Those who work the night shift are already well aware of how much the schedule can throw off your day-to-day life. But they may not realize that it's harmful to their health. A new study found that found that those who work rotating shifts and inconsistent hours have a shorter life span than their 9-5 peers.

In the U.S., roughly 6.8 million Americans perform shift work, whether it's the night shift or a rotating work schedule. They include police officers, firefighters, waitresses, doctors, truck drivers, air traffic controllers, and millions of other workers. More often than not, workers adhere to these schedules because their employment depends on it, putting in their time until they can get a better shift or a more consistent schedule. But most shift workers have no idea how damaging this type of schedule can be to their overall health.

Research on work habits and health have consistently shown that shift work — the night shift in particular — results in a 40 percent higher risk of cardiovascular disease and a greater risk for diabetes, obesity, depression and on-the-job injuries. The health risks are so concrete that the World Health Organization has listed shift work as a likely carcinogen.

Now, a new study published in the American Journal of Preventive Medicine has found that shift work may shorten your life span. The research, which was compiled from the medical records of 75,000 American nurses over a 22-year period, showed that rotating shifts were linked to an increased rate of mortality for the study's participants.

Over a five-year period, nurses who worked shift work were 11 percent more likely to die over the course of the study than the participants who worked more consistent schedules. Shift work also caused a 19 percent increase in cardiovascular disease and a 25 percent increased risk of dying from lung cancer.

Researchers have not yet pinpointed the cause for the health risks of shift work, but they speculate that the fragmented sleep caused by intermittent schedules can wreak havoc on overall health, weakening the immune system and leaving workers more susceptible to illness.

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