About 25 percent of the North American working population work shifts. Interest in the effects of shiftwork on people has developed because experts have blamed rotating shifts for the "human error" connected with nuclear power plant incidents, air crashes, and other catastrophic accidents. Many workers find that shiftwork disrupts their family and personal life, leading to health problems, including chronic fatigue and gastrointestinal disorders. Today, let’s discuss shiftwork safety.
What is shiftwork?
Shiftwork is common in workplaces where technical processes can only be interrupted without affecting the product or where expensive equipment is used more profitably when in constant operation. The overall prevalence of shift work is similar for women and men. However, there are gender differences in shift work patterns by type of employment. Many more women than men work in the healthcare industry, while many more men than women work in manufacturing and processing.
Alternating day, night, and afternoon shifts are common in:
• industrial work
• customs & immigration
• protective services – police, fire, ambulance
• hospitality – hotels, food service
• health care
• transportation services – trucking, airlines
Shiftwork and circadian rhythms
Many human physical functions follow a daily rhythm or a 24-hour cycle. These cycles are called circadian rhythms. Sleeping, waking, digestion, secretion of adrenalin, body temperature, blood pressure, pulse and many other essential aspects of body functions and human behaviour are regulated by this 24-hour cycle. These rhythmical processes are coordinated to allow for high and low activity during the day at night.
Typically, the body uses cues from its processes and the environment, such as clock time, social activities, the light/dark cycle, and mealtimes, to keep the various rhythms on track. For example, body temperature is highest during the afternoon and early evening (6:00 p.m.) and lowest in the early morning. If a person works at night, their body temperature does not vary much during 24 hours as usual. The temperature and other body rhythms get out of sync which can lead to feelings of fatigue and disorientation.
Some rhythms adapt in two to three days, while others change only after more extended periods. People adapt to new schedules at different rates, as do the different rhythms. A total reversal of circadian rhythms may never occur because most people go back to a "normal" day schedule on days off. Frequent changes in schedule and disruption to circadian rhythms can lead to chronic fatigue and other health problems.
Disruption of the quality and quantity of regular sleep is inevitable in shiftwork, particularly where night work is involved. Daytime sleep is seldom as deep or refreshing as night’s sleep. The problem is more significant if there is no quiet, dark, comfortable place to sleep. Even when disturbances are removed, a worker who returns home in the morning may still find sleep impossible or less refreshing. This difficulty occurs because the circadian rhythms are no longer synchronized. Being constantly tired is a typical complaint of shift workers.
Physical and mental implications of shiftwork
Gastrointestinal and digestive problems
Indigestion, heartburn, stomach ache and loss of appetite are more common among rotating shift workers and night workers than among day workers. Given the changes in the type and timing of meals, it is not surprising that the night worker is more likely to have a poorer diet. At night, losing appetite often increases snacking on "junk" food rather than a complete, well-balanced meal. Feelings of fatigue may encourage the consumption of beverages with caffeine (coffee, cola) to help the worker stay awake.
While cardiovascular disease has not been proven to affect shift workers more than others, heart rate and blood pressure have been shown to follow a circadian rhythm. The lifestyle of a shift worker can directly affect an individual's health. A shift worker must follow a good exercise program to maintain adequate fitness. It is also essential not to smoke, have good dietary habits, and participate in leisure activities.
Existing medical conditions
Workers who require prescription drugs to control certain disorders should be aware that disruption of the circadian rhythm can interfere with the medical treatment of some diseases. Check with your family physician and pharmacist if you take medication while working shifts.
Family and social life
Shiftwork interference to family lives, especially the time available to spend with spouses and children. This fact is very important since the amount and quality of social interaction are 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-shift workers. Participation in clubs, sports and other organized activities is difficult since they usually cater to the normal day schedule. A study also found that shiftwork is often “associated with considerable impacts on sleep, depressed mood and anxiety, substance use, impairments in cognition, lower quality of life, and even suicidal ideation.”
Safety and shiftwork
The Institute for Work and Health (IWH) reports strong evidence that night, evening, rotating, and irregular shifts are associated with an increased risk of occupational injury, “night, evening, rotating and irregular shifts all were associated with an increased risk of occupational injury or illness compared with regular day shifts.”
This risk is associated with worker fatigue, less supervision, and co-worker support during non-daytime shifts. One study reported that the night shift had the most incidents, followed by the afternoon shift and the least on the day shift. The risk of an incident was 20% more during the first to the second hour of a night shift, and a slight rise in incidents between 3 and 4 am. More incidents are reported on the 4th successive night shift than on the first night.
Shiftwork is not going anywhere, and your best line of defense is to incorporate healthy strategies to deal with this type of work. Next week, we will be discussing our top tips on how to manage shiftwork, so be sure to stay tuned.