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What to Know About Microsleep

Medically Reviewed by Dan Brennan, MD on June 11, 2021

Perhaps you are watching a movie and jerk yourself awake multiple times. Maybe you are driving at night and awaken when your car crosses a rumble strip. In both cases, you have experienced microsleep. Microsleep can be dangerous or just annoying, depending on when it happens.

What Is Microsleep?

Microsleep refers to episodes of sleep lasting less than 30 seconds. Often, you aren't aware of them. You may have multiple episodes of microsleep close together, as you try — and fail — to stay awake

Often in microsleep, your brain flips rapidly between being asleep and being awake. Each sleep period lasts only a few seconds. A period of sleep needs to last at least a minute before the brain can register it.

You may have experienced microsleep if: 

  • You're awakened by body jerks or your head falling forward
  • You find yourself yawning or blinking excessively
  • You aren't aware of something that just happened
  • You have trouble processing information

Dangers of Microsleep While Driving

If you are home on your sofa, microsleep may be an irritation, but it's unlikely to be dangerous. In other situations, microsleep can pose a threat to yourself and others. Driving while experiencing microsleep is a common hazard.

The National Highway Traffic Safety Administration estimates that up to 6,000 fatal crashes each year may be linked to drowsy drivers. In one survey, 4% of drivers said they had fallen asleep while driving at least once in the past 30 days. 

Microsleeps are especially dangerous for drivers because of the short time it takes to make a serious mistake at the wheel. If you doze for 3 seconds while going 60 miles per hour, you can travel 300 feet in the wrong direction. This can put you off the road or into an opposing lane of traffic. 

Other Dangers of Microsleep

‌Public safety is threatened when certain workers experience microsleep. Microsleep can be especially serious if you work as any of the following:

  • Pilot
  • Air traffic controller
  • Truck driver
  • Locomotive driver
  • Process worker in a plant or refinery

The medical field is another field where sleep deprivation can have a serious impact. Several studies have shown that needlesticks and injuries with sharp instruments happen more often when medical workers are on night shift, extended hours, or mandatory overtime. Other medical errors may increase, as well.

Microsleep and Sleep Deprivation

Sleep deprivation is the main cause of microsleep. One study found that 20% of those surveyed needed 90 minutes more sleep per night than they were getting. Shift work and long hours at work are part of the problem. Round-the-clock digital access is another problem.

You don't have to have a pattern of sleep deprivation to be affected. One study found that just one night of restricted sleep (less than 4 hours) resulted in an increase in microsleep. Also, those who have regular patterns of sleep are more likely to have microsleep episodes when they lose sleep.

Other Causes of Microsleep

Poor quality of sleep may also result in microsleep. Poor sleep can stem from physical and mental conditions, including:

The use of alcohol and certain medications can lead to episodes of microsleep. Antihistamines are one commonly used medicine that can cause sleepiness.

Prevention of Microsleep

Short-term fixes for sleepiness can cut down on microsleep. Try these tips when you feel drowsy:

  • Change what you are doing. It only takes about half an hour for monotony to affect your alertness. A break to get up and move around is especially helpful.
  • Take apower nap. Sometimes you can't work your way through your sleepiness. Sleeping for 20 minutes or so can help. Set an alarm if you have trouble waking up.
  • Talk to someone. Conversation wakes up the brain cells. Also, talking speeds up breathing and pumps extra oxygen into the bloodstream.
  • Have some caffeine. Allow about 30 minutes for it to kick in. And try not to consume it too close to bedtime.

For a more long-term fix, work on improving your sleep habits. Plan to spend 8 hours in bed, which will usually result in 7 hours of sleep. That's enough sleep for most adults. Be sure to get some exercise during the day. Limit screen use near bedtime. Avoid heavy meals, caffeine, nicotine, and alcohol within several hours of bedtime.

WebMD Medical Reference

Sources

SOURCES:

Centers for Disease Control and Prevention: "Drowsy Driving: Asleep at the Wheel," "NIOSH Training for Nurses on Shift Work and Long Work Hours."

Chronobiology International: "Efficient and Regular Patterns of Nighttime Sleep are Related to Increased Vulnerability to Microsleeps Following a Single Night of Sleep Restriction."

Cleveland Clinic: "What You Should Know About Microsleep."

Hanson, J., Huecker, M. Sleep Deprivation, StatPearls Publishing, 2021.

Human Brain Mapping: "Losing the struggle to stay awake: Divergent thalamic and cortical activity during microsleeps."

Mayo Clinic: "Sleep tips: 6 steps to better sleep."

Sleep Advisor: "Microsleeps and Micro Naps: Understanding the Symptoms and Causes."

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