7 Signs of Fatigue and How it Affects the Workplace

By Jessica Barrett
Last updated: December 11, 2018
Key Takeaways

Fatigue doesn’t just cause workers to feel more tired – it also increases the rate of accidents and injuries, reduces productivity, and causes absenteeism.

There are no specific OSHA guidelines around fatigue, but that doesn’t mean it’s not a significant workplace safety issue. Not only is fatigue a serious concern, it's also widespread. According to the National Safety Council, more than 43 percent of workers are sleep-deprived. Predictably, the problem is even worse for workers who do shift work or take the night shifts – 62 percent of them complain about sleep loss.


In this article, we'll go over what fatigue is, how you can spot it, and what you can do to help workers stay awake and alert.

Understanding Fatigue

Fatigue is more than just feeling tired. In fact, research shows that spending 17 hours awake is equivalent to having a blood alcohol content of 0.05, while 24 to 25 hours is equivalent to a BAC of 0.10. You would never let an employee operate heavy machinery with that much alcohol in their system, yet fatigued workers routinely engage in difficult or hazard-heavy work.


In the context of occupational health and safety, fatigue refers to mental or physical exhaustion that reduces one’s capacity to perform work safely and effectively. The causes, however, aren’t always just work-related. Some of the most common reasons for fatigue include:

  • Prolonged or intense mental or physical activity
  • Sleep loss or disrupted sleep
  • Travel
  • Organizational change
  • Irregular work scheduling or excessively long shifts
  • Strenuous activity
  • Long commutes to and from work
  • Extremely hot or cold work environments

Workers at high risk for fatigue include:

  • Shift workers
  • Night workers
  • Fly-in/fly-out or drive-in/drive out workers
  • Seasonal workers
  • On-call workers
  • Emergency service providers
  • Medical professionals and other health workers

How to Tell if a Worker Is Fatigued

Fatigued workers can put themselves or others at risk, so it's important for safety managers and supervisors to know the signs of fatigue. Here are some of the key things to watch out for.

1. Tiredness, Weariness, or Sleepiness

Dropping heads, incessant yawning, and eyelids that seem to be closing are the most obvious indicators that a worker is fatigued and needs time to recover before costly errors or accidents happen.

2. Irritability

Workers can be irritable for a number of reasons – problems at home, financial stress, conflict with co-workers – but one of them is lack of rest. It’s a good idea to watch for patterns of irritability or a newly developed "bad attitude," particularly when combined with other signs on this list.


3. Reduced Alertness, Concentration, or Memory

Watch for workers who appear to have trouble focusing or who can’t recall seemingly simple things, like what they just did or said. Having trouble solving problems can also be an indicator of fatigue.

4. Lack of Motivation

Employees who appear to all of a sudden lack motivation to do their job (and to do it well) may seem lazy, but it’s generally a sign of broader troubles, including fatigue (learn more about Managing Employee Burnout to Reduce Deadly Accidents).

5. Increased Mistakes or Lapses in Judgment

If a worker who has otherwise proven to be competent and good at their job starts making frequent errors or poor choices, it might be a sign of sleep deprivation or fatigue.

6. Headaches

Headaches are a sign of fatigue, but they can also be a sign of dehydration. Before chalking it up to fatigue, make sure all workers are adequately hydrated while on the job – even when they aren’t in hot environments (learn about The Dangers of On-the-Job Dehydration).

7. Increased Susceptibility to Illness

Workers who are suddenly taking more time off due to illness may be experiencing fatigue. Insufficient sleep wears the body down and affects its ability to fight off colds, flus, and other illnesses. With an increase in fatigue, it’s not uncommon to see a corresponding rise in absenteeism and sick days.

How Fatigue Affects the Workplace

Fatigue has very real, tangible effects on the workplace. The most concerning ones are an increased rate of accidents and injuries, a negative influence on decision-making, and lower productivity.

Increased Incidence of Injuries

The stats say it all. Compared to day shifts, accident and injury rates are 18 percent higher during evening shifts and 30 percent higher during night shifts. Research also shows that those who work 12 hours per day have a 37 percent higher risk of injury than those who work fewer hours. And the hazard risk continues even after work ends: a 2005 study of medical residents found that every extended shift scheduled in a month increased the monthly risk of a vehicle crash on the way home by 16.2 percent.

This increase in accidents and injuries often results from a perfect storm of factors, including reduced alertness, lower concentration, and impaired motor skills. The Journal of Occupational and Environmental Medicine found that workers who go 17 to 19 hours without sleep don’t just exhibit impaired performance levels, but have response speeds that are half as slow as well-rested workers. These fatigued workers also had worse hand-eye coordination, depth perception, and balance. This is particularly dangerous for those who work at height, use power tools, or operate heavy machinery.

Poor Decision Making

Research out of Zurich shows that a chronic lack of sleep leads to riskier behavior. Perhaps the most significant finding from the study, though, is that the participants deemed this behavior safer than they did under regular sleep conditions. In other words, when they were lacking sleep, workers didn’t even realize that they were taking greater risks. For fatigued employees, this could mean making impulsive and dangerous decisions without recognizing it – and it could also affect the health and safety of other employees, customers, or patients.

Lower Productivity

According to OSHA estimates, lost productivity due to fatigue costs employers a total of $136.4 billion every year. The high costs can be attributed to a number of different factors, including lower efficiency – as work hours increase, output and performance decrease – high injury and workers’ compensation costs, and greater absenteeism due to fatigue-related illnesses.

Proactively Addressing Worker Fatigue

Employees certainly play a role in preventing fatigue and some of the causes go beyond the workplace, but there are still a number of things employers can do to reduce fatigue at work. An effective approach to fatigue risk management should involve some or all of the following:

  • Shift scheduling: consistent schedules, frequent breaks, two consecutive days off each week, and no more than four night shifts in a row
  • Balancing workloads and staffing
  • Reporting system for fatigue-related incidents
  • Workplace design: cool atmosphere, low humidity, plenty of natural light, minimal noise and vibrations
  • Employee training on fatigue and managing sleep disorders
  • Supervisor and management training on monitoring and identifying fatigue in workers
  • Offering an insurance plan that covers sleep disorders


By identifying fatigue and taking proactive measures before it becomes an issue, you can ensure a safe, healthy, and productive work environment for your entire team.

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Written by Jessica Barrett

Jessica Barrett

Jessica is a freelance writer and editor from Toronto, Canada. She specializes in creating content for nonprofits and has written for organizations working in human rights, conservation, education, and health care. She loves traveling and food, speaks Spanish, and has two dogs, one of whom she rescued while living in Mexico.

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