There are two types of shiftwork. Fluctuating and non-fluctuating shiftwork differ in that in fluctuating shiftwork the worker’s shift is constantly changing. E.g., they will do an 11pm-7am shift one day, then the next day they will do 10pm-6am, etc. Non-fluctuating shitworkers do the same shift every night e.g., 12am-8am. Some noteable disasters, e.g. the Chernobyl and Three Mile Island nuclear disasters, occurred because those at fault had been shiftworking and were not alert enough to notice problems. Yet approximately 20% of workers in industrial countries shiftwork. This has some potentially threatening consequences on the safety of the workplace and of civillians and the environment.
It is estimated that approximately 20% of shiftworkers report falling asleep during work. This is particularly worrying for people such as lorry drivers, who could crash their vehicle and kill themselves and/or others. Apart from the disasters that could occur on the outside, internal problems also occur. Workers on night shifts have significantly higher rates of heart disease and diseases of the digestive system. Perhaps knowledge of this is not widespread – and makes the issue of shitworking an ethical issue. Take workers in underdeveloped countries such as Taiwan. There is already criticism of the exploitation of workers for low wages, but awareness has not been raised of the possible health problems these people may be suffering as a result of shitwork, and the consequences of this – maybe they will die earlier. This is even more unethical exploitation.
Czeisler et al (1982) came up with the idea of a phase delay rotation pattern, whereby the shift pattern rotates every 21 days in a forwards direction. Thus the worker’s schedule begins later in the day every 21 days. Czeisler had studied shiftworkers and argued that a phase delay rotation pattern brings increased benefits to workers end employers, e.g., health improvement, greater production and fewer accidents in the workplace.
Jet lag, also known as desynchronosis, is a condition in the short term caused by (usually air) travel across several time zones in a short period of time. The person’s internal pacemaker becomes out of synch with the external environment. When the person arrives in their new destination, external factors, i.e. exogenous zeitgebers, prevent their body from falling asleep or sleeping soundly. Such zeitgebers include sunlight and temperature as well as local timetables and the person’s social and work engagements. It may take several days for your body to acclimatise to the new time, as your body will feel tired at inappropriate times and wide-awake at other inappropriate times, e.g. in the middle of the night for the latter.
The main symptoms of jet lag are insomnia and tiredness. Other symptoms include constipation/ diarrhoea, dehydration, sweating, anxiety and increased susceptibility to illness. The worst affected people are those who travel from west to east, as they lose time and thus are pressed to stay up longer – hence the tiredness and insomnia effects. Those who travel from east to west gain time and so are better able to cope, although they are likely to be awake in the night, at least for the first night or two.
The potential problems of jet lag are less far-reaching than those of shiftwork because jet lag only usually affects people from time to time, when they travel, unlike shiftwork, which is part of their everyday life. Research could be done into how to resolve the symptoms of jet lag. One therapy that has been developed to try to reduce the effects of jet lag is light therapy, whereby light is shone through the back of a person’s knee, to adjust their rhythm to the appropriate time, making use of exogenous zeitgebers. Most critics have disregarded this therapy as not effective at all, however. The best thing to do is to just try to follow the timetable of the local people, i.e. go to sleep and wake up at a normal time in that timezone.
As shiftwork and jet lag are kinds of sleep deprivation, studies of sleep deprivation have relevence to it. Michael Siffre found that, after he spent 61 days, 205 days and three months under ground his body always reverted to a 24 hours and 30 minute cycle – i.e. technically it is an infradian rhythm rather than circadian. This supports the idea of phase delay rotation for shiftworkers and the idea that those with jet lag are better suited for travelling from east to west.