Sleep and Circadian Rhythms the Suprachiasmatic NucleiWith sleep and circadian rhythms, it is observed in everything from plantand animals to fungi and bacteria - and of course humans. The termcircadian is from the Latin circa, meaning "around" and dies / diem whichmeans "day" - giving us a literal definition of "about a day".It is a kind of built in clock that tells us when to be awake and when weshould be sleeping. This "clock", whose scientific name is suprachiasmaticnuclei (SCN), rests in a region of the brain around where the optic nervescross. The SCN is adjusted primarily by daylight but also by other externaltime cues called zeitgebers - which can be anything from the beeping ofyour alarm to the timing of specific meals. Light reaching this area throughthe retina, are turned into signals which continue their way up the opticnerve, finding its way to the SCN.The suprachiasmatic nucleihas many functions, sendingout signals to many differentareas of the brain whichcontrol things like theproduction of melatonin andthe secretion of otherhormones, the production ofurine, the governing of bodytemperature as well aschanges in our bloodpressure.
Scientific studies (in particular one done by Czeisler et al. at Harvard) haveproven that the free-running range of a healthy adults circadian rhythm isabout 24 hours and 11 minutes (plus or minus 16 minutes). Basically, ourbodys clock follows the same cycle as the 24 hour rotation of the Earth.Weve already learned that light resets our biological clock or oursuprachiasmatic nuclei. Light also has the ability to delay or advance ourcircadian rhythm depending on the timing, the type of light and theamount of light. It is not known exactly at what levels light starts to affectour sleep and circadian rhythms but some researchers believe the numberto be upwards of 1000 lux. Sleep and circadian rhythms - DisruptionsWeve learned that both light and timing play animportant role between the association of sleep Related Articlesand circadian rhythms. Disruptions in yourcircadian rhythm can cause sleeping disorders Why We Sleepas well as other issues such as general fatigue, 5 Sleep Stagesloss of appetite, lack of alertness etc. These What is Insomnia?symptoms, which are normally associated with a What is Sleep Apnea?lack of sleep, are referred to as circadian rhythm What is Narcolepsy?sleep disorders.
Not being able to get to sleep at night can bea horrible experience - at night as well asthroughout the following day. But it doesnthave to be that way - sometimes all it takes isa few lifestyle adjustments. Learn what youneed to know to instantly fall asleep eachnight in the sleep ebook, Get to Sleep Now! 39 Ways to Guarantee Your ZZZs.