Editing Jet lag (section)

===Double desynchronisation===
Double desynchronisation is the misalignment between: The body's internal clocks and the external environment (e.g., local time at your travel destination) and the body's central and peripheral circadian clocks (i.e., misalignment within different parts of your own body). 

There are two separate processes related to biological timing: [[circadian oscillator]]s and [[homeostasis]].<ref>{{cite journal |doi=10.1016/s1087-0792(98)90052-1 |title=Models of human sleep regulation |date=1998 |last1=Beersma |first1=Domien G.M. |journal=Sleep Medicine Reviews |volume=2 |issue=1 |pages=31–43 |pmid=15310511 |url=https://pure.rug.nl/ws/files/14639214/1998SleepMedRevBeersmaCorr.pdf }}</ref><ref name="dijk">{{cite journal |last1 = Dijk |first1 = D. J. |last2 = Lockley |first2 = S. W. |year = 2002 |title = Invited Review: Integration of human sleep–wake regulation and circadian rhythmicity |journal = Journal of Applied Physiology |volume = 92 |issue = 2 |pages = 852–862 |doi = 10.1152/japplphysiol.00924.2001 |pmid = 11796701 }}</ref> The master clock of the circadian system is located in the [[suprachiasmatic nucleus]] (SCN) in the [[hypothalamus]] of the brain. There are also peripheral oscillators in other tissues and organs, each having their own oscillatory rates that could be synchronized to the SCN oscillatory rate. The SCN's role is to send signals to the peripheral oscillators, which synchronise them for physiological functions. The SCN responds to light information sent from the [[retina]] and entrains its circadian rhythm to the external environment. It is hypothesised that peripheral oscillators respond to internal signals such as hormones, food intake, and "nervous stimuli" and may take longer time to synchronize to local time.<ref name="brown">{{cite book |last1 = Brown |first1 = S. A. |last2 = Azzi |first2 = A. |name-list-style = amp |year = 2013 |chapter =  Peripheral circadian oscillators in mammals |title = Circadian clocks  |pages =  45–66 |publisher = Springer |location =  Berlin}} {{cite book |author =  Center for Substance Abuse Treatment |title = Managing Depressive Symptoms in Substance Abuse Clients During Early Recovery |location = Rockville, MD |publisher = Substance Abuse and Mental Health Services Administration |year = 2008 |series = Treatment Improvement Protocol (TIP) Series, No. 48. |chapter = Appendix D: DSM-IV-TR Mood Disorders |chapter-url = https://www.ncbi.nlm.nih.gov/books/NBK64063/}}</ref>

The implication of independent internal clocks may explain some of the symptoms of jet lag. People who travel across several time zones can, within a few days, adapt their master clock SCN with light from the environment earlier. However, their [[skeletal muscle]]s, [[liver]], [[lung]]s, and other organs may adapt at different rates (peripheral circadian clocks may lag behind).<ref>{{cite journal |last1=Yamazaki |first1=Shin |last2=Numano |first2=Rika |last3=Abe |first3=Michikazu |last4=Hida |first4=Akiko |last5=Takahashi |first5=Ri-ichi |last6=Ueda |first6=Masatsugu |last7=Block |first7=Gene D. |last8=Sakaki |first8=Yoshiyuki |last9=Menaker |first9=Michael |last10=Tei |first10=Hajime |title=Resetting Central and Peripheral Circadian Oscillators in Transgenic Rats |journal=Science |date=28 April 2000 |volume=288 |issue=5466 |pages=682–685 |doi=10.1126/science.288.5466.682 |pmid=10784453 |bibcode=2000Sci...288..682Y }}</ref> This internal biological de-synchronisation is exacerbated as the body is not in sync with the environment{{snd}}a ''double desynchronisation'', which has implications for health and mood.<ref>{{cite journal |last1=Wirz-Justice |first1=Anna |title=Biological rhythm disturbances in mood disorders |journal=International Clinical Psychopharmacology |date=February 2006 |volume=21 |issue=Supplement 1 |pages=S11–S15 |doi=10.1097/01.yic.0000195660.37267.cf |pmid=16436934 }}</ref>