Night work is already linked to higher diabetes and cancer rates.
Night work is already linked to higher diabetes and cancer rates.

Working a few night shifts is enough to change gene expression and dampen the body’s ability to fight off attacks, a new Canadian study reveals.

Researchers at McGill University simulated a night shift in which eight healthy people faced a 10-hour delay of their typical sleep time over four days. RNA extracted from blood samples taken before and after the sleep change showed a “marked reduction” in sleep/wake rhythms, proof that key biological processes were affected.

The team analyzed sleep-habit influence on 20,000 genes and found 25% of rhythmic genes lost their biological rhythm after the experiment.

Most notable: Staying up at night reduced the natural killer cell-mediated immune response and led to a loss in temporal coordination between the human circadian rhythm and the external environment.

“We uncovered key biological processes and regulatory molecules that are altered during this night shift protocol and that may contribute to the development of health problems on the long term,” wrote lead author Laura Kervezee, postdoctoral fellow at McGill’s Douglas Mental Health University Institute.

Kervezee and her co-authors said understanding the molecular mechanisms that underlie those associations will be instrumental in advancing the diagnosis, prevention and treatment of shift work-related health concerns.