Fatigue and Worker Safety

The American College of Occupational and Environmental Medicine defines fatigue as the body’s response to sleep deprivation or lengthy physical or mental hard work. Risk factors related to occupational fatigue include long work hours, a heavy workload, lack of sleep, environmental factors and medical conditions.

Even dealing with other people can result in fatigue, one researcher notes.

“You can be fatigued simply if you go to work and have really poor social interactions with your co-workers – it’s not just about how much sleep you get,” said Matthew Hallowell, associate professor of construction engineering at the University of Colorado Boulder.

Hallowell led a review of literature about causes and outcomes of occupational fatigue, which was published in the Journal of Occupational and Environmental Medicine in October.

Effects of fatigue can include slower reaction time, more errors and decreased cognitive ability. Fatigue can occur in all industries, but numerous studies have focused on its effects on shift workers, health care workers and drivers.

“The industries that are at highest risk would be those where people are working long hours, overtime, many days in a row, when they’re exposed to harsh environmental conditions, like working outside in the rain, snow,” Hallowell said. “Environmental conditions can include things like noise or vibration, really heavy mental task loads for long periods of time. You can extend to what industries that defines, like electrical transmission and distribution line workers, or people who drive snowplows.”

In addition, many people work multiple jobs, leaving them vulnerable to fatigue. People who work several jobs get 40 minutes less sleep per day than those who work one job, according to David Lombardi, principal research scientist at the Center for Injury Epidemiology at the Liberty Mutual Research Institute for Safety in Hopkinton, MA. Lombardi presented this data during the Dec. 13 “Fatigue Blue Ribbon Panel” in Chicago, hosted by the National Safety Council.

“Fatigue is an increasing health and safety problem in our daily lives due to the 24-hour society with decreasing emphasis on sleep,” Lombardi said.

Lombardi and researcher Simon Folkard, of the Université Paris Descartes, have published a risk index to estimate injury risk related to work schedules. Type of shift, number of consecutive shifts, hours worked per shift and rest breaks influence risk, Lombardi said. Risk was 31% higher among night shift workers than morning shift workers; by the fourth consecutive night shift, risk was 36% higher than on the first night, and risk nearly doubled by the 12th hour of work. However, injury risk decreased by nearly 50% after any length of rest break.

“An important message of our approach is that various features of a shift work schedule – beyond only working hours – need to be considered in combination when assessing the safety of a given work schedule,” Lombardi said.

The estimated annual injury incidence rate per 100 workers is 7.89 for U.S. workers who usually sleep less than five hours per day, compared with 2.27 per 100 workers among those who tend to sleep between seven and eight hours, according to research from Lombardi and others, using data from the National Health Interview Survey.

Fatigue Risk management Systems

Medical and lifestyle interventions, as well as work organization factors, can help promote alertness, according to a  American College of Occupational and Environmental Medicine guidance statement on fatigue risk management in the workplace. Organizations in which employees work long hours or at night – especially those with safety-sensitive jobs, such as in the energy, health care and transportation industries – can benefit from addressing fatigue.

ACOEM outlines the following key features of a fatigue risk management system:

  • Supported by peer-reviewed science
  • Decisions determined by data collection and analysis
  • Designed by stakeholders
  • System-wide use of tools, systems, policies and procedures
  • Constructed into the corporate safety and health management systems
  • Continuous improvement
  • Budgeted
  • Senior leaders take ownership.

Other critical elements include a safety management policy, risk management, reporting, incident investigation, training and education, and auditing.

Key defenses of a fatigue risk management system are:

  • Balancing workload and staffing
  • Shift scheduling
  • Training for employees on fatigue and managing sleep disorders
  • Workplace design
  • Monitoring of fatigue.

Although workers are responsible for being well-rested, managers should provide information, motivation and resources, ACOEM states.

In addition, workers should be educated about issues, such as fatigue-related hazards; sleep disorders; how to get adequate and quality sleep; how to recognize fatigue; the importance of diet, exercise and other health conditions; and alertness strategies, including designing workplaces with bright light, cool temperature, non-monotonous noise and low humidity.

Possible Solutions

Although workers can help prevent fatigue through measures such as taking breaks and adopting better sleep habits, employers also can help combat the issue.

A November report from RAND Europe, part of the nonprofit research organization RAND Corp., concluded that lack of sleep results in a 13% increased risk of death and the loss of 1.2 million workdays per year in the U.S. The report offers the following recommendations for employers:

  • Understand the importance of sleep and promote it.
  • Create brighter workplaces with settings for naps.
  • Deter lengthy use of electronic devices after work.