Challenge Team Interim Report

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    Team Number: 009

    School Name: Andress High School

    Area of Science: Biochemistry

    Project Title: Sleeping Patterns and the effects on shift workers

Final Report


More than twenty-three million people work in the United States. Shiftwork has been part of their working environment since the invention of the light bulb. It has been incorporated into a number of industries and professions but only in recent times have we begun to look at its potential long-term health and safety hazards.

We intended to examine the physical and chemical aspects of how the body has difficulty adjusting to a diverse working schedule. We also researched the health and safety effects of the circadian system and the many social, psychological, and physical problems that shift work brings to the human body. Our plan was to see how shiftworkers can best cope with their shiftwork, and enhance their productivity. This project will help society by helping shiftworkers have a better understanding of how to regulate their sleep/wake patterns and have greater efficiency. Our team has chosen to do this project because it deals with many of the countrys important careers such as: doctors, nurses, firefighters, policemen, factory workers, and security guards.

As a team we interviewed shiftworkers, distributed questionnaires, and researched locations such as sleep labs, libraries, and other sources.

Background Information

Shiftwork is any system of working other than by regular day work. Shiftwork has not always been around until this past century with the invention of electricity and the electric light bulb. This has broken the routine of past centuries where the human awakens with the sun and sleeps at night. For reasons of plant or production needs, many people are finding that they are required to work at times traditionally set for rest or home life. As a result to this an estimated 20 to 25 percent of employees undertake shiftwork in a wide range of industries. Over this past decade this number, particularly in the manufacturing and service industries, has increased.


Shiftwork makes economic sense for capital intensive plants to operate continuously, even though there are the downside risks of night shift operations: decreased productivity, higher risk of accidents, and poorer product quality. This project can be applied to many business owners and managers so that their lowered expectations, because of these facts, can be raised. The efficiency of the workers will also raise as well as the companys productivity. In the long run this will benefit company owners, shiftworkers, their families and the community.

Rotating Shifts

Rotational shiftwork changes according to a set schedule with many shifts running continuously 24 hours a day 7 days per week, or semi-continuous running 2 or 3 shifts per day without weekends. Many workers take turns working on all shifts that are part of a particular system therefore leading to the problems that give the idea of shift work such a bad taste. Shiftworkers that work on the railway from 12 hour shifts for example, are forced into rotating shifts. Without any choice this causes the workers to have to take double shifts which leaves people with very little time off. It is in these situations where many workers begin to experience the problems that deal with social life and recreation which will complicate the status of their health, both mentally and physically. Therefore, most shiftworkers look forward to the possibility of slower rotations. This is better to work with, since a longer stretch of the same shift rather than the switching of time schedules which is more difficult. Rotating forward (Mid-Day-Eve) is thus considered the best method of improvement rather than rotating backward (Mid-Eve-Day).

Health Effects

Shiftworkers often work functioning on a schedule that is not natural, leading to an upset of the circadian rhythm to disorders of sleep deprivation, gastrointestinal complications, and a disruption of the cardiovascular system. The threat of night shift also brought further troubles to already existing problems that some workers had in turn disrupted family and social life.

Disruption of both the quality and quantity of a regular sleep pattern is impossible for most shiftworkers, particularly where night work is involved. Daytime sleep for those who work during late hours is almost never comparable to the deep and refreshing sleep that most have been accustomed to for many years. Difficulty to sleep throughout the day mainly comes from the many daytime disturbances and activities that keep those who try to sleep wide awake. Being constantly tired is a typical complaint of many shift workers due to the fact that the circadian rhythms are no longer synchronized since their sleep patterns are at a continuous change.

Also common among rotating shiftworkers and night workers are the gastrointestinal and digestive problems such as indigestion, heartburn, stomachache and loss of appetite. Unlike some day workers, night and rotating shiftworkers have also been assured to be more likely to suffer form peptic ulcers due to the improper care of sleep and eating schedules. Given the irregularity in type and timing of meals, it is not surprising that night workers are more likely to have a poor diet. With the exposure to junk foods and the consumption of beverages with caffeine the possibilities of shift workers being able to eat a full, well-balanced meal is a rarity.

Shiftwork is not absolutely associated with cardiovascular diseases. However, heart rate and blood pressure have been slower to follow a circadian rhythm. Since life-style can directly affect an individuals health it is very important that a shift worker follows exercise programs to maintain an adequate level of fitness. Those that work through the hectic schedules of shift work must also avoid smoking and must also produce good dietary habits. Although it may seem impossible for those on rotating shifts to include leisure activities into their daily routine it is very important that exercise be part of their lives.

Nevertheless, studies of Swedish men with a history of heart attacks, showed that they had been involved in some type of shiftwork throughout their life for a long period of time. Other studies also conclude that the forward rotations of shift work (Days-Afternoons-Nights) can significantly decrease the levels of several coronary risk factors for example: triglycerides, glucose, and urinary excretion of catecholamnes (adrenaline from bodily fluids).

Shift workers who are already suffering from an existing condition or disease should also be aware that the medication they take and the functioning of the circadian rhythm could aggravate their status of health. For employers with similar problems the help of a pharmacist is quite helpful in preparing a method where the time and schedule of work can correspond with the taking of medication.

As the complaints of shiftwork and its effect on health becomes more of a problem each day, other reports of its effect on family and social life has plagued spouses and their children to separations and even divorce. This fact is considered very important since the amount and quality of social interaction is related to physical and mental health. Individuals who cannot establish regular routines in their daily activities have difficulties planning for family responsibilities and coping with physical and mental fatigue as effectively as non-shiftworkers. Participation in clubs, sports, and other organized activities is very difficult since they are usually geared to the normal day schedule. The lack of regular social contact can lead to feelings of loneliness and isolation. In addition, quality child care facilities aimed at meeting the needs of shiftworkers is almost non-existent.

Safety, Strategies for Improvement, and Organizational Approaches for Shiftwork

Accidents tend to have many causes. There is usually no single factor to be considered. The disturbance of circadian motivation, and reaction time, specifically at night. This combination may result in increased risk of accident and injury. The lack of sleep heightens the downfall in performance normally experienced at certain times of the day. When a worker is deprived of sleep they are not fully aware that his or her performance has lessened. The optimum (most favorable) mental performance level for workers occurs between 2 and 4:00 p.m. and maximum general awareness is between 1 and 7 p.m. Performance levels are lowest between 3:30 and 5:30 a.m. It has been said that the solution to problems of shiftwork are not likely to be completely eliminated, but there practical strategies for improvement. Shiftwork is likely to continue to be a reality for a large percentage for many workers in Canada. Overall there are two basic levels where improvements can be made: One being the Organizational Level primarily through the design of shift schedules, education and better facilities. Secondly The Individual Level helping workers to get better sleep, a healthier diet, and the reduction of stress. One of the most common approaches to designing a more productive shiftworker is optimizing the arrangement of the shift schedule is the most effective way of reducing the health and safety problems. Circadian rhythms adjust better when moving ahead than back. It is recommended that shiftworkers rotate forward from day to night so they have an easier time adjusting. Facilities also have a role in the shiftworkers provision to cope. Good lighting and ventilation are important on all shifts. It is not advised to widely separate workstations so that workers at night can remain in contact with one another. Providing good cafeteria services so a balanced diet can be maintained is very helpful to shiftworkers. One thing that may be ignored through shiftworkers and managers is education on the potential health and safety effects rotational shiftwork and what can be done to stop these effects. In particular, education in stress recognition and reduction techniques is beneficial. It is also good to maintain regular eating patterns as much as possible. Afternoon workers should have the main meal in the middle of the day instead of the middle of the work shift. Night workers should eat lightly throughout the shift and have a moderate breakfast. In this case the shiftworker should not get too hungry while sleeping during the day and digestive discomfort should be minimal. Drinking lots of water and eating usual balance of vegetables, fruit, lean meat, poultry, fish dairy products, grains and bread help keep the shiftworker out of many of the digestive problems. It is better for the shiftworker to eat crackers and fruit instead of pop and candy bars during work breaks. It is good to reduce the intake of salt, caffeine, and alcohol. It is also a good suggestion to stay away from greasy foods, especially at night. It is also sensible that the shiftworker relaxes during meals and allow time for digestion. In the sleep category it is beneficial for workers to establish a routine and to make sleep during the day easier. Shiftworkers may try different patterns of work and sleep to see which is best for them. Having a comfortable, dark, quiet place to sleep during the day for the shiftworker ensues a better atmosphere for sleep and better sleep. There are also muscle relaxation, and breathing techniques that can help sleep and rest. Attention towards general physical fitness and good health habits should be kept. It is also wise for shiftworkers to take leisure seriously.

Team Members

Sponsoring Teachers

Project Advisor(s)