Although many people still work a traditional 9-to-5 workday, there are millions of Americans that work the evening shift, night shift, rotating shift, or other employer arranged irregular schedules, according to the Bureau of Labor Statistics. Shift work can have an affect on your health and therefore it’s important for shift workers to make sleep a priority.

There are several reasons why night shifts wreak such havoc on sleep, according to Dr. Mark R. Smith, postdoctoral fellow in the Wright Laboratory at the University of Colorado Boulder.

“The human biological clock is hardwired to be awake during they day and sleep at night,” he says. “A large majority of shift workers attempt to work when their bodies are actively promoting sleep. Sleeping during the daytime is a difficult endeavor for most people because the biological clock doesn’t usually adjust to night shifts and promotes wakefulness, not sleep, during daytime hours.”

Depending on their biological clock, some people may be more affected than others. A night owl might cope relatively well with night shift work, while most morning people cope relatively poorly, says Smith. Conversely, a morning person might fare relatively better with a work shift that has an early morning start time, whereas the night owl would suffer with such a work shift.

There are some symptoms that shift workers can look for to determine whether they could have a sleep problem such as shift work disorder.  A primary symptom is sleepiness when attempting to remain awake. Other signs include fatigue and difficulty sleeping, specifically when working night shifts, but not on days off.

A board-certified sleep physician can diagnose and help you manage shift work disorder. Some of the available treatments include bright light therapy, sleep medications and melatonin supplements.

This disorder can be difficult to treat at times because these options don’t always address the actual cause of the “disorder”, which is misalignment between the biological clock and the work shift, adds Smith. “Because the biological clocks of most shift workers don’t change substantially, staying alert during each and every night shift and sleeping during each and every day, goes against the grain of our physiology.”