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, no one does. 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. 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. 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 fall asleep by your bedtime.
Mounting daytime sleep pressure unbalances the sleep homeostatic seesaw and tilts it on one side. When your brain purges adenosine during nighttime sleep or daytime naps, the seesaw returns to baseline.
In the morning or after a nap, lingering dregs of adenosine cause you to feel groggy when you wake up. It typically takes 60-90 minutes for the adenosine residue to disappear, provided that you've consistently met your sleep need (the genetically determined amount of sleep you need).
The gradual dissipation of adenosine come morning or post-nap makes you feel like you can't wake up. In 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.
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 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.
Think about it, a later bedtime, an earlier wake time, and/or fragmented sleep invariably means you are skipping out on a few hours of sleep. Consequently, your brain doesn't have enough time to flush out the accumulated adenosine.
In which case, the sleep homeostatic seesaw remains unbalanced, and you're more prone to daytime sleepiness that downgrades every aspect of your life that matters. Take note that the same spiel applies to all-nighters or any other form of prolonged sleep deprivation.
If you want hard proof, a 2000 sleep study examined the relationship between sleep deprivation and sleep inertia. After slow-wave sleep was suppressed during sleep deprivation, it significantly rebounded during recovery sleep. This was accompanied by a sharp rise in sleep inertia the following morning.
Perhaps you consistently had enough sleep yet still can't wake up in the morning. If that's the case, pause and ask yourself, “Am I consistent with my rise times?” If not, your wake-up schedule is at odds with your circadian rhythm, leading to circadian misalignment.
As much as a consistent bedtime matters, so does an undeviating rise time. The reason being, your body's cortisol levels peak in the early morning, a biological process known as the cortisol awakening response (CAR).
The spike in this alertness hormone helps transition you from sleep to wakefulness. It also gives you a much-needed invigorating boost that serves as the foundation of your morning energy peak.
Sleeping past your usual rise time means you inevitably miss out on this early morning cortisol surge and possibly your first energy peak of the day. A later wake-up time also delays light signals to the suprachiasmatic nucleus (the master clock in your brain), further dampening your body's cortisol rise. 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 give you more trouble when waking up.
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 sleep phase. A longer snooze time signifies higher odds of entering slow-wave sleep (or deep sleep).
Research shows that waking up during deep sleep intensifies your wake-up grogginess and impairs 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.
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 that 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, in which case your alarm clock is more likely to interrupt you during deep sleep. As a rule of thumb, deep 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).
Because your circadian rhythm also determines the length and depth of how you feel when you wake up, it only makes sense to stay circadian-ally aligned 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 always take steps to shift to an earlier sleep schedule. Our guide on "How to become a morning person" gives you all the info you need. Bear in mind, though, that this will be an active, ongoing process that 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 that it's no later than an hour of your usual wake time to downplay the risk of circadian misalignment.
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 due to sleep inertia. Other triggers like 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 more 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.
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