Sleep Inertia: Getting Past the Grogginess

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All of us have had times where we wake up feeling groggy, out of it, and a bit slow on the uptake. For many of us, this is a daily occurrence. This is known as sleep inertia, which is defined as a temporary period after waking up from sleep where you feel disoriented, moody, and experience slower reaction times and mild memory lapses.

For most people, sleep inertia passes quickly and is more of a nuisance than anything else. But it can be more serious for others, especially people who are sleep deprived, do shift work, or who experience sleep disorders. Here, we’ll look at what causes sleep inertia, its symptoms, and how to treat it.

Is It Normal to Have Sleep Inertia?

It’s extremely common to experience sleep inertia. Although some people wake up bright and refreshed in the morning, almost all of us have had times where we wake up feeling sluggish and a bit confused. For many of us, this feeling happens most mornings, even if it passes within a short time frame.

According to Sleep Medicine Review, sleep inertia is common in the general population. It’s most common among adolescents, with 42% of them experiencing it. In general, it becomes less frequent the older a person gets, and seems to strike men and women at equal rates.

How Long Does Sleep Inertia Last?

Most people find that sleep inertia is a fairly short-lived experience. The CDC reports that it lasts an average of 30 minutes in most cases. But it’s not uncommon for it to last up to an hour. In more extreme cases, sleep inertia may last as long as two hours. Longer periods of sleep inertia usually correspond with someone being sleep deprived.

Why Do I Never Wake Up Feeling Rested?

It’s common for people to wake up feeling groggy sometimes, though this usually passes in 30 minutes or so. If this is a constant occurrence for you, consider making getting enough sleep a priority, as sleep deprivation is a frequent cause of sleeping unrested upon waking. If you need further assistance, connect with a healthcare provider or mental health professional for support.

Symptoms of Sleep Inertia

Everyone experiences sleep inertia a little differently and with varying intensity, but the main characteristic of sleep inertia is feeling slow, groggy, and disoriented.

Other symptoms may include:

  • Moodiness
  • Decline in reaction time
  • Slower cognitive functioning
  • Decreased short-term memory
  • Reduced performance and ability to complete tasks
  • A deep desire to go back to sleep
  • Diminished vigilance and ability to pay attention
  • Poor decision making skills

For most of us, these symptoms simply mean that we are less functional first thing in the morning. But for people who need to wake up and do high-stakes type of work—such as operating heavy machinery, military or police work, or working in healthcare—experiencing intense sleep inertia can increase the chances of accidents and can be hazardous.

Why Does Sleep Inertia Happen?

At this point, experts aren’t sure what causes sleep inertia. But it’s considered a relatively normal aspect of sleep, and is thought to be part of the transitionary period between sleep and waking. Sleep inertia seems to be most pronounced after your biological sleep period—i.e., after your nighttime sleep.

Although it’s normal to experience sleep inertia, it exists on a spectrum, where it becomes more pronounced in certain circumstances and among certain individuals. As such, there are some risk factors that affect the intensity and duration of sleep inertia. For example:

  • People who do shift work or who work at night often experience worse sleep inertia
  • People who are experiencing sleep deprivation are more prone to it
  • Night owls” may experience more sleep inertia on days that they need to wake up early for work
  • Younger people, especially teens, experience more intense sleep inertia
  • People who experience mood disorders, including unipolar depression and bipolar depression, may experience more challenging sleep inertia
  • Some people find that napping actually increases the intensity of sleep inertia more than nighttime sleep

Why Am I Groggy After a Nap?

Many people experience worse sleep inertia when they are woken from a deep sleep. This is also likely why some people are more prone to sleep inertia while napping, particularly if they have taken a longer nap later. Reducing your nap duration to 30 minutes can help reduce the likelihood that you will go into a deep sleep and have trouble feeling alert after your nap.

What Is Severe Sleep Inertia?

For most people, sleep inertia is primarily an inconvenience and discomfort. It’s common for sleep inertia to get worse when you are sleep deprived or when your sleep schedule is irregular. But for some people, sleep inertia is debilitating. If you are experiencing severe sleep inertia, it’s possible that you are actually experiencing a sleep disorder.

Extreme sleep inertia is associated with a sleep disorder called hypersomnolence disorder (“sleep drunkenness”), which is characterized by excessive sleepiness, even after getting 7 or 8 hours of sleep.

Besides intense sleep inertia, other symptom of hypersomnolence disorder include:

  • Falling asleep unintentionally during the day, such as while watching TV
  • Sleeping over 9 hours a night and still feeling exhausted
  • Difficulty staying awake in the morning or after being woken up suddenly

To be diagnosed with hypersomnolence disorder, you need to experience these symptoms at least three days a week for at least three months. Please connect with a sleep specialist if you have any signs of hypersomnolence disorder or if your sleep inertia is severe and making it difficult to function.

How Do I Get Rid of Sleep Inertia?

If your sleep inertia is mild, and seems to go away within 30-60 minutes, there is nothing you need to change. You are normal, and you are far from alone. But if your sleep inertia feels especially challenging, there are some things you can try to lessen it or make it go away.

First, you can tackle some of the potential causes of more pronounced sleep inertia:

  • If you are sleep deprived, do you best to make sleep a priority, going to sleep at a reasonable time each night, and practicing good sleep hygiene (dimming the lights, limiting screen time before bed, engaging in a relaxing ritual, like meditation)
  • If your work schedule if impacting your ability to function in the morning or at work, contact your supervisor and ask for an different schedule; alternatively, consider switching jobs
  • If you are someone who is experiencing a mental health challenge or crisis, consider speaking to a therapist, and share the sleep inertia symptoms you are experiencing
  • If you are experiencing severe sleep inertia, connect with an MD who specializes in sleep disorders, or visit your primary care provider for a referral

In addition to addressing the root cause of your sleep inertia, there are a couple of lifestyle changes to consider that may help reduce your sleep inertia symptoms or severity. Here are some options:

  • 100mg of caffeine upon waking can decrease sleep inertia
  • Splashing water on your face soon after waking can reduce symptoms
  • As unpleasant as it may seem, exposing yourself to bright light in the morning can reduce sleep inertia
  • Using a noise machine while sleeping may reduce sleep inertia
  • For some people, making sure to eat breakfast early on can reduce sleep inertia
  • Taking a shower soon after waking decreases sleep inertia for some people

Does drinking coffee help with sleep inertia?

If you tend to feel especially groggy when taking a nap, you might consider trying a “coffee nap,” which is when you consume caffeine before your nap starts, so that the caffeine is in your system when you wake up. It takes caffeine 30 minutes to take full effect, so if you take a nap of about that length, the caffeine will be working when you wake up, and you may have fewer sleep inertia symptoms.

5 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute for Occupational Safety and Health (NIOSH). NIOSH Training for Nurses on Shift Work and Long Work Hours.

  2. Trotti LM. Waking up is the hardest thing I do all day: Sleep inertia and sleep drunkenness. Sleep Medicine Review. 2017;35:76-84. doi:10.1016/j.smrv.2016.08.005

  3. Hilditch CJ, McHill AW. Sleep inertia: current insights. Nature and Science of Sleep. 2019;11:155-165. doi:10.2147/NSS.S188911

  4. American Psychiatric Association. What are Sleep Disorders?

  5. Hilditch CJ, Dorrian J, Banks S. Time to wake up: reactive countermeasures to sleep inertia. Industrial Health. 2016;54(6):528-541. doi:10.2486/indhealth.2015-0236

By Wendy Wisner
Wendy Wisner is a health and parenting writer, lactation consultant (IBCLC), and mom to two awesome sons.