Morning Grogginess: Waking Up Tired With Sleep Inertia

7 Min Read | By Matthew Fox

Last Modified 13 March 2024   First Added 31 August 2023

This article was written and reviewed in line with our editorial policy.

Getting out of bed can sometimes feel like a battle. Our vision can be blurry, our brains confused, and we have no idea what day it is. Fighting the urge to slip back under the covers and close your eyes is easier said than done.

Even after a full 8 hours of sleep, it can be difficult to slip out of your snooze and prepare for the day ahead. This is what’s known as sleep inertia — a common condition where you can’t shake the haze of slumber. In this article, we’ll discuss the whats and whys and suggest ways to help prevent the wake-up struggle.

What exactly is sleep inertia?

According to, Sleep inertia (also termed sleep drunkenness) refers to a period of impaired performance and reduced vigilance following awakening from the regular sleep episode or from a nap. This impairment may be severe, last minutes to hours, and be accompanied by polygraphically recorded microsleep episodes.

In layman’s terms, this simply means that feeling of grogginess when we wake. And it’s typically what causes us to fall into microsleeps as we begin our day.

Why am I waking up tired?

You may think you shouldn’t wake up tired after 8 hours of sleep. This monophasic sleeping pattern should be enough to see you leaping out of bed in the morning, right? Well, not quite. Just like those old Windows PCs of the early 2000s, it takes your body a fair bit of time to ‘boot up’.

Our sleep cycle consists of four stages and it’s the transition from the final stage into a waking state which causes sleep inertia.

During sleep, particularly the deeper phases, our bodies are immobilized with relaxed muscles and a low heart rate. If we are awoken in these stages of deep sleep, our bodies haven’t had time to set in motion what they need to wake up cleanly.

It’s best to wake in the REM stage of sleep. In this phase, your brain is at its most active. When we wake during REM, our body isn’t as deeply in slumber and we can more quickly adapt to the day ahead. As mentioned, it works the opposite way too, so it’s important to try and set your alarm to wake up when you’re sleep is at its lightest.

Top tip:

Use our sleep cycle calculator to identify when you are likely to be in your REM sleep phase. All we need is your usual or planned bedtime and our tool will do the rest.

To truly understand sleep inertia, we also need to be aware of how our bodies wake up.

The trigger to move out of our sleep state is stimulated by the Reticular Activating System (RAS). The RAS responds to external stimuli, such as the sound of the alarm clock or the rays of sunlight breaking through the curtains. The RAS then sends electrical signals to the parts of the brain that need activation to wake up. The issue is that once we do awaken, we still have a build-up of chemicals that we use to help us sleep.

Although scientists are still not exactly certain on what bodily processes cause us to wake, there is an understanding of how we fall asleep.

The melatonin hormone and adenosine neurotransmitter are both key players for getting us to sleep and keeping us there. In relation to sleep inertia, studies suggest these linger on when we wake up.

It’s only once these chemicals have fully dispersed that we start to feel fully awake. It’s their presence post-sleep that causes the ‘sleep drunkenness’ we feel in the early mornings.


What are the symptoms of sleep inertia?

Sleep inertia can last as little as 20 minutes or stray beyond an hour, depending on how many hours of sleep you managed to get, the quality of your sleep, and the sleep phase in which you woke.

Sleep inertia symptoms can be any or all of the following:

  1. Impaired cognitive functioning: Once awake, you may feel incapable of anything. Concentration can be a struggle, and even the simplest tasks like brushing your teeth or pouring a cup of tea may be difficult.
  2. Confusion: Feeling disorientated straight after waking up is common for people with sleep inertia. It can take a few moments to figure out who and where you are. In extreme cases, this can last beyond the first few moments of a new day.
  3. Negative moods: A bad mood in the morning can be a sign you are suffering from sleep inertia. Irritability, mood swings, and even depression may be the rational parts of your brain taking a nap.
  4. Motor impairments: Poor physical coordination can often occur moments after waking. Your limbs are not quite firing on all cylinders and even walking feels like you are stepping on a tightrope.
A man wakes up from a brown and light blue bed, and holds his head in his hand as though he is still tired.

Is there a cure for sleep inertia?

Sadly, there’s no medical cure for sleep inertia. However, it is something that’s being studied constantly, so don’t give up hope. Plus, there are many ways you can prevent the symptoms and reduce the time it takes to feel alive again in the early mornings.

  1. Stick to a sleep schedule – Making a routine to go to bed at the same time each night allows your body to set its internal clock, otherwise known as your circadian rhythm. Unfortunately, it’s best if you apply this to weekends too. You’ll thank yourself on Monday morning.
  2. Prevent midnight disruptions – Ensuring that nothing will wake you during your night’s rest is vital for a healthy sleep. Our RAS is triggered by external stimuli, such as noise, light, and temperature changes. Of course, the body’s calls to wake, such as needing the toilet in the middle of the night, can also be a trigger.
  3. Caffeine for breakfast – Sometimes sleep inertia is inevitable, but a boost of energy can give your brain the wake-up call it needs. Caffeine blocks the adenosine receptors in our brains and stops the neurotransmitter from dispersing through our brain. But go easy; just one cup can be enough to supercharge the body. It’s also worth noting here that because caffeine blocks adenosine, once the effects have ran out, the adenosine will kick back in. Perhaps consider other morning drinks which energise such as ginger shots or pure orange juice.
  4. Plan a morning routine – Now, we are not suggesting you have to mimic a morning routine like the rich and famous, but giving yourself time in the morning to naturally awaken can be enough to combat the effects of sleep inertia. Try simple morning activities, such as a stroll in the garden or light yoga. We have many healthy morning routine tips to wake the body and mind after sleep.
  5. Brave the cold shower – We know a cold shower in the morning doesn’t exactly sound like an ideal way to start the day, but that ice cold burst can work wonders for our energy levels and can even help reduce anxiety and stress.

Is it normal to have sleep inertia?

Feeling tired and groggy when waking up every day is entirely natural. Your body will always need time to charge up. However, if you feel like your mornings are difficult or are impacting the start of your day, speak to your GP about potential sleeping disorders. Identifying what may be causing your problems or changing your bedtime routine could do the trick.

In the meantime, discover the many ways you can get a better night’s sleep to prevent sleep inertia from dragging you down in the morning.

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