by Nicholas M. Murphy
In today’s climate of downsizing, centralizing operations, and increased automation, we are assigning more responsibility to fewer people. We spend countless dollars on capital improvements in order to transform our plants into state-of-the-art facilities. We build centralized control rooms consolidating operations into one "nerve center" with fewer employees now responsible for monitoring more and more complex processes. This substantially increases the "net worth" of one employee’s performance. We recognize that these employees do not perform like machines, constant over the 24-hour day; rather their productivity, alertness, and mental performance rises and falls over the course of the day and night.
In this country, up to 23 million people work irregular shifts, with the majority required to work through the night shift. Many pharmaceutical companies are presently operating around-the-clock and even more are considering the option to increase production or to better utilize capital intensive equipment. It makes economic sense for capital intensive plants to operate continuously, even given the downside risks of night shift operations: decreased productivity, higher risk of accidents, and poorer product quality. Managers simply accept these facts and consequently maintain lower expectations.
For thousands of years, humans have awakened with the sun and slept at night. It has only been during the past century, with the advent of electricity and the electric light, that we have broken with what nature dictates. We are destined to be a 24-hour society even though human physiology intends us to be awake during the day and asleep during the night. Scientists have found that as a part of a precisely-timed, 24-hour repeating process (or circadian rhythm) a section of the brain sends out signals to many control centers in the body. This "body clock" manages such functions as core body temperature, hormonal release, and cognitive ability, as well as the wakefulness and sleepiness of an individual on a daily basis. We are awake and alert during daytime hours because our core body temperature is elevated, stimulating hormones, such as the growth hormone cortisol, are released, and brain activity is at its peak. Conversely, during nighttime hours, core body temperature drops, the sleep inducing hormone melatonin is secreted, and brain activity slows down, all in preparation for sleep. For the typical night shift worker the daily timing of these signals remains the same, even after years of work at night. In other words, the body does not adapt physiologically to wakefulness at night and sleep during the day.
One repercussion of this mismatch between the imposed work schedule and the "body clock" is that there is a rapid "weeding out" process in shiftwork. Those who remain are able to tolerate the struggle to stay awake through the night along with a reduced quality and quantity of sleep during the day. A typical night shift worker sleeps one or two hours less than a day worker, with the compounding effects that this daily sleep loss is cumulative. It therefore compounds the problem of maintaining alertness on subsequent night shifts. All in all, there remains a great potential for improvement of night time job performance and personal quality-of-life for the shiftworker.
Night workers are most susceptible to bouts of extreme sleepiness and the lack of ability to think clearly during the early morning hours (between 3 and 5 am). Night workers label this time the "bone zone" or "zombie zone". It is at this point that the potential for falling asleep or an error in judgment can result in anything from substandard quality product to a major industrial accident. Some of the most notorious industrial accidents (Three-Mile Island, Bhopal, Chernobyl, and the Exxon Valdez) occurred during these early morning hours with human error playing a key role in all of them. Years of laboratory testing demonstrates the severely diminished ability of the brain’s cognitive function during these early morning hours.
The Consequences of Working Out-Of-Sync With the Body Clock
Productivity is impaired.
Performing routine tasks becomes more difficult, reaction times slow significantly and judgment is diminished. Human errors at night are twice as frequent as during the day, and worker productivity has been measured to be as much as thirty to forty percent lower than during the day.
Safety is compromised.
Both the risk of employee accidents and the potential for industrial accidents increase. Workers are much more likely to fall asleep on night shift.
Personnel costs are higher.
Shiftworkers are more likely to suffer cardiovascular and digestive disorders. Shiftworkers also experience more frequent headaches, fatigue, stress, muscle pain, respiratory infections, and general malaise. These, in turn, result in higher rates of absenteeism, employee turnover, and the associated training costs.
Employee quality-of-life issues.
Studies have documented higher rates of divorce and suicide, as well as increased use of alcohol and drugs on the part of shiftworkers. Frustration, low morale, and diminished job satisfaction are also common among shiftworkers.
Over the years workers have developed tricks to merely keep awake on night shift. They will get up and take a walk or exercise, consume caffeinated drinks, eat high sugar foods, or interact with others. These are all temporary fixes, as none address the biological root cause, or physiological mismatch, between the work schedule and the human biological timing system.
Today’s typical industrial control room does not help matters. It is more aptly called a "monitoring" room where the operator sits in front of a group of computer screens waiting to respond to an alarm when the system gets outside preprogrammed parameters. Operators infrequently get up and move around the room, as they are monitoring the system and simply waiting for a problem to occur. Monotony can very easily set in. The operators can become sedate, thus magnifying the difficulty of remaining awake during the early morning hours. Compounding the problem, the rooms housing the control systems are typically kept dim in order to enhance computer screen visibility, and darkness promotes sleep. For the most part, the equipment maintains the process efficiently within preset parameters. However, it is possible for the process to stray outside the parameters, and this is when human interaction is paramount in averting costly equipment failure, bad batches, or even disaster. It is at this point your operators need to be at peak alertness, able to respond quickly and with mental acuity.
Research tells us that we are now able to control the timing of the body’s signals for sleep and wakefulness. This discovery was made by Dr. Charles Czeisler, Associate Professor, Harvard Medical School, and Director of the Laboratory for Sleep Disorders and Circadian Medicine at The Brigham and Women’s Hospital in Boston. Dr. Czeislers’ research found that light is the driving force in the timing of the body’s 24-hour clock. Light, through the optic nerve from the eye, travels a neural pathway to the brain and "sets the clock". Now, by "resetting the clock", through the use of precisely timed exposure to certain intensities of light (and darkness), we are able to transform nighttime performance into that of daytime. This is accomplished by shifting the position of the circadian rhythm to the appropriate time period to achieve natural alertness at night and natural sleep during the day.
ShiftWork Systems, Inc. (SWS) of Cambridge, Massachusetts designs and manufactures systems that capitalize on the biological effect of light and, is the exclusive worldwide licensee of this patented technology. SWS has developed the CiPET, Circadian Productivity Enhancement Technology system with several applications in various industries. The system consists of variable intensity, high-output light fixtures, an electronic controller unit, and software designed to calculate appropriate "lighting schedules" according to site variables such as the work schedule and individual preferences. To date, SWS has installed CiPET in control rooms, quality control labs, and supervisors’ offices in fossil and nuclear power plants, chemical processing plants and oil refineries, and at the Nuclear Regulatory Commissions Headquarters Operations Center. The NASA Space Flight Medicine Department has been utilizing SWS technology since 1990 to pre-adjust shuttle astronauts to varying launch times or split-shift crews. In all cases, sleepiness and fatigue on-the-job have been drastically reduced, while alertness, cognitive performance, and reaction times have been enhanced. Simultaneously, off-shift quality-of-life has improved for the shiftworker, with shiftworkers reporting better and longer sleep and improved family relations. Enhancements in worker productivity, efficiency, safety, and quality-of-life have been documented at the various installation sites. This equates to a safer, more productive work environment, along with a reduction in employee turnover and in absenteeism. Additionally, a system designed for clinical applications has been installed in a leading US research hospital.
SWS has developed a modular version of the CiPET system and is actively seeking clients aspiring to incorporate this state-of-the-art lighting technology within their organizations. We are seeking sites where operational integrity, safety and productivity are sensitive to human alertness and performance, as well as companies who wish to improve the quality-of-life for its workforce. If you are interested in improving productivity and workforce performance in your facility and consider your company to be a candidate site for an SWS Circadian Lighting Module³ application, we would be glad to discuss the potential benefits for your organization.
Page last updated: 5 March 2009