Shift work sleep disorder is a reality of today’s world, but there are treatment options.

By Gary Zammit, PhD

From doctors on call during night and weekend hours, to policemen who routinely patrol our streets, to those in the transportation industry and factory workers whose shift ends at dawn, America could be considered “the country that never sleeps.” Pressure to raise efficiency and productivity coupled with the very nature of our 24/7 lifestyles demand that individuals work shifts outside of the typical “9-to-5” business day. While shift work allows corporate enterprise to operate around the clock, create jobs, and provide cheaper products and services, it often presents serious consequences for its workers. With over 15 million Americans (20% of the workforce)1 engaged in shift work, many individuals fall prey to shift work sleep disorder (SWSD), a circadian rhythm sleep disorder that affects 5% to 10% of shift workers.

SWSD is defined as the complaint of insomnia or excessive sleepiness that is temporally associated with work periods occurring during the habitual sleep phase.2 Such work periods or shift work schedules include night shifts, evening shifts, split shifts, rotating shifts, and extended duty hours. These schedules prompt shift workers to sleep or remain awake at times that are inconsistent with the internal timing mechanism, or clock, that regulates sleep and wakefulness. This results in difficulty initiating or maintaining sleep, or poor quality sleep, otherwise known as insomnia. In attempting to sleep during the daytime after a night of shift work, many shift workers encounter difficulties because they are trying to initiate sleep when their internal clocks are favoring wakefulness. Even employees who do not have SWSD often find they are more fatigued and sleep-deprived than those who sleep regularly at night. In addition, SWSD has been linked to serious health risks and decreased quality of life. According to the New England Journal of Medicine, shift workers appear to be at increased risk for peptic ulcer disease, coronary heart disease, insulin resistance, and metabolic syndrome, as well as for depression, sleepiness-related accidents, and curtailed family and social activities.3

While not all individuals working a “shift work schedule” develop sleep disorders, several factors can contribute to an individual’s predisposition to developing SWSD, including: age, preexistence of an underlying sleep disorder, coping strategies for managing shift work schedules, and the direction in which shift schedule changes occur (clockwise schedules are more tolerated than counterclockwise).4

Treatment Options
Despite the negative impact of excessive daytime sleepiness and insomnia on daytime functioning and quality of life, less than 10% of individuals with these symptoms visit physicians specifically for their sleeping problems.5 However, without eliminating shift work altogether, individuals may continue to suffer from the symptoms of SWSD for as long as their schedule continues to disrupt their sleep cycle. While there is no cure for SWSD, reduction of sleepiness and improvement of vigilance are an important therapeutic imperative for shift workers and recent advances in treatments can help provide relief.

Coping strategies, such as making sure that one allows adequate sleep opportunities, can be valuable. Allowing sufficient time to sleep during the main sleep period of the day is important and may be supplemented by strategic napping, including the use of “recovery naps” taken after a period of sleep loss or “prophylactic naps” taken in anticipation of a period of sleep loss. Adequate sleep and the use of napping strategies to deal with small amounts of sleep loss may be helpful in reducing fatigue-related accidents and injuries.

Options to combat sleepiness include activity during periods of wakefulness, even during breaks, and the use of low-dose caffeine (eg, as in a cup of coffee), which has been shown to improve cognitive performance and the ability to remain awake when compared with placebo among healthy adults during extended enforced time awake.6 Pharmacological treatment with 200 mg of modafinil reduced the extreme sleepiness observed in patients with SWSD and resulted in a small but significant improvement in performance as compared to placebo.7

Securing adequate sleep is a major challenge for all those suffering from a circadian rhythm disorder, as both quality and quantity of sleep are often negatively impacted. Insomnia symptoms include difficulty falling asleep, difficulty sleeping throughout the desired sleep period, awakening too early, or awakening feeling unrefreshed. Lifestyle adjustments may help shift workers, including wearing dark glasses to block out light before attempting to sleep and keeping to the same bed-time and rise-time schedule, even on weekends; and ensuring that times set aside for meals, socialization, and personal activities (eg, shopping, doctor visits) are consistent with the shift work schedule.

Shift workers who suffer from insomnia may benefit from pharmacologic treatment. Those with sleep onset difficulties may benefit from the use of medications that are known to decrease the latency to sleep onset, such as zaleplon and zolpidem. Another recently approved medication for sleep onset insomnia is ramelteon, which has a novel mechanism of action relative to other approved prescription sleep aids.

Those who have both sleep onset and sleep maintenance difficulties, a common problem for shift workers, may benefit from medications that are known to not only help people fall asleep but also reduce the amount of wakefulness during sleep, such as eszopiclone or zolpidem-CR. Given the chronic nature of SWSD, one key consideration is that eszopiclone, ramelteon, and zolpidem-CR lack limitations on duration of use. When using medication for insomnia, it is important to allow adequate sleep opportunity in order to avoid postsleep “hangover” effects. Therefore, shift workers with insomnia should plan sleep opportunities thoughtfully before using medication.

In today’s fast-paced world, poor sleep is a concern for many, perhaps especially those of us who are shift workers. Shift workers with SWSD often experience significant distress and impairment in functioning. Yet, they do not always proactively seek advice from their doctors. The burden of identifying SWSD and its consequences therefore often lies with physicians and other health care professionals. Providing good diagnostic and treatment resources to shift workers may encourage this population to seek medical care. Continued research on the effects of both wake-promoting and sleep-promoting treatments may help to improve the sleep and health of every member of society—24 hours a day, 7 days a week, 365 days a year.

Shift Work and Obstructive Sleep Apnea

By Lena Kauffman

Policymakers and medical professionals alike have long recognized the danger drowsy employees in safety-critical positions, such as pilot, train engineer, or long-haul truck driver, may pose. A majority of these professions are now governed by laws that dictate how many hours in a row a person may work and how many hours off they require between shifts.

However, for researchers like Acacia Aguirre, MD, PhD, medical director at Circadian Technologies Inc, Lexington, Mass, this is only part of the story. While some people thrive as shift workers, others may actually be harming their own health by working shifts. People who work shifts are more likely to smoke, to drink alcohol before going to bed, to exercise less, to be overweight, and to have high blood pressure, Aguirre says. In addition, they may also be at greater risk of obstructive sleep apnea syndrome (OSAS).

In her research for Circadian—a company that helps other companies improve their shift-work policies—Aguirre had found that about 11% of shift workers may have sleep apnea. This is more than twice the national average of 4.058%, which is based on the National Institutes of Health estimate that 12 million Americans may have sleep apnea and the Central Intelligence Agency’s figures for US population.

Circadian’s database included more than 10,000 shift workers at the time of Aguirre’s study on general health. “We estimate that 11% of shift workers may have sleep apnea based on the fact that 14% [of those in the database] get a score indicating that they are at risk of OSAS, and about 70% to 80% of those identified as having possible sleep apnea who have a sleep recording at a hospital end up being diagnosed with it,” she said.

One of the reasons for the higher incidence of OSAS in shiftworkers may be that shift work can lead to a less healthy lifestyle overall, Aguirre theorizes. Work schedules that encourage people to eat at unusual or irregular times can lead to obesity, as can snacking, a strategy some people use to help them stay awake.

In addition, if a shift worker is chronically tired, he or she is unlikely to exercise. In another study Aguirre did, she found that even when people suspected of having sleep apnea and people with morbid obesity (people with a body mass index or BMI of greater than 40) were excluded, 13% of the shift workers Circadian surveyed reported chronic insomnia, 12% excessive sleepiness (according to their Epworth score, a standard sleepiness scale), and 25% reported both chronic insomnia and excessive sleepiness.

While there is no simple cure for the health dangers associated with shift work, companies can help by both paying attention to how long and how often their shift workers are on the job and offer their employees information on how they can reduce the negative side effects of shift work through behavioral changes (eg, decreasing intake of stimulants and depressives, adhering to a regular sleep-wake schedule, reducing stress, and increasing exercise).

“Working shift work does not mean that you have to be miserable or sick,” Aguirre says. “A good work schedule and a healthy lifestyle are key.”

Gary Zammit, PhD, is the founder and current director of the Sleep Disorders Institute at St. Luke’s/Roosevelt Hospital and a clinical associate professor at the Columbia University College of Physicians and Surgeons in New York. He has been the principal investigator on more than 60 clinical trials and has authored more than 80 original publications and two books.

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