Mind Map by , created over 5 years ago

Mind Map on Jet lag, created by chloehathaway on 04/08/2014.

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Created by chloehathaway over 5 years ago
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Jet lag
1 What is it?
1.1 used to refer to the physiological effects of disrupted circadian rhythms. Our biological rhythms are not equipped to cope with sudden and large changes; it is estimated that the dorsal portion of the SCN takes several cycles to fully resynchronise to abrupt large changes in environmental time- a process we experience as jet lag. Winter et al 2002 calculated that this is equivalent to one day to adjust to each hour of time change. Symptoms include loss of appetite, nausea, fatigue, mild depression and insomnia.
1.1.1 The symptoms are thought to be caused by melatonin release being out of step with the new environmental conditions. Evidence suggests that melatonin supplement pills taken in the evening may reduce the effect of jet lag (Blackmore 1988)
1.2 Caused by travelling across time zones so quickly that biological rhythms do not match external cues, causing sleepiness during the day and restlessness during the night. This lasts until resynchronisation has occurred, it can take up to a week to fully synchronise to a new time zone.
1.2.1 Wegman et al found that travelling east to west (phase delay) seems easier to adapt to tan travelling west to east (phase advance). This is supported by Klein et al 1972 who tested 8 participants flying between the USA and Germany, and found that adjustments to jet lag was easier or people on Westbound flights than eastbound, regardless of whether they were on an outbound r homebound flight, supporting the fact that phase advance has more severe consequences.
2 Perfrmance decrement
2.1 Schwartz et al 1995 found that baseball sides from the eastern USA play better against teams in the west than western sides did playing againt teams in the east. This supports the ide that phase advance has more severe consequences. However, it may just mean that eastern teams are superior.
3 Dealing with the conseqeunces
3.1 Webb and Agnew 1971 found that successful strategies for coping with jet lag includes outdoor pursuits, expose to light ad regular mealtimes. This suggests that following exogenous zeitgebers is the best way to address the consequences of jet lag. However, there are indvdual differences; some people are more resistant to the effects of jet lag than others. This is known as phase tolerance.
4 Evaluation
4.1 Melatonin has been put forward as a miracle cure for jet lag and shift work. Because it is the natural hormone that induces sleep. Petrie et al 2001 reviewed 10 studies and found that where melatonin was taken near to bedtime, it was effective. However, if taken at the wrong time of the day if may actually delay adaption.
4.2 Social customs- this can help to entrain biological rhythms. E.g. when travelling, it helps to eat at the right time and go to sleep when the clock says it is time to go to sleep. Recent research suggests that a period of fasting followed by eating on the new time schedule should help entrain biological rhythms (Fuller et al 2008), possibly because some of our body clocks are reset by food intake.
5 Real world application
5.1 The importance of research on shift work and jet lag lies in the applications it has to our everyday lives, for example the use of artificial lighting to entrain and reset circadian rhythms. Being able to do this may help avoid disasters such as the Exxon Valdez.
5.1.1 The Exxon Valdez oil tanker ran aground at 12.04am in 1989 dumping more than 10 million gallons of oil into Alaska, and killing thousands of marine animals and sea birds. The Chernobyl nuclear power disaster began at 1.23am. Most lorry accidents occur between 4am and 7am. Moore-Ede 1993 estimated the cost of shift worker fatigue to be $77 billion annually as a result of both major accidents and ongoing medical expenses due to shift work-related illnesses.

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