasons of tolerance to shift work.
In short, it is all about melatonin receptors. Shift work causes disruptions in daily work/rest patterns and melatonin is very significant in healthy sleep. In fact, some shift workers suffer from sleep disorders, while day time fatigue is rather common between them. Scientists studied entire genome to find that there is a common variation in the melatonin receptor 1A (MTNR1A) gene, which can be linked to the job-related exhaustion experienced by shift workers. Having in mind modern research methods, methodology of this study was rather simple.
This study involved a number of Finnish shift workers from many different lines of work, from different kinds of jobs. They were asked to report any day time fatigue they were feeling and other work-related issues. Then researchers analysed their genome, trying to find some differences between workers who could tolerate shift work and those who faced continuous problems. And thus scientists concluded that melatonin receptor gene expression determines the level of tolerance to this kind of job.
Scientists also found that some variations in the melatonin receptor gene, called MTNR1A, is also involved in the process. It is involved in the mechanism, stabilizing circadian rhythm according to environmental condition. It explains why light exposure at night disrupts the circadian rhythm of shift workers. All this information that scientists uncovered is very interesting and explains a lot. However, they tend to be humble about their own discoveries. Professor Tiina Paunio, leader of the study, said: “The variant we have now discovered can only explain a small part of the variation between individuals, and it cannot be used as a basis to determine a person’s tolerance to shift work”.
People have to make choices about their life and work. Those, who cannot tolerate shift work, should search for another job – completely disrupted circadian rhythm can cause tremendous consequences on one’s health.