Every time your alarm clock goes off, you blearily open your eyes and feel the intense urge to hit snooze and go back to sleep — you just aren't ready to face the world yet. Privately, you wonder, "How do people wake up energetic and ready to take on the day?"
The truth is, few do. Marketing campaigns courtesy of mattress companies and sleep supplements have conditioned us to think we should wake up bright-eyed and bushy-tailed. When in reality, that is far from the case, even if you’ve met your sleep need (the genetically determined amount of sleep your body needs). The temporary stretch of grogginess that makes you feel like you can't wake up is called sleep inertia, and it’s naturally part of your sleep-wake cycle.
That being said, there are times when your sleep inertia is more intense than usual. Below, we'll detail the various causes of why you may find it more challenging to wake up and what you can do to lessen the grogginess. This way, you can start feeling as good as you can in the shortest time possible.
The next time you don't jump out of bed in the morning with your arms outstretched and excited to get going, don't beat yourself up. The same goes for waking up from an afternoon nap.
Instead, understand that your mind and body are going through sleep inertia, a completely normal biological process that happens every day, no matter how much sleep you've had the night before. A 2019 meta-analysis says it best: “Sleep inertia is the term used to refer to the temporary time of sleepiness, disorientation and impaired cognitive performance experienced upon awakening.” That’s why we call it your Grogginess Zone in the RISE app, which you can view on your Energy Schedule.
To understand why wake-up grogginess happens, we need to look at how sleep homeostasis works (one-half of the Two Laws of Sleep). You can picture sleep homeostasis as a seesaw that wants to be balanced. But, what causes it to go off balance? The answer: sleep pressure.
When you are awake, a drowsiness-inducing compound called adenosine gradually builds up in your brain, leading to ever-increasing sleep pressure. It's why you occasionally yawn throughout the day and, hopefully, fall asleep by your bedtime.
Mounting daytime sleep pressure unbalances the sleep homeostatic seesaw to tilt it on one side. When your brain purges adenosine during nighttime sleep or daytime naps, the seesaw resets.
One hypothesis to explain the grogginess you feel right after waking up in the morning or after a >25 minute nap is a lingering of adenosine that hasn’t fully cleared. However, the substrate for sleep inertia remains incompletely understood, and is likely to have multiple etiologies.
What we do know is that sleep inertia can last for 60-90 minutes or even upwards of three hours and is the prime contender for why it feels like you can’t wake up (meeting your sleep need may help to speed things up: learn how to calculate your sleep need here or use the RISE app, which will tell you yours).
Fun fact: Morning people aren't immune to wake-up sleep inertia, even though they may find it easier to shrug off the post-sleep haziness. Researchers found that early birds’ performance significantly improved within ~10–20 min after waking up. Meanwhile, the performance of night owls took half an hour or longer to reach the same level of improvements. The study tested performance pegged to participants’ regular bedtimes. (In another fun twist, it’s worth noting that the act of testing for sleep inertia can actually dissipate it. This means most studies that quantify the duration of sleep inertia underestimate its longevity.)
So, we've established that it's natural to feel like you can't wake up, at least for a while, after transitioning from sleep to wakefulness. That being said, various factors can intensify and prolong wake-up grogginess, preventing you from feeling and functioning at your best when you need to.
To understand how these factors amplify wake-up grogginess, we need to look at the circadian rhythm — the other half of the Two Laws of Sleep. This is your internal body clock that dictates the daily peaks and dips in your energy levels. The circadian rhythm also interacts with sleep homeostasis to influence your ideal sleep and wake times.
Keeping these two laws in mind, let's look at why you find it harder to wake up than usual.
Excessive yawning, brain fog, and a poor mood are the hallmarks of high sleep debt, the amount of sleep you've missed out on in the past 14 days relative to your sleep need. You can view your running sleep debt on the Sleep screen in RISE. (Head here to learn more about sleep debt and its repercussions in the short and long term.)
Later bedtimes, earlier wake times, and/or fragmented sleep invariably mean you’re skipping out on a few hours of sleep. Due to the lack of sleep, your brain doesn't have enough time to flush out the accumulated adenosine.
As a result, the sleep homeostatic seesaw remains unbalanced, and you're more prone to daytime sleepiness that quickly downgrades how you feel and function. Take note the same outcome applies to all-nighters or any other form of prolonged sleep deprivation.
Research shows a strong connection between sleep deprivation and sleep inertia. After slow-wave sleep is suppressed during sleep deprivation, it significantly rebounds during recovery sleep. This is accompanied by a sharp rise in sleep inertia the following morning.
Perhaps you’ve consistently had enough sleep yet still can't wake up in the morning. If that's the case, it’s worth asking yourself if you wake up at a consistent time across the week. If not, there’s a good chance your wake-up schedule is forcing circadian misalignment.
As much as a consistent sleep routine matters, so does a regular wake time. In fact, consistently waking up at the same time each day helps us fall asleep consistently at the same time each night. The reason being, early light starts the clock on timely sleep. A later wake-up time delays the various temperature, chemical, and hormone cycles light kickstarts, particularly that of melatonin, the sleep hormone. Later light than usual also dampens your body's cortisol rise, which will also make it harder to wake up. Instead of being in top form, what you get is a messed-up body clock and feeling worse than you normally do — hello, sleep hangover.
There are a few reasons why you might not be sticking to a regular rise time. Let's see if you're making any of the below mistakes that make waking up more challenging than usual.
All of us can relate to how tempting the snooze button looks at the crack of dawn. But succumbing to the urge will only throw off your body clock even more.
When you snooze for a few more minutes, your brain enters a new stage of the sleep cycle. A longer snooze time signifies higher odds of entering slow-wave sleep (aka deep sleep or non-REM sleep).
Research shows that waking up during the deeper stages of sleep intensifies your wake-up grogginess and can impair your performance by 41%. As you can imagine, it takes even longer for your brain to depart from dreamland and re-enter the world of full consciousness.
Many of us look forward to our days off when we have the luxury to sleep in. But a significantly late sleep-in will not bode well for your circadian rhythm, as changes in your sleep schedule confuse your biological clock.
This internal clock acts as a strict conductor directing the chemical, hormonal, and temperature changes needed to power up your system before you wake up. Sleeping in will only unsync your social and biological clock, inciting social jetlag that impacts some 87% of the general population according to expert chronobiologist Till Roenneberg. A later wake-up time also means you miss the energizing effects of the early morning cortisol surge, predictably worsening your "I can't wake up" vibes.
While we advocate for a nap during your afternoon dip to pay down sleep debt, bear in mind nap duration influences the severity of sleep inertia. The longer the nap, the more likely you can't wake up from your afternoon siesta.
That's because longer naps give you more time to enter slow-wave sleep, increasing the likelihood your alarm clock interrupts you during deep sleep. As a rule of thumb, longer naps (40-90 minutes) heighten post-nap grogginess compared to power naps of 10-20 minutes.
If you're burdened with high sleep debt, you may also feel like you can't wake up after a short nap of fewer than 30 minutes. Remember, your body has a backlog of adenosine to clear, hence the greatly intensified sleep inertia.
If you have little to no sleep debt and adhere to a consistent sleep schedule yet still can't wake up on most days, health problems may be at play.
For instance, sleep drunkenness (a more severe form of sleep inertia) is featured in sleep disorders like idiopathic hypersomnia and narcolepsy (which may include nighttime sleep paralysis). Other sleep disorders — like insomnia, restless legs syndrome, and obstructive sleep apnea — disrupt your sleep patterns, making it harder for you to meet your sleep need.
Similarly, parasomniac sleep problems like sleep-talking, sleepwalking, and night terrors don’t just cause poor sleep for you but also your bed partner or roommate. Without a good night of sleep, it's no wonder you (and the affected parties) can't wake up the next day.
Mental health conditions, like depression and bipolar disorder, also worsen wake-up grogginess. The same goes for circadian rhythm disorders like shift work sleep disorder. You should also know that some medications, such as beta-blockers (for blood pressure) and antidepressants, can make it harder to get out of bed in the morning.
Even though the sensation that you can't wake up after sleep is part and parcel of your sleep-wake cycle, it can have serious consequences on your personal safety and others’ under certain circumstances.
According to a 2019 review, the way sleep inertia downgrades your day-to-day functioning is akin to (or even greater) than 40 hours of sleep deprivation. These impairments span everything from "simple reaction time tests to complex cognitive tasks."
Letting the numbers speak for themselves, an analysis of U.S. Air Force flight accidents showed that pilot-error-based incidents peaked upon "waking from the night sleep." As you can see, there is a real safety concern related to feeling groggy. This could affect your job and the people you serve (such as if you’re a pilot, a firefighter, or a doctor), but it could also come into play during your morning commute to the office.
How, then, can you stop feeling like you can't wake up? For most of us, that begins with good sleep hygiene that's tied to your circadian rhythm. Practicing healthy sleep habits from dawn till dusk goes a long way to keep your sleep debt low and your circadian rhythm on track to minimize wake-up grogginess as much as possible.
We've talked about how high sleep debt hikes up morning grogginess, which is why it's a no-brainer that keeping sleep debt low is crucial to how you feel when you wake up. That being said, it can be hard to know how much sleep you need, much less the amount of sleep you've missed out on.
This is where RISE can help. The app uses sleep-science-based models and the past 365 nights of sleep data tracked by your phone to learn your unique sleep biology and calculate your sleep need in hours and minutes.
From there, it's easy to use your sleep and wake times to determine how much running sleep debt you have, which you can view on the Sleep screen in the app. As a rule of thumb, keep your sleep debt to five hours and below, so you can feel and function at your best (or as close to it as possible).
RISE users on iOS 1.202 and above can click:
Because your circadian rhythm also determines how you feel when you wake up, it only makes sense to stay in circadian alignment as much as possible. The easiest way to do that is to keep a consistent sleep schedule that's aligned to your chronotype (your biological preferences for sleeping and waking).
With that said, night owls might find it hard to maintain an early-bird schedule due to work and social obligations. If that's the case, you can take steps to shift to an earlier sleep schedule. Our guide on "How to become a morning person" guides you through the process. Bear in mind, though, this will be an active, ongoing effort you need to keep on top of. Otherwise, your biological clock will simply revert back to square one — with later sleep and wake times.
And if you really want to sleep in, ensure it's no later than an hour past your usual wake time to downplay the risk of circadian misalignment. Head here for more science-backed tips on how to make the most of sleeping in.
There are a few things you can do to shorten your time spent in the Grogginess Zone. Here's how:
When used at the right times according to your circadian rhythm, these simple but effective tactics help you feel less like you can't wake up.
If you've tried all of the above measures and still find no relief, particularly if you have a medical condition, it's time to consult your primary doctor or a sleep specialist.
A licensed healthcare professional can help you pinpoint the underlying causes of your sleep problems and give you medical advice on the right treatments. This could be anything from sleep medicine to cognitive behavioral therapy for insomnia (CBTI). Also, if you suspect your medications are making it hard for you to wake up, consult your doctor for alternatives.
The reason why you can't wake up fully after snoozing is very likely due to sleep inertia. High sleep debt and circadian misalignment further intensify the wake-up drowsiness. To minimize the interfering effects of sleep inertia on your day-to-day functioning, perfect your sleep hygiene to keep sleep debt low and your circadian rhythm aligned.
Because sleep inertia can adversely affect your personal safety and the safety of others, as mentioned earlier, RISE can help you plan your day with your Grogginess Zone in mind, especially if you foresee a crucial task that requires your cognitive functioning to be up to speed.
Rather than jump on an important sales call right after your alarm sounds, take care of the routine stuff first. Put away the breakfast dishes or plan the day’s to-do list — it will keep you feeling productive even when you aren’t firing on all cylinders just yet. Even better if you finish writing your list just as your morning peak starts so you can hit the ground running with your most important tasks.
In the case of napping, always give yourself enough buffer time for the sleepiness to fully wean off. For example, if you pull over to the side of the road to nap so you can avoid falling asleep while driving, do not start driving right after you wake up.
In essence, sleep inertia is an inescapable part of your sleep-wake cycle. So, while you may not be able to completely eradicate wake-up grogginess, an app like RISE combined with the earlier recommendations can tone down the worst of it to help you start your day on a good (and safe) note.
RISE users on iOS 1.202 and above can click:
Sleep inertia, or wake-up grogginess, is the main reason you’re unable to fully wake up in the morning or after a nap. It’s a completely normal part of your sleep-wake cycle that’s intensified by factors like high sleep debt and circadian misalignment (caused by sleeping in, social jetlag, and travel jet lag).
You’re likely experiencing sleep inertia, a completely normal phase of your sleep-wake cycle. While sleep inertia occurs even when you’ve met your sleep need, it’s harder to shake off the grogginess when you’re sleep-deprived or battling with social and travel jet lag.
When you try to wake up but can’t, you’re likely experiencing sleep paralysis. This is when you’re conscious but unable to move any part of your body as your muscles are temporarily paralyzed. While sleep paralysis isn’t dangerous, it can create a lot of anxiety and distress that impact sleep, even after the episode. Keeping your sleep debt and anxiety levels low, along with practicing circadian alignment, can help reduce the frequency of sleep paralysis.
Common symptoms when you have difficulty waking up include: sleepiness, disorientation, and impaired cognition. Contrary to popular misbelief, it’s natural to have these symptoms when you’re waking up in the morning or after a nap as your body goes through sleep inertia. That said, high sleep debt and circadian misalignment worsen these symptoms.
To wake up early and not feel tired, it helps to have low sleep debt and strongly aligned circadian rhythms honed through healthy sleep hygiene. This includes a consistent sleep schedule, well-timed light exposure, and a bedroom environment primed for sleep. You should also take your chronotype into account to see if you need to shift your sleep schedule to better match your social clock.
If you can’t wake up no matter how much sleep you get, it helps to know your true biological sleep need to make sure you’re not under-sleeping and accumulating sleep debt. When you’re sleep-deprived, it can take days and even weeks for your body to reduce its sleep debt. During this period of adjustment, you’re likely to feel extremely groggy upon waking up, coupled with excessive daytime sleepiness and lower energy levels. Another reason would be circadian misalignment, in which you’re meeting your sleep need but your sleep and rise times are at odds with your body’s natural sleep-wake cycle. Lastly, a medical condition might also be at play.
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