By Nicki Mandow
Saturday 1st June 2002
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Exxon Valdez, Chernobyl, three Tranz Rail crashes in four months in 2000. All, at least in part, were a product of fatigue in the workplace. But it's not just in major disasters where we see the dangers of lack of sleep, says Fiona Johnston, an occupational therapist and specialist consultant in sleep problems. Symptoms of lack of sleep include poor concentration, slow decision-making skills, mood swings, irritability, poor motivation, a drop in the body's defence mechanisms (leaving the worker prone to illness), working on "auto-pilot", sometimes even dropping off to sleep.
Some years ago Ford Motor Cars, together with the UK-based Universities of Aberdeen and Loughborough, conducted some telling experiments on drivers. One group of drivers was kept awake for 24 hours before driving a simulator for 40 minutes. During the first week of trials, nobody stayed fully awake until the end. One man fell asleep within five minutes, woke 40 minutes later and started to drive again. Afterwards he was convinced he hadn't fallen asleep.
Closer to home, coroner Peter Mahood criticised a Northland timber mill after one of its employees was killed in a road accident when he fell asleep driving home after working a 17-hour shift. Although the man had volunteered for the extra hours, the coroner concluded that employers are obliged to take all practical steps to prevent harm to employees in the workplace - including avoiding letting them get too tired.
In her book Getting a Good Night's Sleep: A Handbook for People who Have Trouble Sleeping, Johnston provides practical help for anyone with a sleep problem. Here are some tips from the recently revised edition:
What managers can do
Given particular circumstances - such as long hours of work, the time of day, the work environment and even the type of work - sleepy, fatigued workers can become a problem for all managers. Tired workers make mistakes, leading to a loss in production and health and safety concerns.
Improving shift work rosters:
Enlightened organisations that employ shift workers are taking heed of research into circadian rhythms and are implementing rosters that are compatible with the body's natural rhythms. Human beings are hard-wired to be awake during the day and asleep during the night. When we force our biological clock to tick at a different pace, we don't sleep for as long and the sleep quality is impaired. The result is a tired worker. In New Zealand most employers of shift workers encourage workers to remain daytime-oriented, thus causing minimal disruption to the body clock. This means limiting the number of consecutive night shifts so that the body does not start to adjust. The Occupational Safety and Health Service (OSH) recommends a maximum of three consecutive nights for 12-hour shifts, and four consecutive nights for eight-hour shifts.
Also important is the direction of shift rotation. Since our body clocks tend to run slow, at about 25 hours a day rather than 24 hours, a roster that rotates forward is less fatiguing than one that rotates backward. This means a day shift should be followed by a late shift, followed by night shift.
Interestingly, most shifts that are designed by staff rotate backwards because the amount of time off is perceived to be greater. Shift workers who have experienced both rotations usually report that the backward rotation is preferable at first, but after a few months it becomes very tiring and the quality of their time off deteriorates. Experienced shift workers usually prefer a forward rotation.
Some organisations require staff to work unreasonable hours that are bound to create sleep debt. In these instances, a taxi home provided by the company will eliminate the possibility of fatigue-related road accidents.
Train staff in fatigue management:
Some organisations that are prone to sleepy workers have implemented fatigue management programmes, in which staff are instructed in the nine points of alertness (defined in Johnston's book) and the most important fatigue management skill of all - keeping their sleep bank balance at zero.
Make the work interesting:
It's no secret that night work can be very boring, particularly in repetitive jobs like monitoring equipment or staring at a computer screen. Make work interesting by allowing staff to change jobs with each other or take regular breaks. Even a nap break may be beneficial for workers who may be fighting off sleep.
Manage the environment:
Bright lights in the work place, exercise equipment, access to radios and good air conditioning are all environmental factors that can be put in place to help the sleep-prone workforce. Meridian Energy, one of New Zealand's major power suppliers, addresses this problem by allowing its night crew to use an exercise cycle while working.
Getting a Good Night's Sleep: A Handbook for People who Have Trouble Sleeping by Fiona Johnston (Tandem Press, $24.95)
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