Editing Jet lag (section)

==Signs and symptoms==
The symptoms of jet lag can be quite varied, depending on the amount of time zone alteration, time of day, and individual differences. [[Sleep disturbance]] occurs, with poor sleep upon arrival or sleep disruptions such as trouble falling asleep (when flying east), early awakening (when flying west), and trouble remaining asleep. [[Cognitive]] effects include poorer performance on mental tasks and [[attentional control|concentration]]; dizziness, [[nausea]], [[insomnia]], confusion, [[anxiety]], increased [[fatigue]], [[headache]]s, and [[irritability]]; and problems with digestion, including [[indigestion]], changes in the frequency and consistency of [[bowel movements]], and reduced [[appetite]].<ref>{{cite web |last1=Doyle |first1=Ashley |title=What is a Jet Lag? |url=https://savvysleeper.org/what-is-jet-lag/ |date=10 January 2020 |website=Savvysleeper |access-date=3 June 2020 |archive-url=https://web.archive.org/web/20200925234923/https://savvysleeper.org/what-is-jet-lag/ |archive-date=25 September 2020}}</ref> The symptoms are caused by a circadian rhythm that is out of sync with the [[day–night cycle]] of the destination,<ref name="pmid17398311">{{cite journal |last1=Waterhouse |first1=Jim |last2=Reilly |first2=Thomas |last3=Atkinson |first3=Greg |last4=Edwards |first4=Ben |title=Jet lag: trends and coping strategies |journal=The Lancet |date=March 2007 |volume=369 |issue=9567 |pages=1117–1129 |doi=10.1016/S0140-6736(07)60529-7 |pmid=17398311 }}</ref> as well as the possibility of internal desynchronisation. Jet lag has been measured with simple analogue scales, but a study has shown that these are relatively blunt for assessing all the problems associated with jet lag. The Liverpool Jet Lag Questionnaire was developed to measure all the symptoms of jet lag at several times of day, and has been used to assess jet lag in athletes.<ref>{{Cite journal |last1 = Waterhouse |first1 = J. |last2 = Edwards |first2 = B. |last3 = Nevill |first3 = A. |last4 = Carvalho |first4 = S. |last5 = Atkinson |first5 = G. |last6 = Buckley |first6 = P. |last7 = Reilly |first7 = T. |last8 = Godfrey |first8 = R. |last9 = Ramsay |first9 = R. |title = Identifying some determinants of 'jet lag' and its symptoms: A study of athletes and other travellers |journal = British Journal of Sports Medicine |volume = 36 |issue = 1 |pages = 54–60 |year = 2002 |pmid = 11867494 |pmc = 1724441 |doi = 10.1136/bjsm.36.1.54 }}</ref>

Jet lag may require three hour or more hours of time zone change to occur, but some individuals can be affected by a single hour of time zone change which can include the single-hour shift to or from [[daylight saving time]].<ref name = "pmid17398311"/> Symptoms and consequences of jet lag can be a significant concern for [[Athletics (sport)|athletes]] travelling east or west to competitions, as performance is often dependent on a combination of physical and mental characteristics that are affected by jet lag. This is often a common concern at international sporting events like the [[Olympics]] and [[FIFA World Cup]]. However many athletes arrive at least 2–4 weeks ahead of these events, to help adjust from any jet lag issues.<ref name="pmid22299812">{{Cite journal |last1=Forbes-Robertson |first1=S. |last2=Dudley |first2=E. |last3=Vadgama |first3=P. |last4=Cook |first4=C. |last5=Drawer |first5=S. |last6=Kilduff |first6=L. |year=2012 |title=Circadian Disruption and Remedial Interventions |journal=Sports Medicine |volume=42 |issue=3 |pages=185–208 |doi=10.2165/11596850-000000000-00000 |pmid=22299812 }}</ref>

===Travel fatigue===
Travel fatigue is general fatigue, disorientation, and headache caused by a disruption in routine, time spent in a cramped space with little chance to move around, a low-oxygen environment, and [[dehydration]] caused by dry air and limited food and drink. It does not necessarily involve the shift in circadian rhythms that cause jet lag. Travel fatigue can occur without crossing time zones, and it often disappears after one day accompanied by a night of good quality sleep.<ref name="pmid17398311" />