Assess the impact of disrupted biological rhythms: The human body has the ability to adapt to changes or zeitgebers, as long as the changes occur gradually. When fast changes in zeitgebers occur the human bodily rhythms cannot adjust fast enough, this causes ill effects, ‘internal desychronisation’ One example of internal desychronisation is shift work. Shift work is defined as regular employed work outside the normal working day 7am- 6pm.
Research in to shift work says that it is both physically and psychologically damaging to peoples health to frequently suffer from internal desychronisation (Aschoff and Weaver). This is said to be because shift workers are being forced to adjust their natural sleep wake cycle to fit their schedules. Symptoms of internal desychronisation include, fatigue, headaches, impaired reaction time, and irritability. The effects on shift workers are important because of the high percentage of people that work shifts, 20% of people in the U.S work shifts. In today society it would be impossible to live with out shift workers, such as health workers, and industry workers.
Records show that more accidents happen at night than any other time. For example human errors of shift works at Chernobyl, which happened at 1.28 am. Also Three Mile Island happened at 4am these human could have possibly been avoided if more was known about shift work. Although these incidents could be due to other factors such as poor lighting and less staffing. Other evidence of the harmful effects of shift work include air traffic controllers who work rotated shift, they suffer from unusually high rates of hypertension and ulcers.
Jetlag is another example of internal desychronisation. Jet lag occurs when people travel rapidly from one time zone to another. This happens because of a mismatch between internal bodily rhythms stored from the last time zone and the effects of the zeitgebers of the new time zone. Symptoms of jet lag can include, fatigue, headaches irritability, constipation and reduced immune system. Jet lag has been found to be worst if travelling from west to east, this is because the natural body sleep wake cycle is 25 hours long not 24 like we work to, so the body finds it easier to adjust to a longer day rather than a shorter one.
Melatonin is said to play a crucial role in jet lag, after a long flight the cyclical release of Melatonin remains on the day/night pattern of the previous time zone for several days. In America a synthetic version of melanoma was marketed to combat jet lag, it has been shown to be successful in stopping the symptoms of jet lag in most situations if taken at the right time of day, although it is still banned in the U.K. The effects of Jet lag are said to be reduced if you follow the zeitgebers rather than your own body, i.e. changing your watch as soon as you get on the plane and eat and sleep according to that time.