In 1986, Ms. Harnett was working for a large Canadian Railway company when one of their freight trains with over 100 cars drove into a passenger train, killing 23 people in the process. From that point on, Ms. Harnett has been studying the impact of fatigue on organizations, families, and society at large.
There have been several attempts made to define, identify, and measure fatigue in the workplace. The purpose of this paper is to separate fact from fiction, based on years of evidence based and scientifically supported research and not just anecdotal, unproven theories and technologies. The focus will be on a holistic approach to mitigating fatigue risk while defining the differences between risk management systems and risk assessments.
To begin with, there are several variations of the term "fatigue" itself. Many people consider fatigue, sleepiness, tiredness, and drowsiness as interchangeable terms when in fact, they are quite different from one another.
Fatigue is best defined as a decreased capacity to perform mental or physical work and is the result of inadequate restorative sleep.1 Fatigue builds in the body and the only way to rid the body of fatigue is through restorative sleep.
Drowsiness (or sleepiness) is a symptom of fatigue, demonstrated by a strong desire to go to sleep.2 This is important to distinguish, because drowsiness occurs in real time and can trigger an improper response on the job. For example, a person who is dis-engaged in their job because it is boring or tedious, will have a much higher risk for drifting off or falling asleep. But if we actively engage them in some way (maybe a cup of coffee, conversation, more stimulating task, etc.) then we can increase their alertness. This, however, does not mean that we have eliminated the fatigue that has been building up, and the more it builds, the more likely individuals will exhibit signs of drowsy behavior and elevated risk.