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Outline and evaluate the consequences of disrupting biological rhythms

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´╗┐Outline and evaluate research into the consequences of disrupting biological rhythms (16 marks, June 2011) Research into the causes of disruptions of biological rhythms, such as the sleep-wake cycle, have focused on the effects of shift work and jet lag. Researchers have found that disruptions in our sleep-wake cycle can result in both mental and physical health problems Jet Lag is also known as ?desynchronosis ?and it is defined as a temporary condition which is caused by travelling through several time zones within a short space of time. Symptoms of jet lag include tiredness, inability to sleep, nausea and indigestion. When we travel from east to west we gain time and this is phase delay. However when we travel from west to east we lose time and this is phase advance. Klein, Wegman, and Hunt?s (1972) ?Westbound flights? study found that it is easier to adjust our body clocks when travelling westwards due to phase delay. Recht et al?s (1995) ?Baseball? study found that teams travelling from the west coast to the east coast lost more games than teams travelling in the opposite direction of east to west. ...read more.


Rats have been found to have similar DNA to humans and many drugs have been tested on rats first before human trails therefore animal research may be reliable but there are still issues with how much we can extrapolate from animal research and to what degree it can be applied to humans. Research by Stewart and Amir is however supported by studies on flight attendants by Cho et al (2000) which found that regular, long-haul aircrew had raised levels of the stress hormone cortisol and performed less well than control participants on memory tests. A follow-up study in 2001 showed that more experienced female aircrew did not do as well on reaction time and memory tests than less experienced aircrew; again indicating the negative effects of cortisol on the hippocampus. Although the studies by Cho et al support the stress, the studies do not identify what is causing the stress, whether it is the flying itself or the occupation. Also individual differences such as the predisposition to stress have not been accounted and it could be that the release of the stress hormone cortisol was a result of the anxiety of taking the tests. ...read more.


Czeisler et al are the main researchers into shit work and its effects. They conducted a study in 1982 on a group of shift workers following a backwards rotating shift system who had previously reported a range of health problems. They discovered that it takes about 16 days to adjust to a new shift pattern and so proposed that the shift rotation period be changed from 7 to 21 days. They recommended that shifts should rotate forwards in time (phase delay) taking advantage of the body?s natural preference for a slightly longer than 24 hour cycle. The results of the changes were significant as workers reported liking the new shift schedules and enjoying better health; they also made much more productive use of their leisure time when not working. The changes were also positive for employers since there was an increase in productivity and decrease in errors that led to accidents. Criticisms of this research by Czeisler et al is that the works may have improved in productivity due to social facilitation and may have been exhibiting demand characteristics as they may have felt pressure to work better whilst being observed. Thus the results of the study may not be completely valid. ...read more.

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