Could Shift Work Hurt Your Health?

If you work nights or your job requires you to rotate shifts, you may be at a heightened risk for developing type 2 diabetes. In fact, the odds of developing the chronic illness are 9% higher for shift workers than for those who didn't work shifts. The research, published in Occupational and Environmental Medicine, was a compilation of data from a dozen earlier studies focusing on more than 225,000 individuals, including nearly 15,000 with diabetes.

It's long been known that individuals who work shifts are at risk for weight gain, along with increased body fat. Since obesity and a higher level of body fat are both risk factors for type 2 diabetes, this means shift workers are more likely to develop the disease.

Why are people who work shifts at risk for weight gain and greater body fat? "Shift work may interfere with the normal routine of the light-dark cycle, and with sleeping and eating patterns," emailed senior study author Zuxun Lu, PhD, of the School of Public Health at Tongji Medical College, Huazhong University of Science and Technology in Wuhan, China. Disrupted sleeping and eating patterns, which can lead to poor sleep quality and poor eating habits, can accelerate the onset of type 2 diabetes in some people, he adds.

A disruption in hormone functioning could also place shift workers at risk for type 2 diabetes, says New York City-based Karin Hehenberger, MD, PhD, the founder of Lyfebulb, an educational and social platform that helps individuals with chronic illnesses. "When you don't sleep at night, not only is your circadian [relating to the 24-hour cycle] rhythm disturbed, but a number of hormones are disturbed as well," she explains. "Both cortisone and adrenaline [hormones released by the body] can contribute to insulin resistance, and it's likely that a shift worker can have abnormally high levels of these." Insulin is a hormone that helps the body absorb blood sugar and use it for energy; insulin resistance, the inability of the body to use insulin effectively, can lead to type 2 diabetes.

Shift workers who work nights often snack more than other workers in order to stay awake. "And they tend to snack on the wrong foods, such as foods that are high in carbohydrates and sugar, to give them energy," Hehenberger adds.

Stress may also play a role, says Spyros Mezitis, MD, MPH, an endocrinologist at Lenox Hill Hospital in New York City. "There is a level of stress in shift work," he says. "It's harder to work at night, and to try to control your weight."

More research is needed in this area, he feels. "This was an observational study but we need a double-blind, placebo-controlled study to verify the results," Mezitis says. (Observational studies observe and record data on patients over time, while in controlled studies, participants are assigned to one of two groups. Subjects in one group receive treatment while those in the other receive a placebo; data is recorded and analyzed. In double-blind placebo-controlled studies, neither the participants nor the investigators know who is receiving the treatment and who is receiving the placebo.)

Zuxun Lu agrees: “More prospective studies with a long follow-up period are warranted to replicate our findings and reveal the underlying biological mechanism," he says.

Meanwhile, if you work shifts, you may be able to lower your diabetes risk by:

  • Snacking on the right foods. Instead of chips and cookies, try a small handful of nuts, or an apple spread with almond butter or peanut butter. Avoid sugary juices and carbonated soft drinks unless they are sugar-free.
  • Making time for regular physical activity. "If you don't set aside time for it, it is easy to get caught up and not do exercise," says Supneet Saluja, MD, of the Center for Endocrinology at Mercy Medical Center in Baltimore. "Multiple short spurts of exercise of 10 to 15 minutes in duration are as effective as one long session. And this is easier to manage as a shift worker."
  • Educating yourself about the symptoms of type 2 diabetes and watching closely to see if you are developing any of these symptoms. "If you have early symptoms of diabetes, it would be helpful to limit your exposure to shift work," Zuxun Lu advises. Symptoms of diabetes can include increased thirst, frequent trips to the bathroom, blurry vision, and muscle cramps.
  • If you already have diabetes and are on insulin, consider getting a pump. "If you are an insulin-treated diabetic, shift work may make it challenging to maintain good glycemic control," Saluja says. "An insulin pump may be a good option in this situation as it allows more flexibility."

Supneet Saluja, MD, reviewed this article.


Spyros Mezitis. Phone interview, September 12, 2014.

Karin Hennenberger. Phone interview, September 17, 2014.

Supneet Saluja, Phone interview, September 17, 2014.

Zuxun Lu. Email interview September 19, 2014.

Lehman, Shereen. "Shift Work Linked to Greater Diabetes Risk." Reuters Health. 29 August 2014. 

Yong Gan et al. "Shift Work and Diabetes Mellitus: A Meta-Analysis of Observational Studies." Occupational and Environmental Medicine. Published online 16 July 2014. doi:10.1136/oemed-2014-102150 

"Insulin Resistance and Prediabetes." National Diabetes Information Clearinghouse. Page last updated September 10, 2014.