Microsleep is a very brief episode of sleep, generally lasting between 1 and 15 seconds. Typically brought on by sleep deprivation, microsleep is a common phenomenon that you’ve most likely experienced where you doze off for mere seconds before jolting back awake. Head nodding, drooping eyelids, and sudden body jerks are all the signs of someone likely experiencing a bout of microsleep.

Though a common phenomenon, microsleep can have dangerous side effects. Parts of the brain shutting down, even for a second, can be very unsafe, especially when doing something requiring our full attention, like driving or operating machinery.

In this post, we’ll discuss the common causes of microsleep, the dangerous side effects, and the symptoms and warning signs. We’ll also share various ways to prevent microsleep and how you can ensure you’re well-rested, even during tiring events like road trips or long workdays.

Symptoms of Microsleep

Microsleep can happen seemingly out of nowhere and without warning. In fact, many people who experience an episode aren’t even aware of it. During microsleep episodes, certain regions of the brain experience “local sleep” while other regions remain awake—this explains why many times we’re not even aware we just experienced microsleep, and instead, believe our minds just wandered off.

Common symptoms, like yawning and heavy eyelids, can seem harmless and non-threatening. However, it’s important to be aware of what microsleep looks and feels like and to take notice if the symptoms become frequent since microsleeping can have dangerous outcomes. Being cognizant of the initial warning signs can prevent you from experiencing an episode, and keep you safe during activities requiring full alertness and attention.

Symptoms of microsleep include:

  • Not responding to information
  • Blank stares
  • Head nodding
  • Drooping eyelids
  • Body jerks
  • Slow blinking
  • Unable to remember the last couple of minutes
  • Wandering thoughts
  • Inability to keep eyes open
  • Excessive yawning
  • Sudden head jerks
  • Constant blinking to stay awake

Causes of Microsleep

Microsleep is caused by a lack of sleep. Any condition or situation depriving you of sleep can be a cause for microsleep. Along with generally not getting enough rest, common contributing factors include sleep disorders, shift work, and monotonous tasks.

Sleep Deprivation

The most common cause of microsleep is not getting enough sleep. When our bodies don’t get enough sleep, we become tired and drowsy. Eventually, when we become sleepy enough, our brain takes over and is able to “shut down” certain areas to recharge. Fighting this need to doze off is when we experience quick lapses between sleep and wakefulness and brief periods of microsleep.

One study revealed that even when these localized areas of the brain “turn off” for a few seconds, it’s possible to remain awake and functioning, albeit poorly. This sleep-like state explains why we often aren’t aware microsleep is happening, or feel as if we’ve “zoned out” for a few seconds.

Sleep Disorders

Anyone struggling with a sleep disorder is at a much higher risk of experiencing microsleep. Sleep disorders, like insomnia, narcolepsy, and sleep apnea, interfere with a good night’s rest, and often lead to sleep deprivation. As we know, a lack of proper sleep is a major contributing factor to microsleep.

Shift Work & Jet Lag

Working through the night and frequently traveling to different time zones can throw off your body’s internal clock since your circadian rhythm uses sunlight and temperature to signal to our brains it’s time to sleep and wake. When this happens, there is an increased likelihood of sleepiness and microsleep occurring.

People who work night shifts, like doctors, truck drivers; frequent flyers, pilots, and flight attendants; and even new parents are very likely to experience a clash in their body’s internal clock due to erratic sleeping and waking hours. The lack of consistency in a day-to-day schedule can lead to a disrupted sleep schedule, ultimately increasing the risk of microsleeps.

Brigham and Women’s Hospital conducted a study analyzing drowsy driving and night shift workers. The study compared the daytime driving of night shift workers after a night of sleep, with their daytime driving after a night of shift work. The findings revealed 37.5 percent of drivers participating in the test drive after working the night shift were involved in a near-crash event. It also showed those same drivers were involved in zero near-crash events after a night of sleep.

Monotonous Tasks

Taking part in repetitive, boring tasks can make us sleepy because they don’t engage our brains. Monotonous tasks include things like long drives on open roads, stationary work, riding in a train, or sitting for long periods of time.

A 2012 study revealed the effects long-lasting disengaging activities have on our brains. During the study, twenty rested participants used a joystick to track a moving target on a computer screen for 50 minutes. Researchers monitored brain and eye activity and found participants, on average, experienced 79 episodes of microsleep, lasting up to six seconds each time. (And these participants were well-rested, so researchers can only assume tired participants will experience microsleeping far more.)

Dangers of Microsleep

Nodding off can be embarrassing or inconvenient, but more so it can be very dangerous. Experiencing an episode of microsleep while driving or operating machinery, for example, can lead to injury or death. Frequent occurrences of microsleep can also have long-term cognitive effects.

Drowsy Driving

Perhaps one of the most common dangers of microsleep is drowsy driving. Nodding off at the wheel for even one second can have catastrophic consequences. According to the AAA Foundation, 16.5 percent of fatal accidents on the nation’s roadways involve a drowsy driver.

It doesn’t take dozing off for drowsy driving to become dangerous. Sleep deprivation alone can be a serious safety hazard. It can impair judgment and reduce reaction time, leading to an accident.

According to the CDC, those most at risk of drowsy driving are shift workers, commercial truck and bus drivers, people with untreated sleep disorders or who take sleep medications, and anyone who simply doesn’t get enough sleep.

AAA’s tips to prevent drowsy driving include:

  • Don’t drive when you’re sleepy or tired
  • Before a long road trip, get enough sleep
  • Travel with a passenger
  • Take a power nap
  • Schedule a break

Workplace Accidents

Accidents in the workplace are another major danger of microsleep, especially in certain industries, like aviation or medicine.

Fatigue among pilots, aircrews, and air traffic controllers, for example, have been the cause of multiple aviation accidents in the past. Working frequent night shifts is common among flight crews and can lead to exhaustion and mistakes. The crash of Air France Flight 447 was due to sleep-deprived pilots.

Doctors, nurses, and other medical-related professions are also at high risk for fatigue-related accidents. These occupations can require making critical decisions and maintaining full alertness. However, working long overnight shifts is common in the medical field, and a lack of sleep can lead to fatal mishaps for patients. In a recent survey, nearly one-fifth of nurses working permanent night shifts reported struggling to stay awake to take care of a patient at least once in the month prior. Another survey showed 35.3 percent of nurses working rotating shifts fell asleep at least once a week during the night shift.

Aside from causing physical harm to yourself or someone else, sleepiness also has a financial impact. An estimated $18 billion is lost each year due to fatigue-related problems in America. Whether you’re an airline pilot or an office assistant, sleep deprivation is a serious problem affecting our decision-making skills, judgment, and focus.

Cognitive Side Effects

Frequent microsleeps can affect short-term memory, alertness, and lapses in attention. Moreover, sleep deprivation on its own can have adverse effects on our mood. It can lead to increased depression, increased irritability, and feeling more stressed.

Microsleep Prevention and Precautions

The best cure for microsleep is simply to practice good sleep hygiene and get enough quality shut-eye. Even when tiredness is unavoidable on some days, there are various things you can do to ensure you never fall victim to an episode of microsleep.


The best way to prevent an episode of microsleep is to get plenty of rest and avoid bad sleep habits. Enhance sleep by keeping these tips in mind:

  • Maintain a regular sleep schedule
  • Avoid electronics prior to bedtime
  • Create a relaxing bedroom environment
  • Exercise regularly
  • Limit caffeine consumption


Getting enough quality sleep is the best prevention for microsleep. However, bouts of sleepiness are impossible to avoid all the time. Follow these precautions to keep you and others safe during an exceptionally tiring day:

  • Don’t participate in potentially dangerous activities when you’re tired
  • Listen to your body; rest when you feel tired
  • Schedule regular naps during a long day of work or road trip
  • Get plenty of sleep before a road trip
  • Keep moving
  • Talk to other people


How can you prevent microsleep when driving?

The best way to prevent microsleep while driving is to keep your mind engaged. Listening to an interesting podcast or chatting with another passenger in the car can all help keep your brain active.

It’s important to note, you should only operate a vehicle when you feel alert. If you find yourself drifting out of your lane, missing turns or exits, or experiencing heavy eyelids and yawning, you need to pull over and rest.

How long does microsleep last?

Microsleep typically lasts just a few seconds but can last up to 30 seconds. Episodes are often so short in duration that you may not even realize it’s happening.

While microsleep can be harmless in some situations, like while watching TV on the couch, it can be very dangerous in other instances. Operating machinery or driving are a couple of examples when a one-second episode of microsleep can be fatal.

How long can you go without sleep before hallucinating?

There are only a few recent studies on prolonged sleep deprivation because it’s now considered unethical. However, past studies show after 24 hours of no sleep, symptoms included perceptual distortions and temporal disorientation. Complex hallucinations and disordered thinking were shown to begin after 48 to 90 hours of sleep deprivation. By the third day without sleep, hallucinations were shown to be present for three senses including visual, auditory, and touch.

Why do I keep nodding off to sleep?

If you find yourself nodding off to sleep, it means you’re sleep-deprived and need rest. When our bodies reach a certain level of exhaustion, our brains take over and “force” our bodies to rest, even for just a second. When this happens, we usually experience heavy, drooping eyelids, nodding head, body jerks, and constant blinking to try and stay awake.

Are 20-minute naps good for you?

Short naps ranging from 10 to 20 minutes are ideal for boosting energy and alertness. Often referred to as a power nap, these short bits of rest provide immediate benefits like improving performance levels and decreasing feelings of sleepiness.

During a power nap, we stay in the first two stages of non-rapid eye movement. These stages of sleep are the lightest of all the stages, making them the easiest to wake from. Naps any longer than 20 minutes will send your body into the third and fourth stages of sleep, when we experience deep sleep. Waking from these stages can be difficult and can make you feel groggy and disoriented upon waking.


Microsleep is a common phenomenon in our world, but that doesn’t mean it’s not dangerous. Nodding off for a few seconds due to extreme fatigue is something we’ve all experienced and it’s vital we do everything we can to prevent it. Getting plenty of quality rest and being vigilant of the warning signs is the best way to combat the effects of sleep deprivation and ultimately avoid episodes of microsleep. While we certainly can’t escape being tired every day, prioritizing a good night’s sleep is the first step to staying rested and safe.

This article is for informational purposes and should not replace advice from your doctor or other medical professional.