Shift Workers and Sleep Problems

In the United States, about 20 to 25 percent of the population that works does some sort of shift work. Surveys show that 60 to 70 percent of shift workers complain of problem sleepiness on the job, or insomnia at home. They sleep on average an hour less per day than workers with day jobs. This can be explained by the diurnality of the human brain. The circadian rhythms naturally prepare people for sleep during nighttime and waking during the day. Even working nights doesn’t fully shift the body’s response in body temperature, and melatonin and cortisol levels in the bloodstream. (Cortisol is a steroid hormone produced by the adrenal glands and important in stress control.)

Additionally, social custom permits sleep during the night more than during the day. Phone calls, general noisiness in a household or neighborhood, and phone calls can make it hard to sleep during the day.

Primary circadian disorders are genetic and/or physiological. Behavioral circadian disorders are caused by people attempt to stay up past their bedtimes. This happens pretty often among people who like to burn the candle at both ends; it can be fun to stay up late on weekends, etc. After a few days with a shifted sleep time, people get used to their new time. However, getting used to the new pattern only happens to some extent. If the natural circadian rhythm clashes with the imposed cycle of the shift work, problems can develop over the long run.

One effect of the shift in sleep patterns is a general stress on the body, and consequent increased risk of disease. Work productivity is also lower. On-the-job accidents are higher when adjusting for the fact that there are fewer people in the workplace. One survey reported that 20% of shift workers reported an accident or “near miss” driving home from work in the previous year.

The disruption of the sleep cycle from shift work influences the physiological functions of the body. Most boidly functions have at least some circadian rhythm, so the confusion created by working at the wrong time for the body can have detrimental effects over the long run. It has long been known that shift work is associated with an increase in heart attack risk. Researchers speculate that the stress of shift work leads to an overall decrease in the body's antioxidant capacity. There are also some suggestions that there is a connection association between metabolic syndrome and shift work.

The connection to cancer is more tenuous. Some studies have suggested shift work increases the risk of breast cancer, although a recent epidemiological study at Ohio State University found no connection between cancer and shift work.

Pregnant women must take special note. Working the night shift increases the chances of delivering the baby past its due date by 35%. Night work also increases the chances of the baby being of low birth rate.

Either with their doctor's cooperation or without, many shift workers use medications to manage this disorder. These include both sleep aids (hypnotics), melatonin, and stimulants (especially caffeine.)

Note that shift work sleep disorder (SWSD) is considered a legitimate disorder and doctors take it seriously. The pharmaceutical company Cephalon has pushed research and awareness of this disorder, perhaps partly because they make a drug that can treat it.

Related: Many police officers have sleep disorders.

"Early to bed, and early to rise,
makes a man healthy, wealthy, and wise." -- Benjamin Franklin, 1758

Resources

Avoiding Drowsy Driving

Countermeasures

Responsibility and the Drowsy Driver

Signs of Drowsiness when Driving

How Well Are You Sleeping? - FDA Consumer Article

Circadian gene helps brain predict mealtime

Sleep less, live longer? - Increased Death Rate Associated
With Sleeping 8 Hours or More

Circadan Rythyms

"And miles to go before I sleep"

(Robert Frost, Stopping by Woods on a Snowy Evening)