Sleep Inertia

Everybody loves a good nap! Whether it is in the middle of a long day or that casual Sunday morning nap, it isn’t just a very refreshing activity; it’s also pretty fun! It has tons of benefits like restoring alertness, enhancing performance as well as reducing the chance of mishaps.

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    It may, however, not been the best option for some people like the ones who need their beds to sleep at any time, or the ones who can’t sleep during the day. Similarly, taking too many naps or sleeping for prolonged periods of time during the day can also be detrimental to your health. There are some questions that you need to ask yourself. Why do I feel sick after a nap? Or why do I feel nauseous after a nap?

    Naps – especially the ones that last more than 10-20 minutes – can have a really bad effect on some people, leaving them with sleep inertia, a condition that can cause problems for those individuals who must perform some important tasks immediately after waking from the nap.

    Have you heard of the term sleep inertia before? There are many people who aren’t familiar with this condition, because of which many people who are suffering from the problem can’t even tell that they have this!

    Keep reading to find out all you need to know about the physiological state!

    What Is Sleep Inertia?

    Sleep inertia is defined as a physiological state of impaired cognitive and sensory-motor performance – commonly described as the feeling of grogginess and disorientation – that you experience immediately after waking up, which can alter your day-to-day functioning.

    This means that you can wake up after naps – mostly the slightly longer ones that last for over 30 minutes – and feel some intense drowsiness and disorientation combined with a decline in motor dexterity. This usually happens when you wake up from a periods of deep sleep.

    This state usually lasts anywhere between a few minutes to half an hour. In some cases, however, sleep inertia can last up to even 4 hours. These cases are not as common but even the shorter periods of sleep inertia can be detrimental to those people who need to perform as soon as they wake up from the nap.

    The disorientation and post-sleep impairment can be more severe and last for longer periods in those people who are already sleep deprived or those who have taken naps for periods that are longer than those recommended for restoring alertness. This is also commonly felt by people who use a regular alarm clock to wake up in the morning.


    Also referred to as sleep drunkenness, sleep inertia is a condition that you may be experiencing for a while without even realizing that there is a term for it. Do you wake up feeling tired? Do you feel excessively groggy in the morning? Is it difficult for you to concentrate on basic tasks for some time after you wake up? Are your naps making you even more tired that you were before?

    If the answer to the above questions is yes, it is very likely that you are suffering from sleep inertia.

    Sleep inertia isn’t just that feeling of sleepiness, it also impairs the cognitive and psychomotor abilities of the human body immediately after a person wakes up. To simplify it, this means that your ability to make decisions or perform any type of complex activities will be impaired, maybe even causing unnecessary complications.

    You may not have to perform tasks that are extremely dangerous – like working in a mine – but sleep inertia can also make it tough for you to drive a car safely in the morning when you wake up. Other than the grogginess, you may experience a strong desire to go back to sleep or small, tough to resist sleep attacks.


    Sleep inertia is caused because of sudden awakening during rapid eye movement (REM) sleep. Found in mammals and birds, REM sleep is a phase that is distinguished by the rapid movement of the eyes and low muscle tone throughout the body combined with more vivid dreams. This type of sleep is essential for stimulating the regions of the brain that are used in learning and is associated with increased production of proteins.

    If you wake up during REM sleep, your body still has high levels of melatonin that causes sleepiness. Higher levels of melatonin are observed during REM if you sleep for longer. On the other hand, if you wake up during non-REM sleep, you feel more energized and alert as your blood pressure, heart rate and brain activity are relatively slower.

    Symptoms of sleep inertia are most likely to show up after you wake up abruptly from deep or slow-wave sleep or if the time for which you slept was not sufficient. If the body is deprived of sleep, waking up can also be difficult or if you are trying to wake up earlier than the usual time, you may face similar difficulties.

    There is still little clarity on why symptoms last as long as they do for most people but one theory also suggests that the cause behind sleep inertia is the build-up of a neurotransmitter called adenosine within the brain while you sleep.

    Sleep disorder like sleep apnea – where a person snores or witnesses pauses in breathing – or delayed sleep-wake phase disorder – a condition associated with a delayed natural ability to fall asleep at the start of the night – can make sleep inertia even worse. It is recommended that you see a doctor to deal with these issues when you are trying to fix sleep inertia.


    There is no particular course of treatment for sleep inertia or a sleep inertia cure as such. There are, however, steps that you can take to ensure that you’re getting good sleep. It is essential that you not only concentrate on the quantity of sleep but also the quality. This means that you sleep for sufficient number of hours so that your body’s needs are met and you also get the right type of sleep. It should not be full of disturbances.

    Under regular circumstances, most adults require at least seven to nine hours of sleep every night to wake up feeling well rested. Children may need more hours of sleep while older adults may be able to get on with their regular life on not as much sleep – maybe around eight hours every night.

    The next important step for treating sleep inertia is to effectively treat any other sleep disorders that you may be suffering from at the same time. An example of this is sleep apnea, which may also enhance sleep inertia. Treating such conditions will help in improving the quality of sleep that you are able to get. Improving the quality of sleep will lead to lesser grogginess and sleep inertia when you wake up in the morning.

    Another great way to wake up more energized and reduce the amount of disorientation that you may be feeling when you wake up in the morning is exposure to morning sunlight. Letting sunlight flow into your room helps to initiate the circadian alerting signal, which means that your body will automatically feel more refreshed.

    Finally, if these methods do not work, you may have to turn to caffeine or prescription stimulant medications, with the help of a doctor, to tackle your sleep inertia in the morning.

    There are a number of causes for sleep inertia and it can manifest in a large number of ways. Try making changes to your lifestyle to deal with sleep inertia but if such steps fail and the condition persists, you will need to consult a doctor. An expert in the field will be able to diagnose the condition in a better way after carrying out a further evaluation. The doctor may be able to help you after conducting a sleep test.

    Sleep is an integral part of leading a good life and it should have a refreshing effect on you. Dealing with your sleep inertia is an essential part of getting good sleep, so don’t delay it further and seek treatment!