Circadian Rhythms & Shift Work

By Marisa Broughton
October 2000
Reprint Protection Officer News - Fall 2000

Circadian Rhythms, our internal biological clock, involves a system that regulates hormonal & brain chemical output and controls our sleep/wake patterns. When our "clock" is out of sync due to traveling across time zones or shift work, detrimental physiological and psychological problems such as social and family problems, sleep, stomach & gastrointestinal problems, along with depression and anxiety result.

Scientists such as Dr. Czeisler of Harvard University and institutions such as the Center for Design of Industrial Schedules in Boston, Massachusetts, The Mayo Clinic and Keyano College Lifestyle Services are just a few of those who have been studying circadian rhythms and shift work over the past decade. They have also concluded from their research that work related problems such as increased risk of accidents, slowed down productivity, poor job satisfaction, increased turnover and absenteeism rates also result from shift work and disruption to circadian rhythms.

Night shift is the time which is most problematic because it is when our body naturally wants to sleep. The hours between 3 and 5 am are at our sleepiest and least alert. Studies into the causes of disasters such as the Three Mile Island nuclear reactor incident, the Exxon Valdez accident, the Hinton Train Crash, Chernobyl and the space shuttle Challenger disaster were all found to be a result of human error. It should be noted that the errors occurred during a night shift. Further research has concluded that the underlying cause of the human error was fatigue and work schedules.

The problems commonly encountered with shift work are the same as those confronted by travelers crossing time zones. Czeisler estimates that it takes the body at least one week to adjust to an 8 hour time change. He suggests a three week shift rotation should be implemented to allow the body ample time to adjust to a shift change. Czeisler and other researchers have also agreed that it is easier for the body to adjust to a forward moving schedule rotation instead of a backward moving one. In other words, arrange the shift to move consecutively from days, to afternoons, to night shift.

Other suggestions to combat fatigue on the job, include physical activity such as stretching, getting up and walking around, engaging in an active conversation, writing and/or having a beverage that contains caffeine. Some offices and plants have purchased specialized lights that mimic daylight [San Diego Gas & Electric Co.], others [a hospital in Massachusetts] have adjusted shifts to always allow the worker some daylight [3 am - 3 pm, 3 pm - 3 am]. Both have experienced favorable results.

In productivity management today, we have learned to pay closer attention to the psychological & physiological well being of our work force if we want to achieve optimal results. A security officer's function involves a high level of observation, quick reaction, judgment and practical reasoning skills. To reach this level of mental performance, we need to be aware of factors such as circadian rhythms and proper shift management.

Bio: Marisa Broughton is President of Ayrmetes, a Security & Loss Prevention consulting company in Canada. She is writer, teacher and lecturer on the subject of Security & Loss Prevention. Marisa has also acted as a consultant and Security Coordinator for many celebrity appearances & events.