Shiftwork/Extended Work Hours and Health

Harrington (1978) concluded that the chronic fatigue, gastric and duodenal ulcers were common negative effects of shiftworkers. However, there was no evidence to support the correlation to increase mortality neither in shift workers nor for increased incidence of cardiovascular and neurological disorders. Harrington (1978) further stated that the task nature was associated with motivation and fatigue at the evening shift. For instance, workers suffered more fatigue for performing repetitive tasks than task required more mental effort at the night time. However, workers have difference response to shiftwork and the response to individual associated with physiology, psychology and the social environment on the individual.

1) Mortality

A study undertook in 1972 and the result indicated that there was no increase mortality for current shiftworkers. Waterhouse, Folkard & Minors (1992) claimed that from a research study in 1979, prolonged sleep loss associated with continuing shiftwork might adversely affect the mortality rates of workers. 
 
2) Cardiovascular Diseases

Waterhouse, Folkard & Minors (1992) claimed that the cause of higher incidence of cardiovascular disease in shiftworker is not confirmed but the shiftwork pattern of workers may correlated to the increase body mass, blood pressure, smoking, stress at work or blood lipid concentrations, decreased physical activity as well as disturbed body rhythms. Harrington (1994) stated that the link between shift work and increased cardiovascular morbidity and mortality has strengthened. 
 
3) Digestive Disorders and Ulcers

The possible effect of shiftwork to digestive disorders and ulcers might arise from the body clock. During the night work, the worker adjusts his/her body clock slowly and so there is a mismatch between the body’s physiology and biochemistry with the workers’ lifestyle. If the rhythm in gastric function is not adapted to night work, eating during the night might even exacerbate gastric problems (Waterhouse, Folkard & Minors, 1992).
 
4) Sleep Loss

There is considerable individual variation in the amount of sleep that people need but Waterhouse, Folkard & Minors (1992) suggested that shiftworkers loss of about two hours per day during night shift and during the morning shift, the loss depends critically upon the time at which the shift starts. This is also correlated to the individual workers attempts to maintain a social life the previous evenings. The accumulated loss of sleep during night shift gives concern of causing deterioration in performance and efficiency.

5) Others

Costa, et al. (2004) suggested that long work hours are linked to lower levels of health and well-being of the workers. Extended work hours have negative effects on stress, sleep and social and mental health. However, other company factors such as company and individual flexibilities on the extended work schedule demands, associated to the negative effect of extended work hours.

A study by Shields (2000) supported that females workers required to work extended working hours had increased odds of subsequently experiencing depression whereas for male workers, worked long hours experienced unhealthy weight gain. Both men and women experienced increased smoking habits and women experienced increased alcohol consumption.

Shift work/Extended Work Hours and Safety

Waterhouse, Folkard & Minors (1992) suggested that the there was negative correlation between the productivity or job performance accuracy with night shift but no clear findings were concluded the relationship between shiftwork and safety performance.

Previous research studies supported that individual is more fatigued on the night shift than during the day, and that fatigue reaches the maximum in the early hours of the morning after working in night shift and this is related to the occupational safety performance of workers (Waterhouse, Folkard & Minors, 1992; Dawson & Fletcher, 2001).

Dembe, Erickson, Delbos and banks (2005) concluded that workers required, routinely, to work overtime or extended hours increased the risk of suffering an occupational injury and illness. Similarly, Bourdouxhe & Toulouse (2001) provided that the technicians identified fatigue associated with extremely long work schedules as the major risk of accidents and also one of the factors responsible for causing or aggravating their many musculoskeletal injuries.
 
In addition, there is greatest relative risk of occupational injury and illness with requiring working extended with over to equal to 12 hours per day and extended to work over 60 hours per week in five day schedule. They further claimed that the risk of injury was found to increase with increasing length of work schedule with considering the longer absolute working hours at risk for injury. The result indicated that no matter the level of risk of the occupations and industries are classified, the result of extended working hours with increasing the injury risk is supported. The long working hours indirectly precipitate workplace accidents by inducing fatigue or stress in affected workers which results (Dembe, Erickson, Delbos & banks, 2005).

Evidence of poorer work performance and increased accidents especially for night shift workers, is supportive, however, the individual factors are strongly related to the result (Harrington, 1994). Hanecke et al. (1998) study shown that the percentage of accidents at different work hours is according to the particular time of day as well as when work is started. The result shows that the later starting times, the relative accident risk increased dramatically beyond the 8th hour at work.

Smith et al. (1998) concluded that there are few evidences to show the way of affect workers between eight and 12 hours shifts pattern. However, the evidence suggests that the advantage of 12 hours shift in terms of lower stress levels, better physical and psychological wellbeing, improved durations and quality of off duty sleep as well as improvements in family relations. The only negative side is the correlated to 12 hours shift to fatigue and safety. The inconsistent results can reflect that the accurate measurement the effects of long hours work are difficult to achieve consistently and this affected by individual factors, organization factors as well as the social factors of individual workers (Dalbokova, Tzenova & Ognjanova, 1995) . Spurgeon, Harrrington and Cooper (1997) proposed that a number of modifying factors are likely to influence the level and nature of health and performance outcomes of shift workers. The factors include the attitudes and motivation of workers concerned, the job requirements, and other aspects of the organizational and cultural climate.

In conclusion, the company is necessary to develop an appropriate work hours schedule to workers as so to minimize the health and safety effects of shift work and extended work hours to concerned workers. Kerin and Aguirre (2005) suggested that company who provide shift work lifestyle training also have lower rates of absenteeism and turnover compared to companies that do not provide training. In addition, if the employees are allowed to involving in the process of the selection of work arrangements, this will resulted that the workforce will experienced less fatigue, turnover and absenteeism and higher morale. The shift work and extended work hours are important elements on the human resources management and occupational health and safety management strategies.