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How Work Schedules Effect Sleep
Studies show that 85 percent of police officers, 80 percent of regional pilots, and 48 percent of air-traffic controllers nod off on the job. And a frightening 41 percent of medical workers admit they’ve made fatigue-related errors. In one survey alone, 19 percent report “worsening” a patient’s condition. What’s more, the Exxon Valdez grounding, the space shuttle Challenger accident, and the Three Mile Island nuclear accident have all been blamed, at least in part, on fatigue related to sleep loss.
Besides the negative consequences resulting on the job, shift workers are feeling the effects of their schedules. A study of 437 day workers and 246 rotating shift workers at the Universidad de Buenos Aires in Argentina found that shift workers have seriously lower levels of serotonin, a hormone that plays a role in regulating sleep and mood, than their day-working counterparts. Unfortunately, lower levels of serotonin are associated with anger, depression, and anxiety, as well as poor sleep. Another study, conducted by Harvard Medical School—this one of more than 78,000 women who worked rotating night shifts over a 10-year period—found that shift work significantly increased a woman’s risk of breast cancer.
A second team of Harvard researchers studied the same group, and they found that women who worked a rotating night shift at least three nights per month for 15 or more years had an increased risk of colorectal cancer.
And a third team of Harvard researchers studied more than 53,000 women who worked rotating shifts and found that night work increased the women’s risk of endometrial cancer by 47 percent—and actually doubled the risk of endometrial cancer in obese shift workers.
It’s this type of research that led the World Health Organization late in 2007 to classify shift work as a “probable” cause of cancer—a position that the American Cancer Society indicates it is likely to follow.
Most of the 25 million hardworking American women who work rotating night shifts get between five to seven hours less sleep each week than their non-shift friends and neighbors, says sleep researcher Kar-Ming Lo, M.D., FCCP, a critical-care specialist in the Akron, Ohio, Summa Health System.
It’s a seemingly insignificant deficit, but two hours of sleep loss, studies report, have the same effect on your brain as knocking back two or three 12-ounce beers. It’s also an amount that week after week, year after year, may build up to a huge effect.
Most workers try to catch up on weekends, but how much that helps is a matter of intense debate and millions of research dollars. Given the complexity of individual biology and the variables of each individual work situation, soon-to-be-released studies from the University of Pennsylvania suggest that recovery from sleep deprivation may not be as simple as sleeping an extra four hours on Saturday and Sunday to make up for the four you lost during the week.
So why aren’t our shift workers getting the sleep they need?
“There are three main reasons,” says Dr. Lo.For one thing, our bodies are hardwired to be alert and active during the day and sleepy at night. But when you sleep during the day, many of the brain chemicals that keep the brain asleep in response to darkness are simply not released—or not released in the amounts you need for good sleep and optimal health.
As a result, says Dr. Lo, shift workers miss out on a portion of the restorative sleep you need to build and repair the body. Shift workers also get less of the other types of sleep, which affect mood, memory, and the ability to make quick decisions.
A second reason shift workers aren’t getting proper sleep is that sleeping during the day runs against the grain of society. You can come home and lie down to sleep at 9 or 10 o’clock every morning, but the rest of the world goes on. Dogs bark, trash haulers pick up the recycling, hedge trimmers keep the world neat.
What’s more, since most people don’t understand the biological importance of sleep, your need to sleep may not be respected—even within your own family. Your children may wake you and demand attention as they run in the door after school at 3 o’clock, or your husband may try to initiate sex on the one day all week you have to sleep in. Studies reveal that shift work actually increases the risk of divorce by 57 percent.
It’s a tough way to make a living.
What’s really diabolical, however, is the fact that over the course of a week, the shift workers’ biological clocks will begin to adjust. That sounds like a good thing, but come the weekend, many shift workers try to be more a part of the family and live life on the family’s schedule. One mother may get only a few hours of sleep, then get up and go to her daughter’s T-ball game. She’ll come home and nap, get up again, make dinner, and eat with her family. Another mom may cut short her sleep to take a child to the doctor’s, then spend a little time shopping at the mall. She’ll nap during the afternoon, then make dinner and eat with the family.
Unfortunately, says Dr. Lo, those innocent attempts to participate in family life on the family’s schedule is enough to throw all the adjustments her biological clock made the week before into disarray. The result is that she’ll feel cranky, exhausted, and sleep deprived for the first two days of the next week—the time it will take her body to readjust.
You think jet lag is bad?
“The lag from shift work is worse,” says Dr. Lo.
Soon-to-be-released studies from the University of Pennsylvania suggest that recovery from sleep deprivation may not be as simple as sleeping an extra four hours on Saturday and Sunday to make up for the four you lost during the week.
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