Sleep inertia
From Wikipedia, the free encyclopedia
Sleep inertia is a physiological state characterised by a decline in motor dexterity and a subjective feeling of grogginess, immediately following an abrupt awakening from deep sleep. Typically, sleep inertia lasts between 15 and 20 minutes for a night wake up and 5-10 minutes for a day wake up. If the subject is awakened due to a perceived danger, however, the duration of sleep inertia is reduced to only a few seconds.
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[edit] Factors
NASA studies have shown that a variety of factors influence the severity and duration of sleep inertia. These include:
- Depth of sleep when woken. After roughly 30 minutes, the body enters into deep sleep. Waking from deep sleep induces more sleep inertia than otherwise.
- Time of sleep. Sleep inertia is thought to be related to the phase of the body's circadian rhythm. Waking during a trough in body temperature tends to produce more sleep inertia.
- Chemical influences. Studies have shown that drugs such as caffeine suppress the effect of sleep inertia, possibly by blocking adenosine receptors in the brain.
[edit] Cause
The cause of sleep inertia is not clear. One theory is that it is caused by the build-up of adenosine in the brain during non-REM sleep. Adenosine then binds to receptors, which produce the feelings of tiredness.
