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Sleep Disorders

Unable to wake up



There seems to be a few hour span during the night when I am sleeping that I am unable to wake up - even when there is an emergency. I have slept through many "abnormal" situations such as fire alarms (both at home and while at university). I have also slept through other concerning emergencies. I cannot find any answers as to why I appear unable to wake, for any reason. Most people just respond by saying "I wish I could sleep like that", however, it worries me, especially since I have two children who I have been unable to respond to during the night when they have needed me or cried out in their sleep.


What you describe is probably at the extreme end of a normal phenomenon, and may not be abnormal, although several details are needed before this can be concluded. Normal sleep consists of 2 stages of sleep; NREM (which has 4 stages known as Stages 1 to 4) REM sleep (also known as dream sleep). Stages 3 and 4, also known as slow wave sleep (SWS), are the deepest sleep, and it is difficult to arouse from these two stages. Awakening from other stages of sleep is typically easier than awakening from Stages 3 and 4. SWS occurs most commonly in the first portion of the night and recurs in only small portions in the second half of the night. Therefore, it is common that a person is more difficult to arouse early in the night.

In addition, younger individuals tend to have an increased percentage of SWS and therefore, tend to manifest more difficulty awakening from sleep. Other factors such as menstrual period, physical activity, fever, and medications may contribute to changes in sleep architecture. Many individual who obtain less than the adequate sleep (about 7-8 hours) may suffer from a degree of sleep deprivation and sleep debt. These patients may experience a rebound in their SWS and would be more difficult to arouse on these nights they obtain their "makeup" sleep. An irregular sleep wake schedule and disruption of sleep can also cause changes in the normal sleep architecture leading to increased SWS on some nights or SWS late in the night

A detailed sleep history will help to determine if what you are experiencing is an extreme part of the normal sleep phenomenon or if there could be other explanations for your symptoms, such as a medication effect or an underlying sleep disorder (i.e. sleep apnea or narcolepsy). I recommend you talk to your doctor about your problem and they can then determine if referral to a Sleep Specialist is needed. In the meantime, proper sleep hygiene is critical. This means obtaining adequate sleep on a regular basis and not varying your sleep duration from night to night. Most individuals know how much sleep they need to feel rested and you should strive to achieve this consistently.

If you would like further information about sleep disorders or sleep itself, I recommend the American Academy of Sleep Medicine website. In addition to information about sleep medicine, the website also contains a list of accredited Sleep Centers and may help you to locate one nearest you.

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Response by:

Rami N Khayat, MD Rami N Khayat, MD
Clinical Associate Professor of Pulmonary, Allergy, Critical Care & Sleep
College of Medicine
The Ohio State University