Disruption to Biorhythms: Jetlag and shift work
- Created by: ava.scott
- Created on: 10-03-15 21:42
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- Disruption to bio rhythms
- Jetlag
- AO1 for jetlag:
- Jet lag is the extreme tiredness experienced after long haul flights over different time zones.
- It results in the temporary misalignment of the endogenous pacemaker, time zones and sleep wake cycle.
- SYMPTOMS: Sleep disturbance, cognitive ffects, fatigue, irritability, headaches, digestive problems.
- The discrepancy between your natural body clock and your social clock- the schedule you keep for your job and otehr commitments. You body is essentially going back and forth trhough timezones each day and week, resulting in sleep-deprivation
- PHASES
- Phase delay is when the cicardian rhythm is lengthed by the need to go to sleep later and wake up later.
- Phase advance is when the cicardian rythm is shortedned by the need to go to bed earlier and wake up earlier.
- Social jetlag
- The discrepancy between your natural body clock and your social clock- the schedule you keep for your job and otehr commitments. You body is essentially going back and forth trhough timezones each day and week, resulting in sleep-deprivation
- Jet lag is the extreme tiredness experienced after long haul flights over different time zones.
- Research evidence for jetlag:
- Klein
- Confirmed that flying west to east causes more jetlag than east to west. They did this by looking at flights from the UK to the US. and taking the passengers temperature-rhythm one day before theyb left, and then the 8 days after they arrived.
- Those who flew from US to UK could entrain more easily than those flying UK to US.
- One day per time zone crossed was needed for recovery.
- Grounding: Supports the idea that phase delayis easier than phase adance, as those flying west will have to stay up longer, and found this easier.
- evaluation
- Loads of different factors: Temperature of the place they have arrived may make a difference, food differences. Otherwise repeatable and reliable methodology.
- Confirmed that flying west to east causes more jetlag than east to west. They did this by looking at flights from the UK to the US. and taking the passengers temperature-rhythm one day before theyb left, and then the 8 days after they arrived.
- Sasaki
- Reported on the performance of the soviet union volleyball team after travelling the plan in japan. The team lost matches the first three days, but won by increasing margins over the next six.
- Sasaki said this was due to the re-entrainment of the soviet team to the japanese time zone
- Supports the theory as travelling east to west is difficult resulting in less wins. However entrainment lead to a increase in wins, as the players body cycles readjust.
- also shows jet lag is only temporary, so is less socially sensitive than shift work.
- Evaluation: There are other factors rather than just the cycle. New food, temperature, air quality, or just a new environment may have caused the fewer wins.
- Schwartz
- Found that american football teams travelling east to west had significantly more wins than those travelling west to east.
- Supports the thoery as the teams travelling west toe ast would have to phase advance by three hours, which is more difficult than ohase delay. Therefore their circardian rhytm would be more out of sync with exogenous zeitgebers than the EAST coast teams.
- Evaluation
- Low face validity- perhaps west coast teams are just worse at football.
- Different factors may effect.
- Low population validity- only looks at football players and the effects of jet lag on their performance in a game.
- O'Conner
- Looked at compe***ive swimmers
- Found no significant effect of jetlagtaht couldn't be described by lack of training.
- Doesn't support theory of an endogenous pacemaker, and that
- Klein
- AO1 for jetlag:
- Shift Work
- AO1 for shift work.
- Dirsupts the sleep wake cycle constantly because no adjustment can take place.
- Symptoms: increased cardiovascular disease, modo swings, accidents at work, family probolems, increased risk of cancer.
- Long term disruption which includes working irregular patterns e.g. night shifts
- IDA shift work
- Socially sensitive: Those being cared for at night, of offered a service, do not want to be at more risk. But shift work is often unavoidable.
- Socially sensitive: Shift work is often part of low-wage jobs, and this extra biological disruption would target the vulnerable (socio economically) even further.
- Those working night shifts don't want to be at risk from cancer, as some studies suggest they are.
- RESEARCH EVIDENCE for shift work
- Blakemore
- Studied chemical plant workers in Utah who worked 3 weekly schedules- first week a night shift, then an evening shifty and then a day shift.
- Found that animals subjected to the same schedule suffered great cardiovascular diseases and shorter life spans.
- Grounding: Agrees with the phase advance as a bad thing, because the animals and workers are having to shorten their cicardian rhythm as the weeks go on and this is more difficult than lengthening it.
- Evaluation: Small population validity- just Utah chemical plant workers.
- Evaluation: Use of animals is unethical.
- Cziesler
- Proposed that a shift pattern that went from day to night would be better. He tested this on the same chemical plant
- Found that workers felt less tired on the job and managers reported less incidents.
- Grounding: The study links to the explanation. It ios easier for us to adjust to a longer cicardian rhythm as or endogenous pacemaker is naturally 25 hours. This makes the research more compelling.
- Evaluation: Placebo effect- the workers believe the new schedule is better, so they feel better.
- Evaluation: Still a small sample size.
- Breast Cancer
- Fritschi
- 1000 women
- high population validity
- generalizability is good.
- men get breast cancer too!
- Hansen
- 692 women from the Danish Military
- Shift workers who considered themselves morning people had a 4x higher risk than woman who work during the day,
- Morning people find it more difficult to wake up later and stay up later, and so night shifts will be even more disruptive to their natural endogenous pacemaker.
- large sample size but of a small niche of people.
- Shift workers who considered themselves morning people had a 4x higher risk than woman who work during the day,
- Found a link, working night shifts is associated with a 40% increase in risk of cancer,
- 692 women from the Danish Military
- This is makes the research less generalizable to the whole public.
- Hansen
- high population validity
- No link between breast cancer and shift work
- 1000 women
- Hansen
- 692 women from the Danish Military
- Shift workers who considered themselves morning people had a 4x higher risk than woman who work during the day,
- Morning people find it more difficult to wake up later and stay up later, and so night shifts will be even more disruptive to their natural endogenous pacemaker.
- large sample size but of a small niche of people.
- Shift workers who considered themselves morning people had a 4x higher risk than woman who work during the day,
- Found a link, working night shifts is associated with a 40% increase in risk of cancer,
- 692 women from the Danish Military
- Melatonin has been found to effect other hormones involved in the growth of breast cells. Breast cancer sufferers have lower levels of melatonin, ansd shift work will suppress it further. This will cause the endogenous pacemaker to become out of sync with the exogenpus zeitgebers, resulting in poor sleep, and less restoration. This makes the stuidies more relevant, and not just assumptions.
- what about other cancers?
- Fritschi
- Blakemore
- WIDER EVALUATION for shift work.
- practical applications of research make *** more useful. We can change shift timetables to phase delay rather than phase advance.
- We can also support those who work in shift work in other ways to help reduce their chances of cancer/cardio vascular disease. e.g. by providing healthier food and gym memberships.
- AO1 for shift work.
- Jetlag
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