What is Circadian rhythm sleep disorder?
'''Circadian rhythm sleep disorders''' happen when the [[circadian rhythm]] is not working correctly. The circadian rhythm is your body's regulatory system that operates during the 24 hour light/dark cycle. It regulates important bodily functions such as metabolism, body temperature, and hormonal release.<ref>{{Cite journal|last=Ahmad|first=Mahadir|last2=Md. Din|first2=Nur Syafiqa Balqis|last3=Tharumalay|first3=Ruthra Devi|last4=Che Din|first4=Normah|last5=Ibrahim|first5=Norhayati|last6=Amit|first6=Noh|last7=Farah|first7=Nor MF|last8=Osman|first8=Rose Azzlinda|last9=Abdul Hamid|first9=Mohamed Faisal|last10=Ibrahim|first10=Ibnor Azli|last11=Jamsari|first11=Ezad Azraai|date=2020-09-30|title=The Effects of Circadian Rhythm Disruption on Mental Health and Physiological Responses among Shift Workers and General Population|url=https://www.mdpi.com/1660-4601/17/19/7156|journal=International Journal of Environmental Research and Public Health|language=en|volume=17|issue=19|pages=7156|doi=10.3390/ijerph17197156|issn=1660-4601|pmc=PMC7579294|pmid=33007836}}</ref> The brain structure that is responsible for the circadian cycle is the suprachiasmatic nucleus.<ref>{{Cite journal|last=Abe|first=Michikazu|last2=Herzog|first2=Erik D.|last3=Yamazaki|first3=Shin|last4=Straume|first4=Marty|last5=Tei|first5=Hajime|last6=Sakaki|first6=Yoshiyuki|last7=Menaker|first7=Michael|last8=Block|first8=Gene D.|date=2002-01-01|title=Circadian Rhythms in Isolated Brain Regions|url=https://www.jneurosci.org/content/22/1/350|journal=Journal of Neuroscience|language=en|volume=22|issue=1|pages=350–356|doi=10.1523/JNEUROSCI.22-01-00350.2002|issn=0270-6474|pmc=PMC6757616|pmid=11756518}}</ref> When exposed to light, this structure secretes a hormone called cortisol, causing stimulation and arousal. However, when exposed to darkness, the suprachiasmatic nucleus secretes a hormone called melatonin, which is a sleep hormone. When the circadian rhythm is disrupted, there is an increased risk for a variety of health conditions such as cancer, cardiovascular