Working against the clock

How can employees and workers reduce the safety risks of shift work?

By Ashley Johnson, associate editor

  • Studies link shift work to sleep disorders, gastrointestinal problems and cancer.
  • Police officers often work overtime and nights. The resulting fatigue can affect their decision-making, potentially threatening their own safety and the safety of the people they serve.
  • Strategies to help workers include training, ingesting caffeine and taking short naps.

Industries such as emergency services, health care, hospitality, manufacturing, telecommunications and transportation rely on 24/7 coverage to boost production and better serve communities and customers. But nontraditional work hours can be hard on employees who face the challenge of trying to remain awake when their bodies would rather be asleep.

“The fundamental flaw is that biologically we are hard-wired to be day creatures, not to be operating around the clock on long, irregular work hours with lots of overtime, with rotating shift patterns, with even what we call steady or fixed [night] shifts,” said Bill Sirios, chief operating officer and senior vice president of Circadian Technologies Inc., a Stoneham, MA-based shift work research and consulting firm.

Sirios, a former shift worker, compared the feeling of shift work to jet lag. Both disrupt the body’s circadian rhythms (internal body clocks), which regulate sleep and activity. Continually disrupting those clocks can have severe consequences, he said. Shift work has been linked to a variety of health problems, and fatigue puts workers at risk for accidents on the job and on the road.

Employers also may pay a price for shift work. Sirios cited Circadian Technologies research that shows shift workers cost an organization $10,000 more each year (adjusted for inflation) than day workers in terms of employee turnover, productivity loss due to human error, absenteeism, health care and workers’ compensation.

Researchers have yet to find a clear-cut answer to the potential negative effects of shift work, but strategies exist to help the country’s estimated 15 million shift workers receive adequate rest and remain alert at work.

Fatigue sets in

Experts often say adults need seven to eight hours of sleep each night. Night workers, who have to catch that rest during the day, typically get less. A poll conducted in 2007 by the Washington-based National Sleep Foundation found about one-third of workers who begin their job after 6 p.m. but before 6 a.m. sleep less than six hours on workdays. Many of these workers have trouble sleeping in the daytime because their circadian rhythms prompt them to be awake. Day sleep also tends to be lighter than night sleep.

When people miss out on sleep, they rack up a sleep debt. “It’s not only about the sleep you got last night, but it’s about the sleep that you received over the past week or even over the past month,” said Christopher Drake, secretary of the NSF board of directors and bioscientific staff investigator at the Henry Ford Hospital Sleep Disorders Clinic and Research Center in Detroit.

“The important idea here is that sleep debt accumulates across nights,” he continued. “And can you pay it back? To some extent.” However, experts are not certain if a person can fully eliminate all of the physiological consequences of years of sleep debt.

Lack of sleep can hinder a person’s ability to make decisions and complete tasks. Research demonstrates going 17 to 19 hours without sleep impairs function as much as or worse than having a blood-alcohol content of 0.05 percent. In the NSF survey, 21 percent of responding shift workers said daytime sleepiness interfered with their daily activities, and 19 percent reported injuring themselves or having an accident on the job in the past year. Almost half indicated they drove drowsy at least once a month.

“The fatigue that occurs during the night shift is not only occurring because these individuals are sleep deprived, but it also occurs because there is a lack of a circadian signal for wakefulness in the middle of the night,” Drake said.

He noted most night workers revert to being day people on their days off, which counteracts their body’s ability to adapt to the work schedule.

Health consequences

Shift work has been associated with adverse health effects ranging from sleep and gastrointestinal disorders to cancer. People who frequently rotate shifts or work nights are at risk for shift work sleep disorder, a condition characterized by insomnia or excessive sleepiness.

With limited food options available in the middle of the night, shift workers may develop unhealthy eating habits. They also may eat at a time when their body is not prepared to properly digest and metabolize food, which can lead to ulcers, Drake said. A study of nurses conducted by researchers at the University of Michigan in Ann Arbor concluded shift work can disrupt the colon’s biological clock, leading to diarrhea, bloating, constipation and abdominal pain.

Extra weight gain, along with high blood pressure and insulin resistance, is part of a cluster of conditions called metabolic syndrome that increase the risk for developing cardiovascular disease. A University at Buffalo study published last year found 30 percent of police officers on the night shift had metabolic syndrome, compared with 21 percent of the general population.

Cancer is another concern. In 2007, a workgroup of the France-based International Agency for Research on Cancer concluded, “Shift work that involves circadian disruption is probably carcinogenic to humans.” That theory is supported by studies documenting a higher risk for cancer among U.S. nurses who worked rotating shifts for several years.

In addition to physical problems, shift workers may suffer emotionally. Their schedule may cause them to miss social events, and they may lack the time or energy to engage with family members after work.

In the line of duty

Research on police officers underscores the larger implications of shift work. It is not uncommon for officers to work more than 18 hours in a row, and approximately 40 percent of them suffer from sleep disorders, said Bryan Vila, director of the Simulated Hazardous Operational Tasks Lab at the Sleep and Performance Research Center at Washington State University Spokane.

Vila spent 17 years in law enforcement and now is a professor of criminal justice. In his opinion, sleep deprivation among officers is important not only from a health standpoint but also in terms of public safety. Although measures exist to deter officers from abusing their discretionary powers, fatigue can compromise their abilities to weigh the consequences of their actions and manage the emotions that come with human confrontation, according to Vila’s research.

Departments must balance providing enough community support with the best schedules to protect officers. “You have to give people enough time so that they can have a good chance of getting home, getting to bed and getting enough sleep to restore themselves before they get back on the job,” Vila said.

A larger cultural shift also might be in order. Sirios described one problem across industries: society rewards overworking. “When that shift worker pulls a double or an extra shift or comes in on his day off or goes that extra yard, we applaud that,” Sirios said. “The reality is, we’re setting people up to fail by condoning that practice.”

He stressed the importance of training for workers and their families on topics such as biology, nutrition, stress management, and balancing work and family life.

Measuring and managing fatigue

Optimizing shift scheduling is one way employers can reduce risks to their workers. The Department of Transportation already limits when and how long commercial motor vehicle drivers may drive, and the Washington-based American Petroleum Institute and the American National Standards Institute have developed guidelines to prevent fatigue among petrochemical workers.

Research from WSU Spokane indicates regulations limiting the number of hours worked also should address shift start times. The study, presented in June at the 24th annual meeting of the Westchester, IL-based Associated Professional Sleep Societies LLC, found shifts beginning between 8 p.m. and midnight yielded poorer performance and less-than-adequate sleep among workers. But predicted fatigue was lower for shifts starting after midnight than shifts starting just before midnight, which researchers said suggests night shifts that begin after midnight might allow workers to sleep more than those that start between 8 p.m. and midnight.

Some researchers advocate a so-called “slow rotation,” in which a person stays on the same shift for two weeks or more instead of weekly rotations, such as one week of days and one week of nights, according to Claire Caruso, research health scientist at NIOSH. She said a backward schedule of going from the evening shift to the day shift is harder on a worker because there is less time between shifts and it requires an earlier awake time, which conflicts with circadian rhythms.

At work, a 30-minute nap can improve alertness. Caruso recommended employers use this strategy: Set aside a quiet room and ensure adequate staffing coverage and supervisor support. Rest and lunch breaks are especially important for workers on 12-hour shifts, she added.

Drinking coffee may be an effective way to stay awake on the job. Researchers in London recently concluded that caffeine reduces mistakes among shift workers, although Drake cautioned that regular coffee drinkers can develop a tolerance to caffeine. Instead of drinking a large cup of coffee before work, he recommends small doses every few hours during a shift.

Drake believes employers have a responsibility to identify employees who are excessively sleepy. “There needs to be more open-mindedness on the part of employers to intervene and to go the extra mile, to do more than just recognition but also to bring in experts to help truly address these problems in a systematic way through diagnosis and treatment,” he said.

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