Microsleep is a short burst of sleep lasting just a few seconds. A person cannot control microsleep episodes, and some people may even appear to be awake during them.

These dangerous sleep episodes are a major risk factor for vehicle accidents and other errors. They occur as the body’s response to sleep deprivation. When a person is tired, the body reduces alertness, and this can lead to microsleep.

Keep reading to learn more about the causes of microsleep, its risks, and how to prevent it.

Person holding their face, feeling very tired and battling microsleep.Share on Pinterest
Tnia Cabral/EyeEm/Getty Images

Microsleep is the body’s response to severe sleep deprivation or consistently disrupted sleep. People who work night shifts, those with sleep apnea, and individuals with insomnia that seriously disrupts sleep may fall asleep for brief periods during the day.

Microsleep can happen at any time, including while engaging in demanding activities such as driving.

One preliminary study in animals suggests that microsleep can shut down individual portions of the brain. When this happens, a person may appear to be awake or continue doing their activity but be unable to process information or understand what is happening.

Microsleep occurs when the body is very sleep deprived. No single medical condition causes all episodes of microsleep, but any medical condition that affects sleep can cause microsleep.

As fatigue increases, so does the risk of experiencing a microsleep episode. One 2020 study, for example, found that having episodes of microsleep indicates more severe sleep deprivation in people with obstructive sleep apnea.

Some risk factors for microsleep include:

  • working night shifts
  • having shift work sleep disorder due to working many night shifts or having an unpredictable work schedule
  • having sleep apnea (obstructive, central, or mixed)
  • having severe insomnia
  • using drugs that affect sleep

People with narcolepsy, which is a medical condition that disrupts the brain’s sleep-wake cycles, may also experience microsleep episodes.

People with narcolepsy may suddenly fall into a deep sleep for extended periods of time.

People experiencing microsleep episodes may not notice any obvious symptoms. Or, they may notice:

  • sudden lapses in attention
  • suddenly not remembering what they were doing
  • confusion during complex tasks such as driving
  • feeling zoned out
  • forgetting the last few moments

Bystanders might notice that a person looks awake but does not seem fully responsive. People might not remember snippets of conversation, or they might need to be reminded of what they were doing just a few seconds before.

People who work unusual hours, have sleep apnea, or experience severe sleep deprivation should consider the possibility that they may be experiencing microsleep episodes — particularly if they often feel tired or confused during the day.

A sleep study may be able to detect episodes of microsleep. A doctor can also detect microsleep using electroencephalography, which measures brain waves.

Microsleep is the body’s response to severe sleep deprivation. When it happens, a person is so tired that they have lost control over their ability to control falling asleep.

This greatly increases their risk of the following:

  • vehicle accidents
  • errors at work, such as medical errors by healthcare professionals who work long hours
  • confusion during the day
  • relationship issues, if a person has microsleep episodes that affect their ability to relate to or communicate with loved ones
  • harming their children, if they fall asleep while caring for their children

Some occupations that require unpredictable or long shifts also require paying very close attention to avoid potentially lethal errors. Healthcare professionals, truck drivers, pilots, and many other professionals may sustain catastrophic injuries or endanger others if they fall asleep on the job — even for a moment.

Even when a person is not having a microsleep episode, severe fatigue can affect performance. For example, drivers who go longer than 20 hours without sleep may drive as poorly as someone who has consumed alcohol. So, both microsleep and the fatigue that causes it are significant health risk factors.

Some vehicles now offer crash avoidance alerts to prevent exhausted drivers from falling asleep at the wheel.

Preventing microsleep requires a person to address the cause of their fatigue. This might mean changing to more consistent work shifts, getting more sleep at night, or seeking treatment for sleep apnea.

Some potential treatment options include:

  • Insomnia treatment: This may include:
    • undergoing therapy to help a person manage nighttime anxiety
    • making changes in sleep habits, such as going to bed at the same time each night
    • in some cases, taking medication to help a person fall asleep
  • Medication to improve daytime sleepiness: Some medications can help a person feel more alert during the day. The Food and Drug Administration (FDA) have approved drugs such as modafinil and armodafinil for excessive sleepiness associated with shift work sleep disorder.
  • Changes in employment practices: Jobs that require a person to go very long periods of time without sleep may need to change their policies to keep employees safe.

Get more tips for better quality sleep here.

A person should contact a doctor if they think that they experience microsleep episodes or if they have any medical conditions that might increase the risk of microsleep.

Contact a doctor for:

  • intense daytime sleepiness
  • frequent nighttime waking
  • consistently not sleeping, not getting enough sleep, or getting sleep only in short bursts
  • problems with inattention or confusion during the day
  • suddenly feeling confused during conversations or other daily activities

Microsleep is a dangerous phenomenon that warns of severe sleep deprivation.

It can endanger fatigued people as well as those around them. It is not something that a person should aspire to or train to do.

Instead, a person who experiences microsleep episodes must seek professional help.