Most people who work shifts will experience some difficulty with these symptoms—for example waking up after fewer than 7-9 hours of sleep or feeling drowsy while on the job. For people with shift work disorder, however, this is an ongoing problem that continually causes symptoms and starts to interfere with work or family life.
Shift work disorder can be caused by night shifts, rotating shifts, or even an early morning shift. It can cause chronic sleep deprivation, in which a person never catches up on needed sleep and carries a significant “sleep debt” with them. This kind of chronic loss of sleep has serious implications for health, productivity, and safety.
Many shift workers struggle with excessive sleepiness during the hours in which they’re supposed to be at work, with family, or during leisure activities. The symptom of excessive sleepiness means that you feel as though you’re fighting sleep, or have the sensation that you’re going to nod off during work or social time. Excessive sleepiness goes beyond the natural “dip” in alertness that many people feel a certain points in the day—it’s a relatively constant symptom that interferes with your ability to work, study, or engage in social activities.
People who are very sleepy can actually experience something called a “microsleep,” which is a brief occurrence of falling asleep. A microsleep is involuntary and lasts just a few seconds. Of course, falling asleep on the job can be very dangerous, harmful to your productivity or competence at work, and also upsetting for you and your family and friends if it happens regularly.
For people who experience excessive sleepiness or microsleeps, proper napping during shifts or off hours may be very helpful.