How to Stop Sleep Inertia – 6 Actionable Tips

Sleep inertia is the feeling of grogginess and disorientation that people sometimes experience upon awakening. It's often referred to as "morning drowsiness”, though it can occur after napping as well. But what exactly is sleep inertia, how can we reduce it, and what does it have to do with the sleep cycles and stages? Let's explore.

What is Sleep Inertia? 

The best way to understand sleep inertia is by thinking of it as a hangover. After a night out on the town, chances are you wake the next morning feeling groggy and disoriented. The after effects from alcohol impairs your performance significantly. Similarly, when you experience sleep inertia, your body feels groggy and disoriented because your brain is still experiencing the after effects of sleep.


Sleep inertia is not a sleep disorder but it can definitely be a nuisance, especially if you experience it often. Common effects include:

Poor physical reaction time: Sleep inertia can affect your overall cognition, but your physical reaction time is especially challenged right after waking up. This means you should not drive directly after waking up.

Worse decision making abilities: Studies shows that you are 51% less adept at making decisions in the first half hour after you wake up.

Bad memory: Almost half of the population will have a hard time remembering simple everyday information like passwords, names or directions. General disorientation is also part of the experience.

How to stop sleep inertia

To avoid sleep inertia, there are a few things you can do:

1. Make sure you are well rested

Science shows that sleep debt (that is, the accumulated lack of adequate sleep) worsens sleep inertia. Therefore, make sure to get enough sleep at night, typically 7-9 hours for adults.

2. Know your sleep chronotype

Your sleep chronotype refers to your natural sleep pattern, which is determined by your circadian rhythm. Science has shown that some people are hardwired to go to bed earlier in the evening or need a little more sleep in the morning. Find out whether you are a morning lark or a night owl, and try to adjust your schedule accordingly.

3. Have a coffee

Caffeine works by blocking a sleep-regulating molecule called Adenosine from binding with an A1 receptor – this is what gives you a jolt of energy and keeps drowsiness at bay. So drink up, but keep in mind that the effects of caffeine can last as long as 10 hours. 

4. Get some sunlight

Sunlight (and darkness) has a big effect on our circadian rhythm. When you are exposed to sunlight, cortisol and other hormones connected to wakefulness are released immediately, dispelling sleepiness. So it’s ideal to get some sun right after you wake up. 

5. Take a short nap 

Getting enough sleep at night is the best answer on how to stop sleep inertia, but it’s common for most people to be in sleep debt from time to time. A quick power nap in the afternoon is a great way to pay back sleep debt, and if you keep your nap below 20 minutes, it is unlikely to cause sleep inertia. You can also combine your nap with a cup of coffee beforehand for a nappuccino.

6. Exercise in the morning

Exercising in the morning isn’t for everyone but if you feel groggy upon awakening, getting the blood flowing is a great way to clear your mind. Exercise raises the body temperature (during sleep, our body temperature is at its lowest) and causes the release of cortisol, which promotes alertness. You can combine your morning workout with getting some sunlight for an extra refreshing effect. banner

Sleep Cycles and Sleep Inertia

The severity of sleep inertia is often connected to your sleep cycles. A sleep cycle has four stages: 3 non-REM (rapid eye movement) stages followed by a REM stage. For most people, a sleep cycle typically takes about 90 minutes. As we sleep, we connect the end of one sleep cycle to another until we wake up.

If undisturbed, you should naturally wake up at the end of a sleep cycle, when sleep is at its lightest. However, this is not always the case, as we sometimes need to wake up at a specific time. If you wake up during a deep sleep stage, your body will take a while to adjust and it can be difficult to feel fully awake for at least an hour. In fact your cognitive performance will be impaired by as much as 41%.

To avoid waking up during a stage of deep sleep, work backwards in increments of 90 minutes from when you need to wake up. For example, if you need to wake up at 6am, you should target a bedtime of 10:30pm in order to get 7.5 hours of sleep or five sleep cycles. 

Sleep drunkenness after napping

Sleep inertia does not only happen in the morning. It can also happen after daytime sleep. If you are a napper, the secret to avoiding grogginess upon awakening is to keep your nap duration short. 

With a power nap of 20-minutes or less, you are unlikely to experience grogginess when waking up. The good news is that 20 minutes is sufficient to dispel tiredness, promote alertness and improve cognition. Read more about the benefits of napping here.


Sleep inertia is a feeling of grogginess and disorientation that occurs upon waking up. The effects can be difficult to shake off, but can be avoided by getting enough quality sleep (aim for 7.5 – 9 hours) and waking up at the end of your sleep cycle. Additionally, exposing yourself to sunlight upon waking is the answer on how to stop sleep inertia. Above all, knowing what your body needs and following a regular routine will help you feel your best, every day of the week.