What is Microsleep?


If you’ve ever tried to fight your body’s urge to fall asleep, you may have experienced microsleep. Microsleep is a short, involuntary episode of sleep (1). The most common symptoms (2) of a microsleep episode are:

  • Head nodding
  • Drooping eyes
  • Slow closing of the eyes

Microsleeps last from 1 to 15 seconds (3). Episodes can occur when performing a task that demands constant focus and attention, such as driving.

Healthy sleep usually involves cycling through a series of sleep stages (4), beginning with light sleep and progressing into deeper stages of sleep. Microsleep doesn’t follow the same pattern as normal sleep. Instead, microsleep represents a state somewhere in between wakefulness and regular sleep.

What Causes Microsleep?

The major underlying cause of microsleep is sleep deprivation or a lack of sleep. Insufficient sleep is common in the United States. More than one-third of adults (5) report getting less than the recommended 7 to 8 hours of sleep each night.

However, we don’t all respond to sleep loss in the same way. If you’re someone who always gets plenty of high-quality sleep, you’re more likely to have a microsleep episode after just one night of poor sleep (6) than someone who regularly experiences insufficient sleep.

Below are some situations that can cause sleep loss and may increase your risk for microsleep.

Sleep Disorders

Sleep deprivation and microsleeps are sometimes secondary symptoms of a sleep disorder. Many sleep disorders are associated with (7) fragmented sleep, poor sleep quality, and increased daytime sleepiness, including:

Shift Work

Certain professions rely on extended or overnight shifts, also called shift work. Shift workers often experience shorter sleep or lower quality sleep (8). Some examples of professions that rely on shift workers include:

Pulling an All-Nighter

College students sometimes resort to staying up all night to finish an assignment or cram for an exam. And drivers on a long road trip may continue late into the night to cover more ground and make good time. Feeling very drowsy after pulling an all-nighter could make you prone to microsleeps.

When Does Microsleep Occur?

You may be most likely to experience microsleep in the afternoon (9), during a period that is referred to as the afternoon slump. The hours in the afternoon correspond to fluctuations in your circadian rhythm when energy levels and alertness are naturally low.

What Are the Risks of Microsleep?

Under most circumstances, nodding off from microsleep won’t have any major consequences. But in certain situations, the possibility of a microsleep episode can carry significant risks.

It might come as no surprise that sleepiness and microsleep impairs your ability to drive safely. Even a few seconds of microsleep can cause an accident. In fact, driving while drowsy accounted for nearly 100,000 traffic accidents in 2017 (10). Microsleep can also lead to accidents in the workplace (11).

Additionally, if you experience sleep loss on a regular basis, it can affect your overall health. Chronic sleep deprivation can lead to health effects such as:

How Do Doctors Diagnose Microsleep?

When a microsleep occurs, your brain undergoes distinct changes in neural activity. There are several ways for researchers to detect these changes. These include tests to measure brain activity such as an electroencephalogram or EEG and a functional MRI as well as behavioral tests including reaction time tests and tests to measure eye blinking and movement.

It’s important to see a doctor if you have concerns about sleep loss, including microsleep. Your doctor may gather information on your symptoms and evaluate you for possible causes (14) of sleep issues, such as health conditions and sleep disorders.

How Can You Treat or Prevent Microsleep?

Treatment for sleep deprivation and microsleeps depends on the underlying cause. For example, people who experience microsleep related to sleep apnea often see improvement of daytime sleepiness (15) after beginning treatment with continuous positive airway pressure (also called CPAP) therapy at night.

If you aren’t suffering from an underlying sleep disorder or other health condition that affects sleep, you can prevent microsleep by focusing on lifestyle adjustments. First and foremost, make sure you’re getting enough sleep. For the average adult, this means getting at least seven hours of sleep every night.

If you struggle to get a full night’s sleep, try taking short naps during the day to stay alert. Avoid performing important tasks like driving or using heavy machinery at times when you normally experience sleepiness like the afternoon or late at night.

Improving your sleep quality may save you from falling asleep at the wrong time, but it also has significant implications for your overall health. Getting more sleep not only reduces your risk of getting into an accident, it also boosts your mood, energy levels, focus, and reduces your risk for chronic disease.


+ 15 Sources
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  2. 2. Accessed on March 11, 2021.https://pubmed.ncbi.nlm.nih.gov/23008180/
  3. 3. Accessed on March 11, 2021.https://pubmed.ncbi.nlm.nih.gov/32038155/
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  5. 5. Accessed on March 11, 2021.https://www.cdc.gov/sleep/data_statistics.html
  6. 6. Accessed on March 11, 2021.https://pubmed.ncbi.nlm.nih.gov/23998288/
  7. 7. Accessed on March 11, 2021.https://pubmed.ncbi.nlm.nih.gov/32809555/
  8. 8. Accessed on March 11, 2021.https://www.cdc.gov/niosh/work-hour-training-for-nurses/longhours/mod3/02.html
  9. 9. Accessed on March 11, 2021.https://pubmed.ncbi.nlm.nih.gov/20090864/
  10. 10. Accessed on March 11, 2021.https://www.nhtsa.gov/risky-driving/drowsy-driving
  11. 11. Accessed on March 11, 2021.https://pubmed.ncbi.nlm.nih.gov/19561846/
  12. 12. Accessed on March 11, 2021.https://pubmed.ncbi.nlm.nih.gov/27467177/
  13. 13. Accessed on March 11, 2021.https://pubmed.ncbi.nlm.nih.gov/31613456/
  14. 14. Accessed on March 11, 2021.https://www.ncbi.nlm.nih.gov/books/NBK547676/
  15. 15. Accessed on March 11, 2021.https://medlineplus.gov/ency/article/001916.htm

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