According to a study published in PNAS, the disruption shift work causes to circadian rhythms has quick and profound effects on the body. Scientists followed twenty-two people as they transitioned from the day shift to night shift, taking blood samples before, during, and after the shift change. About 6% of our genes are precisely timed—synced to our circadian rhythms. By delaying sleep, the functions of those genes are disrupted. In fact, blood samples showed that they were disrupted almost immediately.
Need another reason to ditch the night shift? Night shift workers might have an increased risk of heart attack—possibly one consequence of genetic disruption.