Work random hours? Inconsistent shifts can be harmful to your health, study warns

WATERLOO, Canada — The typical 9-5 workday can be a drag for many of us, but a new study may make many appreciate their traditional working hours. Researchers from Waterloo University say inconsistent shift work is linked to a number of adverse health outcomes and can even increase susceptibility to various infections. Interestingly, male and female workers often experience different complications.

Much of these problems are linked to the human body’s natural circadian rhythm, or internal clock. Constantly working, sleeping, and eating at different times of the day take its toll eventually.

To study all of this, the team at Waterloo designed mathematical model capable of examining how circadian rhythm fluctuations may or may not influence the immune system.

“Because our immune system is affected by the circadian clock, our ability to mount an immune response changes during the day,” says Anita Layton, professor of Applied Mathematics, Computer Science, Pharmacy and Biology at Waterloo, in a release. “How likely are you to fight off an infection that occurs in the morning than midday? The answer depends on whether you are a man or a woman, and whether you are among quarter of the modern-day labour force that has an irregular work schedule.”

Next, another set of mathematical models were put together. This time, one set was constructed for men, and another for women. These models were created via a number of complex considerations including core clock genes and their related proteins, as well as the regulatory mechanism of pro- and anti-inflammatory mediators. By adjusting the “clock” on these models, researchers were able to simulate how various circadian changes may influence health outcomes.

The ensuing results indicate individual immune responses depend on the time of infection. According to the research, just before bed is the worse time to be infected. Just around bedtime is when our bodies are least prepared to create the pro- and anti-inflammatory mediators that are integral to fighting off pathogens. Beyond that, gender also appears to impact infection severity.

“Shift work likely affects men and women differently,” concludes Stéphanie Abo, a PhD candidate in Waterloo’s Department of Applied Mathematics. “Compared to females, the immune system in males is more prone to over-activation, which can increase their chances of sepsis following an ill-timed infection.”

The study is published in PLOS Computational Biology.