Focus on Fatigue

Effective Fatigue Management

By June 1, 2022 No Comments

Issue #74 – May 2022

Welcome to Focus on Fatigue!

A recent article, featured in Accident Analysis & Prevention, reviewed the effectiveness of Fatigue Risk Management Systems (FRMS). In this month’s Focus on Fatigue we feature this review, as well as considering the pros and cons of an FRMS in comparison to prescriptive hours of service rules.

We hope you find this issue helpful and informative.

The FRMS Team



Views expressed in articles and links provided are those of the individual authors, and do not necessarily represent the views of InterDynamics (except where directly attributed).

Effective Fatigue Management

Hours of Service Rules v Fatigue Risk Management Systems

Prescriptive hours of service (HOS) rules involve setting rules, such as maximum shift duration, minimum break duration and total work hours in a period, in order to manage fatigue.

Fatigue risk management systems (FRMS), on the other hand, are “a data-driven set of management practices for identifying and managing fatigue-related safety risks”¹. They are a tailored risk management- based approach involving multiple layers of defence (predictive, proactive and reactive). Let’s take a look at the pros and cons of both approaches.

Why not just set prescriptive hours of service rules?

While prescriptive hours of service rules may seem a simpler approach, there are a number of challenges with hours of service rules:

  • While HOS rules may be appropriate for managing physical fatigue “prescriptive rule sets are not well suited to managing the risks associated with mental fatigue”².
  • Not all hours are created equal! Prescriptive hours of service rules do not take into consideration circadian influence. “The relationship between shift duration and fatigue is critically dependent on time of day”², as is the effectiveness of recovery sleep.
  • Often with a focus on regulatory compliance, over reliance on prescriptive rules can occur with no real grasp on whether a system is actually safe.

Advantages of FRMS

An effective Fatigue Risk Management System can…

  • Allow flexibility to meet operational demand, while considering the risk context and remaining scientifically defensible.³
  • Be tailored to the particular job or industry and better consider the particulars of night time operations and other nonstandard work schedules².
  • Incorporate multiple layers of defence in the form of management practices that are predictive, proactive and reactive.
  • Involve continual improvement; assessing the effectiveness of the system and continuing to refine and improve the safety environment.

Challenges to FRMS

However, there can be challenges to implementing an effective FRMS.

  • FRMS implementation may be challenging in industries and organisations with limited resources.
  • A just safety culture is required for an FRMS to be effective.

A hybrid approach

Hours of service rules can work in conjunction with an FRMS. Some regulatory bodies are now opting for a hybrid approach; combining prescriptive rule sets with risk management-based approaches. Or providing organisations the option of aligning with strict hours of work controls, or alternatively implementing an approved risk-based approach to fatigue management.


  1. Sprajcer, M., Thomas, M., Sargen, C., et al. (2021) How effective are Fatigue Risk Management Systems (FRMS)? A review, Accident Analysis & Prevention,
  2. Honn, K. A., VAN Dongen, H., & Dawson, D. (2019). Working Time Society consensus statements: Prescriptive rule sets and risk management-based approaches for the management of fatigue-related risk in working time arrangements. Industrial Health, 57(2), 264–280.
  3. Dawson, D. & McCulloch, K. (2005) Managing fatigue: It’s about sleep, Sleep Medicine Reviews, 9, http://doi:10.1016/j.smrv.2005.03.002
  4. Gurubhagavatula, I., Barger, L., Barnes, C., et al. (2021) Guiding principles for determining work shift duration and addressing the effects of work shift duration on performance, safety, and health: guidance from the American Academy of Sleep Medicine and the Sleep Research Society, Sleep, 44(11), zsab161,

Recent Research

How Effective are Fatigue Risk Management Systems (FRMS)?

A recent narrative review in Accident Analysis & Prevention sought to answer the question “How effective are Fatigue Risk Management Systems (FRMS)?” While there was limited data available assessing the effectiveness of FRMS as a whole, the review was able to include 231 records looking at different FRMS components. The review found that “FRMS components (e.g., bio-mathematical models, self-report measures, performance monitoring) have improved key safety and fatigue metrics. This suggests FRMS as a whole are likely to have positive safety outcomes.” The review noted that “FRMS implementation may be challenging in industries and organisations with limited resources” and that organisational and worker commitment, workplace culture, and training, are crucial to the successful implementation of FRMS. The full article can be accessed through the above link.

Sprajcer, M., Thomas, M., Sargen, C., et al., (2021) How effective are Fatigue Risk Management Systems (FRMS)? A review, Accident Analysis & Prevention,

In The News

Social Dialogue towards a Positive Safety and Health Culture

Dr Manal Azzi, International Labour Organisation, 2022 

April 28 was World Day for Safety and Health at Work. This year’s theme was ‘Let’s Act Together’ to build a positive safety and health culture and focused on enhancing social dialogue. This video discusses the importance of social dialogue in promoting a positive occupational safety and health culture.

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