Sleep problems aren't the only health concerns associated with working overnight and shift work. Here's how irregular work hours may be impacting your health

By Diane Peters

5 health risks of shift work

Is it — yawn — time to go to work? If you work outside of nine-to-five hours, you’re not alone. About one quarter of Canadians do some kind of shift work, which can include early or late shifts, and overnight work.

You don’t need us to tell you this type of work is hard on the body. But now there’s mounting medical evidence that irregular work hours can impact your health in long-lasting ways. “When we’re at work when we would normally be sleeping, it presents some challenges. You start to come in conflict with your biological 24-hour clock,” says Cameron Mustard, a health researcher and president of the Institute for Work and Health in Toronto. Here’s how shift work may be impacting you.

1. Your sleep gets messed up

About 10 percent of people doing shift work develop sleep problems, including insomnia, being excessively sleepy and having trouble staying awake at work. Even more common: just not getting enough shut-eye.

“Shift workers are by definition sleep deprived,” says Dr. Charles Samuels, medical director of the Centre for Sleep and Human Performance in Calgary. It’s harder to sleep during the day as it goes against your body’s natural clock, and it’s often too noisy.

How to cope: “People think they can lead a normal life when they do shift work, but they can’t,” says Dr. Samuels. Priority number one has to be protecting your sleep, even if it means missing family time and social functions, or taking naps at odd times. Create a quiet and dark sleep den, keep track of how much sleep you get each week (need eight a night? that means 56 hours) and avoid exercise, caffeine, alcohol and bright lights before you snooze.

2. You gain weight

“When you work in shifts your appetite for high-calorie foods go up,” says Dr. Samuels. As well, numerous studies have linked sleep deprivation to weight gain. The extra weight from working shifts can account for many health concerns, such as a possible increased risk for heart disease, diabetes and cancer.

How to cope: Bring your own food when you’re working and steer clear of the cafeteria and vending machines. Eat small, high-protein meals, and eat often. Dr. Samuels says combining caffeine with carbs (like a muffin and coffee) is the worst, as these snacks can make your insulin spike and lead to weight gain. Exercise as much as you can, but sleep first and work out after you’ve rested.

3. You can get hurt

According to Mustard, the workplace injury rate for those who work overnight shifts is almost 50 percent higher than for day workers. That’s because you’re more tired when you’re working off hours, but also your workplace probably runs on a smaller staff so there are fewer people to help you with risky tasks. (Plus, if you deal with the public, there’s more alcohol use at night, potentially making night jobs more dangerous.

How to cope: Ask for help when you’re lifting or doing something risky while working at night. Use caffeine early in your shift and try to get the trickiest tasks out of the way while you’re perky and alert. Note when you tend to get tired on your shift and pick those moments to take a break.

4. You may develop pregnancy problems

Messing with your body’s natural circadian rhythms seems to have an impact on your ability to have a healthy baby. One Danish study found those who worked fixed nighttime hours had an 85 percent higher miscarriage risk than day workers. And a 2010 study from Italy linked shift work with risk of early delivery and low birth-weight babies.

How to cope: If you are pregnant, take extra care with your sleep and weight. Consider getting help from a sleep clinic if you’re not getting enough shut-eye. A clinic can offer treatments, including light therapy, as well as sleep tips.

5. You could have a higher cancer risk

According to data collected from US Nurses’ Health Study, in which 240,000 nurses were followed for 30 years, women who work for many years on the night shift have an elevated risk of breast, colon and endometrial cancer. Researchers think it’s related to melatonin levels, since those with high levels of the hormone in the study had the lowest cancer risk.

How to cope: If you're working nights over the course of many years, keep up with your screenings. Talk to a sleep doctor about possibly taking melatonin supplements. They’re available over the counter and are safe, but taking them is complex and you’ll need an expert’s guidance.

Diane Peters wrote and researched this article with the assistance of funding from the Canadian Institutes of Health Research (CIHR).

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Web exclusive, December 2011

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