THERE’S A GOOD CHANCE you’ve experienced a “microsleep” episode without even realizing it.
Although it’s most common in people suffering from sleep deprivation, microsleep can happen to anyone. Microsleep, also known as micro sleep or micro naps, is a brief period in which the person loses consciousness, going into a sleep-like state. It can last anywhere from a fraction of a second to 30 seconds or more, with an average duration of four to five seconds. Essentially, you “nod off” or lose focus before snapping back to wakefulness. Many people think they’ve just “zoned out” when in reality, they have experienced micro sleep. Micro sleep is often an indicator of insufficient sleep or poor sleep quality, and it can have dire consequences.

Why Does It Happen?

Inadequate sleep is more widespread than most people realize: according to a 2009 study, up to 45 percent of adults report having unintentionally fallen asleep, and more than seven percent of respondents ages 25 to 35 reported that they had fallen asleep while driving.

Those are among the reasons that inadequate sleep has been deemed a public health crisis by the CDC, so researchers are invested in learning more about the causes of sleep disorders, like micro sleep, as well as how to prevent them.

Because sleep is a biological necessity, the brain will find some way to compensate if it’s not getting enough. One way it does this is through “forced naps,” or microsleep. Researchers found reduced brain wave activity, consistent with what occurs during normal sleep, in the thalamus of sleep-deprived volunteers experiencing microsleep episodes.

The Leading Cause of Microsleep

Micro sleep and other manifestations of excessive daytime sleepiness are almost always indicators of an underlying condition. The leading culprit is sleep apnea, which affects up to 15 million people. Sleep apnea greatly reduces sleep quality by causing dozens to hundreds of brief sleep interruptions each night. People with sleep apnea stop breathing for short periods, causing them to awaken abruptly. Most people quickly fall asleep after each episode and may not even realize they’ve awoken. They believe they’re getting adequate sleep each night, but in reality, their sleep cycles are severely disrupted. The other leading cause of micro sleep is insomnia, which itself is usually due to an underlying medical cause.

When Microsleep Is Dangerous

Microsleep can occur during monotonous activities, like listening to a boring lecture, in which case it’s relatively harmless. However, this manifestation of drowsiness has a dark side. Microsleep is often the culprit behind sleep-related car accidents and it accounts for two to three percent of all fatal car accidents. Microsleep has also been implicated in a range of serious work-related accidents; it may have been the cause behind the 2003 Waterfall train disaster, the 2009 AirFrance Flight 447 crash, and even the Chernobyl nuclear reactor accident in 1986.

What To Do About It

If you find yourself feeling drowsy behind the wheel, get off the road as soon as possible. Pull over for a brief nap (in a safe location such as a police-patrolled rest stop) or ask someone else to drive if that’s an option. Caffeine and energy drinks offer a possible short-term fix for drowsiness, but don’t rely on them for long periods of time. The National Sleep Foundation offers several other drowsy driving tips plus information on how to tell if you’re too tired to drive.

If you suffer from microsleep or other types of daytime sleepiness, see your doctor to learn more about potential underlying causes, such as insomnia and sleep apnea. Treating the disorder that’s causing your daytime sleepiness will allow you to get a healthy amount of quality sleep each night, eventually eliminating your microsleep problem.