- Sleep inertia
Sleep inertia is a physiological state characterised by a decline in motor
dexterity and a subjective feeling of grogginess, immediately following an abrupt awakening. Sleep inertia can also refer to the tendency of a person to want to return tosleep ing, even after suitable rest has been achieved. Typically, sleep inertia lasts up to 3 hours for a night wake up and up to 90 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.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 . Awakening from deep sleep - stages 3 and 4 ofnon-rapid eye movement sleep - has more sleep inertia than awaking from other sleep phases.
* Time of sleep. Sleep inertia is thought to be related to the phase of the body'scircadian rhythm . Waking during a trough inbody temperature tends to produce more sleep inertia.
* Chemical influences. Studies have shown that drugs such ascaffeine suppress the effect of sleep inertia, possibly by blockingadenosine receptors in thebrain .According to Patrick Sherry, who specializes in rail safety, sleep inertia can be more severe and last longer when a nap follows a prolonged period of wakefulness or an accumulated
sleep debt . Sleep inertia can often be reversed by activity and noise as well as caffeine. Reaction time performance is directly related to sleep stage at awakening; persons awakened during stage 4 sleep (the deepest) yield maximum reaction times. [cite web
url= http://mysite.du.edu/~psherry/fatigue/sleep.html |title= The Science of Sleep and Fatigue |accessdate= 2008-06-01 |last= Sherry |first= Patrick |year= 1999 |month= March |format= |work= monograph |publisher= University of Denver |pages= |quote= ]Cause
One theory is that sleep inertia is caused by the build-up of
adenosine in the brain duringnon-REM sleep .Adenosine then binds to receptors, which produce the feelings of tiredness.References
ee also
*
Circadian rhythm sleep disorder
*Delayed sleep phase syndrome External links
* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11683484&dopt=Abstract Abstract: Caffeine eliminates psychomotor vigilance deficits from sleep inertia]
* [http://www.findarticles.com/p/articles/mi_m0IBT/is_10_58/ai_92949462 Flying Safely Article on Napping]
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