The Problem

One quarter of the work force in industrialized countries perform some sort of shift work.  Millions of Americans are considered shift workers, including doctors and nurses, pilots, bridge-builders, police officers, customer service representatives, commercial drivers, and others.

Sleepiness is common among shift workers, especially during the night shift:

• 80% of shift workers feel tired during their night shift.
• 60% believe they doze off at work about once per week.
• 20% fall asleep on the night shift.
• Sleepiness in shift workers is similar to that seen in primary sleep disorders, such as sleep apnea or narcolepsy.

Reasons for sleepiness in shift workers include:

• Shift workers often do not get enough sleep before their shifts.
• Sleep after the shift is usually shortened (by an average of one-third).
• Even if adequate in duration, sleep near shifts is usually fragmented.
• The day-night cycle (circadian rhythm) of the brain and the body may get disrupted when working different shifts.
• Shift workers may have other primary sleep disorders independent of their work schedule.

Consequences of sleepiness can be hazardous to the worker’s health and may cause decreased work performance:

• Near-crashes when driving after night shifts are common.
• Shift workers are at increased risk for a variety of chronic illnesses such as cardiovascular and gastrointestinal diseases.
• Shift workers often complain of insomnia, disrupted sleep schedules, reduced performance, difficulties with personal relationships, and irritability/depressed mood.
• Sleepiness effects are similar to that of moderate alcohol consumption.
• Several disasters, such as the nuclear meltdown at Chernobyl and the Challenger space shuttle disaster, have been attributed to poor performance related to shift work.
• Caffeine is a stimulant that starts working 30 minutes after consumption.  Its effect peaks at 2 hours and lasts for about 5 hours.  Problems associated with its use include disruption of subsequent sleep, tolerance, and a diuretic effect that may be dehydrating or becomes a nuisance.

The Solutions

There are several strategies that may help a worker cope with the sleep-wake cycle disturbances resulting from working different shifts.  If your sleep-wake cycle does not adjust perfectly with your work schedule, it may be useful to control your shift schedule and your environment, instead.

• The number of shifts worked in a row has not been shown to be an important factor in sleepiness.
• Direction in which shifts rotate may be important.  Shifts that rotate forward are better tolerated  (see Table 1).
• Duration of shifts contribute to the ill effects, the shorter shifts being better tolerated.
• Exposure to bright light (more than 2000 lux, such as the light of 5 standard fluorescent tube bulbs) increases alertness by inhibiting the secretion of a natural hormone called melatonin.  Melatonin promotes sleep and its secretion increases in darkness.  It is best to maximize light exposure early in a shift and avoid it 6 hours before bed time.
• Strategic napping is one way of getting enough sleep before a shift, and during the shift (if feasible).  A nap of no longer than 30 minute can restore functionality. Longer naps tend to lead to sleep inertia or grogginess with awakening.
• Phase shift is another way to manage rotating shifts, as one may intentionally move bed time towards the anticipated shift end time.  This can be done if there are a few days off between shift switches.

In some cases, your doctor may prescribe medications such as the following:

• Sedatives (hypnotics) may be used to improve sleep after a shift, but their effect on shift work is unknown.
• Melatonin (sleep rhythm aid): may be used to modify the sleep phase to a new sleep schedule, especially when combined with strategic light and darkness exposure.
• Modafinil (Provigil®): has been shown to improve vigilance in night shift workers, but to a limited extent.

Theses treatments are not well studied and a physician should supervise their use.

Tips for Coping with Shift Work:

• Keep to the same sleep schedule when your shifts are constant, even on non-work days.
• Have as much exposure to bright light as possible when you need to be alert, and avoid light exposure in the morning after night shift.
• Protect your sleep by eliminating noise and light from your sleep environment (use eye masks and ear plugs).
• Avoid using caffeine close to bedtime.
• Avoid drinking alcohol since it disrupts sleep, even though it may seem to help in falling asleep, initially.
• Nap before work, and if possible on breaks during the shift since any sleep is better than no sleep.
• If you still have problems, contact your physician, or a Sleep Specialist.

Table 1: Shows weekly schedule of a shift worker where the shifts (shaded areas) proceed along with the clock: 7 am to 3 pm, followed by 3 pm to 11 pm, followed by 11 pm to 7 am, and so on.  

Table 2: Shows the weekly schedule of a shift worker where the shifts proceed against the clock: 3 pm to 11 pm, followed by 7 am to 3 pm followed by 11 pm to 7 am, and so on.  The top shift schedule is better tolerated than the bottom one.

To schedule an appointment, call MetroHealth's Center for Sleep Medicine at (216) 778-5985 .

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