1. How Does Shift Work Affect Sleep?
2. What Are Some of the Consequences of Sleepiness During Shift Work?
3. What are Some Things I Can Do to Sleep Better?
4. What Are Some Tips for Coping with Shift Work?
5. What Are Some Examples of Shift Work Schedules?

How Does Shift Work Affect Sleep?

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.

As the statistics below suggest, 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:

• Not getting enough sleep before work
• 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

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What Are Some of the Consequences of Sleepiness During Shift Work?

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.

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What are Some Things I Can Do to Sleep Better?

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.

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What Are Some 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.  

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What Are Some Examples of Shift Work Schedules?

Table 1 shows the six-day work week of a shift worker where the shifts proceed along with the clock: 7 a.m. to 3 p.m., followed by 3 to 11 p.m., followed by 11 p.m. to 7 a.m., and so on.  

Table 2 shows the six-day work week of a shift worker where the shifts proceed against the clock: 3 to 11 p.m., followed by 7 a.m. to 3 p.m. followed by 11 p.m. to 7 a.m., and so on. The shift schedule in Table 1 is better tolerated than the one in Table 2.

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