Workplace Fatigue

Dr. Melissa Mallis, chief scientist for Operational and Fatigue Research in Baltimore, has some tips for dealing with workplace fatigue.

Who is most at risk?

Sleepiness is a challenge for workers, especially shift workers. Between 60 and 70 percent of shift workers report sleepiness at work or falling asleep on the job. Rotating shifts, being on call and working at night pose challenges to most.


The human body is designed to sleep during the night. This pattern is set by a small part of the brain known as the circadian clock. A shift worker confuses their circadian clock by working when their body is programmed to be asleep. Sleeping during the day is usually difficult, because the person's brain chemicals (neurotransmitters) are naturally set to 'wakefulness' mode.

Did you know?

Being awake for 17 straight hours may hinder performance, similar to having a blood alcohol level of 0.05%.

Poor workplace practices can add to a person's level of fatigue. These may include long work hours, hard physical labor, irregular working hours (such as rotating shifts), stressful work environment (such as excessive noise or temperature extremes), boredom, working alone with little or no interaction with others, or fixed concentration on a repetitive task.

How many activity breaks and rest breaks do you recommend for different periods of time?

There is no single formula. The important thing is to take more frequent breaks of shorter duration rather than the longer breaks after continuously being on duty. One NASA study showed that an hourly break of 7 minutes helped to increase physiological alertness and decrease physiological sleepiness. This was in pilots who were flying in an automated cockpit with little stimulation. An hourly break is common practice in some companies, but it is important for the individuals to get up and move around.

Rest breaks - in which a nap is obtained - can be taken at any time of the day, but if it's too close to bedtime, it can interfere with sleep. If using naps during rest breaks while at work, it is recommended that they be less than 45 minutes to minimize the effects of sleep inertia. Typically, these would be scheduled once per work shift.

What are some things you can do to maintain alertness?

  • Use a bright light
  • Activity breaks (i.e., getting up out of chair and walking around, stretching)
  • Postural changes - remain in upright position
  • No significant effects on alertness have been documented by turning up the radio, slapping face, rolling window down
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