Focus on Fatigue

Issue #67 – January 2021

Welcome to Focus on Fatigue for 2021! We hope you have had a restful holiday period.

We thought we would kick of this year’s Focus on Fatigue by addressing a common question that we receive; “What is an appropriate fatigue tolerance level?” Unfortunately, it is not one that can be answered in a simple sentence. There are a number of factors that need to be considered when setting fatigue tolerance levels, which we will explore in this month’s feature article.

The FRMS Team



InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 7 3229 8300

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).


What is an appropriate fatigue tolerance level?

Fatigue is inevitable

There are many situations where fatigue is unavoidable; particularly when working across a 24 hour roster, which works against our natural circadian rhythm. This is why we talk about managing fatigue rather than eliminating fatigue. Managing fatigue requires a risk based approach involving a combination of interventions, including managing fatigue exposure, identifying risk, appropriate controls and appropriate fatigue training.

Fatigue tolerance levels

As users of FAID Quantum would be aware, FAID Quantum uses fatigue tolerance levels to assist in its reporting of hours of work related fatigue exposure. FAID Quantum allows the user to set a FAID Score and KSS tolerance level (or multiple tolerance levels). Desired compliance percentages can also be set. FAID Quantum provides reports specific to these settings. So, what is an appropriate fatigue tolerance level?

Task risk and other considerations

When using FAID Quantum, there is no standard fatigue tolerance level recommended. This is because there are a number of considerations when setting a tolerance level.

Not all tasks carry the same risks

Some tasks or roles are more sensitive to fatigue related impairment and/or have significant consequence in the event of a fatigue related error. For example, if someone working an admin role had a micro sleep at their desk, the potential consequences differ to that of a pilot having a micro sleep during final approach. Therefore, the level of fatigue exposure deemed acceptable in different roles may differ.

Controls/protections may be in place

Controls/protections may be in place to reduce the risks associated with fatigue for a particular task/role, impacting the fatigue exposure tolerated.

Fatigue scores are based on the average situation

Hours of work fatigue scores (KSS & FAID Score) are based on average exposure and opportunity for recovery sleep. Some environments may provide the opportunity for more (or less) rest and recovery sleep, influencing the tolerance level that is deemed appropriate. For example, workers living on site, with meals provided and other domestic tasks taken care of, have less commute time and less external time pressures than the average situation.

Workplace culture has a significant impact on the way fatigue issues will be handled by employees within an organisation. Organisational culture is often defined as “the way we do things around here” and is formed by a combination of beliefs, values and assumptions; all of which influence how people interact and behave.

Fatigue Hazard Analysis

To determine an appropriate tolerance level, we recommend an organisation carry out a Fatigue Hazard Analysis (FHA) risk assessment specific to their workplace and tasks. That is, a risk assessment which reviews the hazards of a role when fatigue is present.

Current hours of work fatigue exposure

The FHA risk assessment would consider, amongst other things, the current hours of work fatigue exposure which can be analysed using FAID Quantum. The apparent fatigue tolerance level reports (for KSS & FAID Score) provide an indication of the current hours of work fatigue exposure, most appropriately reflected when at least 6 to 12 months of the most recent actual hours of work data is analysed. It is often helpful for an organisation to take into consideration its current apparent tolerance level in setting a fatigue tolerance level. Until an organisation conducts a FHA, one option is to use the Apparent FAID Score Tolerance Level (FTL) & Apparent KSS Tolerance Level (KTL) as a rough guide. However, it is important to note, the apparent tolerance level does not necessarily represent a safe work environment.

The above apparent fatigue tolerance level reports from FAID Quantum show the current hours of work fatigue exposure of an organisation being at an Apparent FTL of 72 and Apparent KTL of 7.3.

Analysis of fatigue related data

For organisations that have collected fatigue related performance data, FAID Quantum provides the ability to investigate relationships between fatigue exposure (KSS & FAID Score) and the performance data, using the external results function. This may relate to safety incidents, but can also relate to other factors such as absenteeism, complaints or driver efficiency. You can read more here.

This data can provide insight to identify potential correlation between fatigue exposure and incidents. Such analyses can be helpful in determining appropriate fatigue tolerance levels for a particular environment.

Further reading

For further information about setting fatigue tolerance levels and what KSS & FAID Scores represent, you can read Establishing a Fatigue Tolerance Level.

In the News

Provided below are a selection of articles from around the web on the issues associated with fatigue. We hope you find them useful and interesting.

Video: What would happen if you stopped sleeping, day by day

Abby Tang & Andrea Schmitz, Science Insider, November 2020
“Why do we sleep?” has been a notoriously difficult question for scientists to answer, but, “What happens if we don’t?” is actually pretty simple — nothing good. Not getting enough sleep can make you hallucinate, mess with your thinking and memory, and even lead to organ failure. And it doesn’t take very long at all for these negative effects to start occurring. Here’s what would happen to your brain and body, day by day, if you stopped sleeping.

Article: Want your employees to be more productive? Make sure they catch those zzzs.

João Mendes-Roter, Entrepreneur, January 2021
According to the Centers for Disease Control and Prevention, more than one in three American adults fail to get enough sleep on a regular basis — jeopardizing their overall health while making them less productive, more error-prone and at higher risk of injury in the workplace. The annual cost to employers? Research indicates that it’s hundreds of billions of dollars.

Article: Sleep evolved before brains did, study finds

Rachael Rettner, Live Science, January 2021
Our brains need sleep to work properly. But it turns out you don’t need a brain to sleep. In a new study, researchers identified a sleep-like state in a tiny, freshwater animal called a hydra, which has a simple anatomy and lacks a brain.

Issue #66 – November 2020

Welcome to Focus on Fatigue,

We are fast approaching the end of the year, and this is the final edition of Focus on Fatigue for 2020. What a year it has been! Individuals and industries worldwide have seen major change – much of which has been hard, but we have also heard many identify elements of positive change that have occurred alongside the challenges.

As you journey towards the end of 2020, may you also be able to identify positive elements of change that have occurred for you this year.

In this edition of Focus on Fatigue, we are going to look at how workplace culture impacts fatigue management and how cultural change is often needed for effective fatigue management within an organisation.

The FRMS Team



InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 7 3229 8300

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).


Featured Article

“The way we do things around here”:
How workplace culture impacts fatigue management

Implementing an effective Fatigue Risk Management System (FRMS) is more than just a policy or IT project. It is a cultural change project.

Workplace culture has a significant impact on the way fatigue issues will be handled by employees within an organisation. Organisational culture is often defined as “the way we do things around here” and is formed by a combination of beliefs, values and assumptions; all of which influence how people interact and behave.

When theory and practice don’t align

Organisational culture is sometimes the elusive element to successful fatigue risk management. In many cases, explicit elements of organisational culture (such as policy and procedures) are at odds with implicit elements of organisational culture. Let’s look at a few examples.

A sense of camaraderie and genuine desire not to let colleagues down

In one study of metropolitan train drivers, “drivers expressed concern that leaving mid-shift would be letting their colleagues down and calling into question their ability to operate trains in the future. At the same time, drivers understood that this sentiment was also at odds with the directive of FRMS that required drivers to call in to be relieved when they were too fatigued to continue driving.”¹

This “research identified that drivers would often compromise their own rest opportunities and right to ask for relief because of a strong sense of camaraderie with their peers. Therefore, the cultural particularities of the workplace impacted upon the extent that FRMS could be fully adopted.”¹

Similarly, in another study of hospital nurses, a sense responsibility to their patients and obligation to their unit or team was identified as a barrier to their fatigue management.²

This culture of ‘having each other’s backs’ can simultaneously support and impede fatigue management.

A culture that encourages invulnerability

In some industries, such as healthcare and emergency services, there can be an unwritten expectation to ‘power through’ and portray an image of strength. In some cases, enduring fatigue can even be seen as a badge of honour.

The above mentioned study of hospital nurses, identified a ‘supernurse’ culture as a barrier to effectively managing fatigue and achieving a safety culture. Nurses in the study described “the importance of an appearance of strength. They also commented on a resistance in themselves or amongst their peers in asking for help”. Even when help was being directly offered, it was reported nurses were resistant to accepting it.²

A fear culture around reporting fatigue

A perception of potential negative consequences for reporting fatigue will impede effective fatigue management. In some situations, an employee may feel it will jeopardise future work opportunities or that addressing fatigue is discouraged at a supervisor or management level.

In order to effectively address fatigue, employees need to be able to manage fatigue and provide feedback without fear of repercussion.

A lack of genuine, accessible options

While fatigue management policies may be in place, the associated procedures may miss the mark on being genuinely accessible. For example, if you are expected to take a rest or nap break in your shift, but there is a lack of appropriate space for such a nap or inadequate staff to cover during the break. This is going to promote a culture of pushing through and foster the belief that management are not genuinely invested in fatigue management.

Use of informal strategies

In situations where formal fatigue management strategies may be insufficient or ineffective, informal strategies often emerge to manage fatigue.

One study of volunteer fire-fighters found that fatigue proofing behaviours existed, but they were not openly understood as such. “The study identified informal fatigue management behaviours at the individual, team and brigade level that have evolved in fire-fighting environments and are regularly implemented.” The study provided two recommendations: “(1) to identify and formalise current informal fatigue coping strategies as legitimate elements of the fatigue risk management system; and (2) develop culturally appropriate techniques for systematically communicating fatigue levels to self and others.” ³

Effective FRMS

Genuine concern from the top down

For the issue of managing fatigue risk to be taken seriously within an organisation, it requires a genuine concern to be evident from the top down. Modelled behaviour, systems and structures will all be looked to by staff to determine whether the issue is truly a priority in an organisation. Employees can tell if the issue of fatigue is approached as one of meeting minimum requirements, with little real concern for the issue; or whether the well-being and safety of staff, and ensuing economic benefits of an efficient and effective workforce are truly valued. How the issue is approached and FRMS are implemented will impact and shape company culture around fatigue.

Staff involvement

The above examples highlight the fact that staff engagement and consultation is key to a smooth FRMS implementation, as cultural change at all levels is often required for the organisation to transition its perceptions and management of fatigue in line with the organisation’s fatigue policy commitment.


These examples also highlight the importance of the ongoing review stage of an effective FRMS; to ensure that protection measures implemented are appropriate and effective.


  1. Rainbird, S., Thompson, K. & Dawson, D. (2010). The impact of organisational culture on fatigue management: The case of camaraderie amongst metropolitan train drivers. In: Sargent, C., Darewent, D. & Roach, GD (Eds). Living in a 24/7 world: The impact of circadian disruption on sleep, work and health, Australasian Chronobiology Society, Adelaide, Australia, pp. 29-33
  2. Steege, L. & Rainbow, J. (2017). Fatigue in hospital nurses – ‘Supernurse’ culture is a barrier to addressing problems: A qualitative interview study. International Journal of Nursing Studies, Vol 67, pg 20-28,
  3. Dawson, D., Mayger, K., Thomas, M. & Thompson, K. (2015). Fatigue risk management by volunteer fire-fighters: Use of informal strategies to augment formal policy, Accident Analysis & Prevention, Vol 84, pg 92-98,
  4. Gander, P., Hartley, L., Powell, D., Cabon, P., Hitchcock, E., Mills, A. & Popkin, S. (2011) Fatigue risk management: Organizational factors at the regulatory and industry/company level, Accident Analysis & Prevention, Vol 43 (2), pg 573-590,


InterDynamics News

InterDynamics have continued to successfully deliver FAID Quantum training and FRMS consulting via Internet video conferencing this year. If you have been considering FAID Quantum training or have any other FRMS related queries, we are happy to assist.


In the News

Provided below are a selection of articles from around the web on the issues associated with fatigue. We hope you find them useful and interesting.

Related Articles

Fatigue in air ambulance accident: What we can learn

Integrated Safety Support, August 2020
This week at ISS we’ve been talking about a positive development in the area of fatigue management – and that is a shift in culture towards trust and honesty.

Caledonian Sleeper told by own experts to ‘change culture’ over fatigue as next strike looms

Alastair Dalton, The Scotsman, October 2020
A “change in culture” over staff fatigue is needed at Caledonian Sleeper, according to experts drafted in to investigate the problem which has triggered a series of strikes.

Safety audit says ‘toxic workplace culture’ at Metro rail control center puts riders at risk

Will Vitka, WTOP News, September 2020
“Metrorail has not followed its own fatigue management policies that require at least one day off per week, has not addressed recurring safety issues, and has not implemented adequate recruitment, hiring and training practices,” the report states.

“I’ll Sleep When I’m Dead”: The sleep-deprived masculinity stereotype

University of Chicago Press Journals, Science Daily, September 2020
Men report getting significantly less sleep, on average, than women. A cultural complication is the notion that getting less than the recommended amount of sleep signals something positive about an individual.

Issue #65 – September 2020

Michael J. Fox once said, “Family is not an important thing. It’s everything!”  In this month’s Focus on Fatigue, we will explore the topic of work-family conflict and look at ways employers and employees can reduce the tension for shift workers and their families.

The FRMS Team



InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 7 3229 8300

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).

Featured Article

Shift Work and Work-Family Conflict

Work-family conflict occurs when the demands of work interfere, or are incompatible, with family life. By nature, shift work, or nonstandard work hours, present challenges to juggling work and family that differ from those experienced with standard work hours.

How can shift work have a negative effect on personal relationships?

Shift work has been found to have modest, but significant, negative effects on familial relationships in some circumstances. These include reduced marital quality and satisfaction, less or reduced quality time with children, increased risk of teenage delinquency, and an increased risk of divorce. A New Zealand study of shift workers who worked long hours in inflexible work schedules found that isolation could also pose a problem in shift worker families, not just for the shift worker but also for the non shift working partner.

Sleep deprivation is a major issue for many shift workers, and the research around this area can also provide insight into the detrimental effects of shift work on families. Studies have found that sleep deprivation is associated with feeling less gratitude towards partners, an increase in interpersonal conflict, reduced empathy and reduced emotional control.

Can shift work have benefits for personal relationships?

The news isn’t all negative, and shift work can indeed provide opportunities that standard hours of employment may not, such as alternative child care arrangements, providing opportunities to spend more time with children during the day, and the ability to attend school functions that might otherwise be problematic. It is certainly the case that some people prefer to work night shifts because those shifts fit in better with the individual’s lifestyle or personal requirements.

Addressing work-family conflict

The issues of work-family conflict relating to shift work are most effectively addressed when seen as a joint concern for both organisations and individuals and approached both through workplace and personal strategies.

What can employers do?

While shift work and nonstandard hours are unavoidable in many industries, research has shown that the following strategies can reduce work-family conflict and increase family time adequacy, as well as increasing job satisfaction and longevity:
– Provide work schedules with advanced notice
– Offer stability in work schedule
– Offer workers greater control over scheduling
– Provide shift work training that includes family involvement and social coping strategies
– Promote a supportive culture that is reflected in policies, practices and supervisor support

What can shift worker families do to strengthen their personal relationships?

What are the most effective strategies shift workers, and their families, can use to ensure that their personal relationships are at an optimum? Unfortunately the research hasn’t yet extended as far as providing evidence-based answers to this very important question. Of course, many shift worker families use a variety of strategies that enable their family to function effectively. For those who would like a few extra hints and tricks, the following strategies have been recommended by researchers in the area:

United we stand

Maintaining a strong family unit in the face of shift work challenges is, partly, about attitude. Every member of the family must be willing to work together and make compromises when necessary. It is impossible for a shift worker to slip into the normal routine of the non-shift working family the moment they walk in the door. It is just as impossible for the non-shift working family members to arrange their lives entirely around the needs of the shift worker. This is not because the different members of the family aren’t trying hard enough, it’s just because they’re out of synch with each other. If everyone works together, perhaps the family can find ways for these two disparate routines to complement each other, instead of clashing head-on.

Recognising mood swings for what they are

As mentioned previously, sleep deprivation lowers people’s emotional stability. We get grumpy, we’re more easily irritated by little things, and we don’t always appreciate our loved ones as much as we would if we were well-rested. If a shift worker comes home from a long night shift and is grumpy, this is not because their personality has changed or because they love their family less, it’s because they need sleep. After they have slept, chances are they’ll revert back to their usual selves. The same is true for anyone who has gone too long without sleep. Recognising these sorts of minor mood swings for the temporary phenomenon they are can help family members understand what’s happening when they occur.

Planning ahead

Many shift work families talk about the importance of The Family Calendar! This is the big planner that hangs on the wall and tells everyone where everyone else is going to be. Shift times will always be the first thing the shift worker adds to the family calendar. This gives other family members an idea of when they may be able to plan time with the shift worker, even if it’s simply having a meal together as a family.

Prioritise sleep

Sleep deprivation is one of the greatest challenges facing shift workers. A lack of sleep will affect every other aspect of a shift worker’s life and, by extension, the whole family. Therefore, it is essential that after shift times are added to the family calendar, sleep times are added next. It is imperative that the family work together to protect these sleep blocks from interruption. The shift worker can ensure they are using good sleep hygiene to increase the chances of getting good quality sleep. Other family members can arrange to either be out of the house at those times, or to keep noise levels to a minimum.
A solid schedule of sleep blocks also provides reassurance for family members regarding the times they can freely make noise without interrupting the sleep of the shift worker. After all, it’s their house too and no one can be quiet all the time.

Making time for each other

After the shift roster and sleep blocks have been added to the family calender. What comes next? Family time, of course. No family can maintain strong relationships without spending time together. This includes time as a family (if children are present) and time as a couple. Quality will generally be more important than quantity. As a couple, it may be necessary to put aside two periods of time where possible. One for talking about household issues such as finances, why the lawn hasn’t been mowed, and the leaky tap in the bathroom. The second for relaxing and enjoying each other’s company.

Making time for me

Everyone needs time away from both work and family in order to maintain their individual sense of self. This may be solitary time for reflection, or it might be time catching up with friends. It may involve participation in a hobby or just reading a good book. Every member of the family in entitled to some time alone, or with friends, both those who are working shifts and those who aren’t.

Communication is key

On a practical level communication can be as simple as making sure everyone knows the roster of the shift worker, and the schedule of everyone else in the household. A shift working parent can’t attend their child’s football game, even if they’re available, if they don’t know it’s on.
On an emotional level, communication is all about checking in with each other. This can include texting during a break or leaving notes for each other. Get creative! For example, draw some simple graph lines on a small whiteboard and hang it in a well-used area of the house. One axis on the graph could indicate energy levels, ranging from ‘exhausted’ to ‘bouncing off the walls.’ The second axis could indicate mood, ranging from ‘everything is awful’ to ‘everything is awesome.’ Each family member has their own magnet to place anywhere on the graph to indicate their present emotional state. For example, Mum might be feeling a little tired (moderate on the energy scale) but she’s happy she accomplished everything she wanted to do today (high on the mood scale). This is a simple concept that can allow each member to tell others in the family how they’re doing, and when they need extra support, without having to say it in words.

When it all goes wrong

Adding shifts to the calendar, adding sleep to the calendar, making time for family, for spouses, for the individual. And don’t forget to find time to wash the dog! Put all this together and it can feel like you need 30 hours in every day just to fit it all in. This, of course, is where compromising comes in. Most people find it impossible to do everything they need to do all the time, whether they are shift workers or not. Therefore, when schedules clash, plans go out the window and the dog is still covered in mud, it will be necessary to be okay with life not working for a while. Throw your hands in the air. Move your magnet to the ‘life is awful’ part of the graph. Laugh. Give each other hugs, even if it’s in the moment before you charge out the door on the way to your next shift. Then try again tomorrow. After all, family is what life is all about!


  • Davis, K. D., Goodman, W. B., Pirretti, A. E. and Almeida, D. M. (2008) Nonstandard work schedules, perceived family well-being, and daily stressors. Journal of Marriage and Family, 70(4), 991-1003.
  • Gee Wilson, M., Polzer‐Debruyne, A., Chen, S. and Fernandes, S. (2007), Shift work interventions for reduced work‐family conflict, Employee Relations, Vol. 29 No. 2, pp. 162-177.
  • Gordon, A. M. and Chen, S. (2013) The role of sleep in interpersonal conflict: Do sleepless nights mean worse fights? Social Psychological and Personality Science, 5(2), 168-175.
  • Handy, J. (2015) Maintaining family life under shiftwork schedules: A case study of a New Zealand Petrochemical Plant. New Zealand Journal of Psychology, 39(1), 29-37.
  • Hendrix, J. A. and Parcell, T. L. (2014) Parental nonstandard work, family processes, and delinquency during adolescence. Journal of Family Issues, 35(10), 1363-1393.
  • Kelly, E. L., Moen, P., Oakes, J. M., Fan, W., Okechukwu, C., Davis, K. D., Hammer, L., Kossek, E., King, R. B., Hanson, G., Mierzwa, F., & Casper, L. (2014). Changing Work and Work-Family Conflict: Evidence from the Work, Family, and Health Network. American sociological review, 79(3), 485–516.
  • Monk, T. H. and Folkard, S. (1992) Making shiftwork tolerable. Taylor & Francis: London, UK.
  • That, Kadri and Mills, Melinda (2016) Out of Time: The Consequences of Non-Standard Employment Schedules for Family Cohesion. Springer Briefs in Sociology: London, UK.
  • Vaghar, M. I., & Masrour, M. J. (2019). A comparative study of satisfaction and family conflicts among married nurses with different working hours. Journal of family medicine and primary care, 8(2), 472–476.
  • White, D. (2018) Shift work and relationships. Psych Central. Retrieved on August 5, 2020, from
  • WorkCover (2020) How to manage shiftwork: Workcover NSW health and safety guide. WorkCover NSW: Gosford, NSW.


In The Research

Shift work interventions for reduced work-family conflict

Marie Gee Wilson, Andrea Polzer-Debruyne, Sopie Chen, Sonia Fernandes (2007)
Employee Relations, Vol.29 No.2, pp.162-177.


Purpose – This research aims to investigate the efficacy of family involvement in shift work training targeting both physiological and social coping strategies.
Design/methodology/approach – The study utilized repeated surveys of work-family conflict (WFC) and family-work conflict (FWC) in a naturally occurring field experiment. Three small process manufacturing sites introduced training for shift workers, with or without family involvement, and with or without training on managing relational aspects of shift-work.
Findings – The inclusion of social coping strategies combined with family involvement significantly reduced work-family conflict. Open response categories on the survey suggest that these reductions were due to the facilitation of a joint problem solving approach by family members. In contrast, employee focused training on physiological coping alone appears to increase family conflicts.
Research limitations/implications – As a field study, this paper cannot control for the particularities of family situations. It should also be noted that the participants were all male, and results may have differed for female shift workers given differing family and work expectations.
Practical implications – For employers and OSH officers, this research suggests that broader spectrum training may assist shift workers in managing the requirements and impact of unsociable hours of work. For the shift worker, the research reinforces the importance of family support and family involvement in moderating shift work’s potentially negative effects.
Originality/value – This is the first study to assess the impact of family involvement in training and development-based interventions. This paper provides a unique perspective on shift work interventions by documenting both content and process effects for shift work support.

In the News

Provided below are a selection of articles from around the web on the issues associated with fatigue. We hope you find them useful and interesting.

Related Articles

Why 9 to 5 isn’t the only shift that can work for busy families

University of Washington, Science Daily, June 2018
For the millions of Americans who work “nonstandard” shifts — evenings, nights or with rotating days off — the schedule can be especially challenging with children at home. But a new study from the University of Washington finds that consistent hours, at whatever time of day, can give families flexibility and in some cases, improve children’s behavior.

Unpredictable work hours and volatile incomes are long term risks for American workers

Katherine Guyot and Richard V. Reeves, Brookings, August 2020
Debates about working time tend to focus on quantity. Are American workers having to put in too many hours, especially those with caring responsibilities? This is of course a vitally important question. But it is not the only one. It matters not only how many hours people work, but how much control they have over them.

Recent Studies Relating to Sleep and Fatigue

Optimistic people sleep better, longer, study finds

University of Illinois at Urbana-Champaign, News Bureau, Science Daily, August 2019
People who are the most optimistic tend to be better sleepers, a study of young and middle-aged adults found.

Bad sleep can cause migraines two days later, new study finds

Abby Moore, Mind Body Green, December 2019
For the one in seven people who suffer from migraines, that inability to fall asleep can have even worse effects, according to new research.

Smelling your lover’s shirt could improve your sleep

University of British Columbia, Science Daily, February 2020
The scent of a romantic partner can improve sleep, suggests new psychology research.

Having trouble sleeping? Try forgiving someone

Sophie McMullen, The Washington Post, October 2019
You may have tried a bedtime meditation or a technique such as the military method to help you fall asleep, but according to a study published last month in the Journal Psychology and Health, there’s another practice you could consider instead: forgiveness.

Issue #64 – July 2020

Welcome to Focus on Fatigue!

While some workplaces have slowed down in recent months, here at InterDynamics we have been working hard on the latest version of FAID Quantum. In this month’s Focus on Fatigue we introduce you to FAID Quantum v1.1 and its new capability. We will also look at some of the potential, measurable impacts that fatigue can have in a workplace.

The FRMS Team



InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 7 3229 8300

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).

InterDynamics News

New Version FAID Quantum

We are pleased to announce that InterDynamics are releasing FAID Quantum v1.1. This new version includes an exciting new feature allowing external results data to be imported and reviewed in conjunction with predicted FAID and/or Karolinkska Sleepiness Scale (KSS) Scores at that time.

This allows the possibility of analysing data and reviewing if fatigue is a factor relating to events such as: accidents, incidents, errors, near misses, excessive braking, complaints, absenteeism or sick leave.

This analysis can play an important step in developing a Fatigue Risk Management System and assist in informing an appropriate fatigue tolerance threshold for different tasks and environments.

The external results feature also allows external measures of fatigue, such as self-reported KSS and PVT results, to be analysed against predicted KSS and FAID Scores to review correlation.

Some of the ways that this capability has already been put to use are featured in the below article.

Featured Article

Impacts of Fatigue in the Workplace


The dangers of fatigue in the workplace in relation to safety are well recognised and shown in many studies. Here is one example where an organisation has used a large data set of incidents and analysed this data against hours of work fatigue scores, using FAID Quantum. An increasing trend of incident rates (incidents per million hours worked) was identified with increases of FAID Scores beyond 40 and KSS Scores beyond 7.While much of the discussion around workplace fatigue focuses on risk of incidents and injury, safety is not the only concern when it comes to workplace fatigue. The other effects of fatigue in the workplace may be more subtle and sometimes go unnoticed or unacknowledged. However, they can still have a considerable impact on an organisation.


One study¹, using FAID Quantum, looked at U.S. police rosters and found a correlation between fatigue and public complaints. The study concluded that “greater predicted fatigue and sleepiness levels, and reduced 24 hr sleep estimates increased the odds of a public complaint against an officer. Consecutive night shifts increased predicted fatigue, reduced 24 hr sleep estimates and increased odds of a public complaint against an office. Off-duty court hours further restricted sleep estimates, further increased predicted fatigue, and further increased the odds of a public complaint.”


Another recent study², using FAID Quantum, looked at U.S. police officers and absenteeism. This study found that greater predicted sleepiness was associated with higher odds of absenteeism the next workday, in particular for afternoon and night shift workers. Absenteeism has a flow on impact on an organisation through staff shortage, management time, lost productivity and decreased morale.

Driver Efficiency

In examining the effects of fatigue on train drivers (loco engineers), one study³ found a significant correlation between predicted fatigue scores and fuel use. Drivers in the moderate fatigue group used 4% more, and drivers in the high fatigue group used 9% more fuel than drivers in the low group. Therefore the cost of fuel significantly increased when using high fatigue drivers. The study further found that high fatigue drivers engaged in more heavy brake and maximum speed violations. These variations in the high fatigue group represent a reduction in planning, efficiency and safety.

Developing a Fatigue Risk Management System

The potential impacts of fatigue in a workplace are far reaching. Identifying and understanding where fatigue may be impacting your business is one step in developing an appropriate Fatigue Risk Management System. You can read more about InterDynamics Risk-Based Approach to Fatigue Management here.


1. Dawson, D., Riedy, S & Vila, B. (2019), US Police Rosters: Fatigue and Public Complaints. Sleep, Volume 42, Issue 3,

2. Riedy, S., Dawson, D., Fekedulegn, D., Andrew, M., Vila, B., and Violanti, J. (2020), Fatigue and Short-term Unplanned Absences Among Police Officers, Policing: an International Journal,

3. Dorrian, J., Hussey, F., & Dawson, D. (2007) Train Driving Efficiency and Safety: Examining the Cost of Fatigue, Journal of Sleep Research, Volume 16, Issue 1,

Provided below are a selection of articles from around the web on the issues associated with fatigue. We hope you find them useful and interesting.

For Further Consideration

Work-related Fatigue and Job Design
Dr Carmel Harrington and Professor Drew Dawson, Safe Work Australia, 2016
In this seminar, Dr Carmel Harrington and Professor Drew Dawson examine why fatigue management is important from both a worker and a business perspective and what businesses and workers can do to manage the risks caused by fatigue in the workplace.

Fatigue Risk Management in the Workplace
ACOEM Task Force on Fatigue Risk Management, Journal of Occupational and Environmental Medicine, 2012
The purpose of this article is to provide information to assist OEM physicians in these roles. It is designed to provide background, key concepts, and references needed to promote and support an FRMS.

In the News

We’ll be challenging the rail industry – regulator speaks out on fatigued worker death
Ian Weinfass, Construction News, 10 June 2020
Railway contractors should prepare to be challenged over how they manage workers carrying out dangerous tasks while on long shifts.

Issue #63 – May/June 2020

Welcome to Focus on Fatigue!

It is a time of change for most of us – whether suddenly finding ourselves at home more than usual, or in a work environment with added stress and strain. In some way, we have all had changes to our normal routine recently.

While it may feel like there are many things we can’t control at the moment, let’s look at what we can control. In this month’s Focus on Fatigue, we are going to get back to basics and look at good sleep habits to support us through this time and give ourselves the best chance of a good night’s sleep.

Stay safe!

The FRMS Team



InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 7 3229 8300

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).

Featured Article

Back to Basics – Good Sleep Habits

Sleep plays an important role in immune functioning, emotional regulation and overall health – things we all need at the moment!

However, between the significant changes to our normal routines along with added stress and worry, many of us may be finding it even harder than normal to switch off and fall asleep.

So what simple steps can we take to encourage our bodies to fall asleep, stay asleep and achieve good quality sleep?

The Sleep Health Foundation of Australia has listed the following practices as important for a good night’s sleep:

1. Try to go to bed at the same time each night

This one is not going to be possible for shift workers who are sleeping at night one week and during the day the next. However, if you are working a long block of consecutive shifts, then it may be helpful to try to go to bed at the same time each day.

2. Have a relaxing pre-bedtime routine

This ‘wind down’ time can include activities such as a warm bath or shower, reading a book (a paper book that is, not an electronic book), listening to music or having a cup of herbal tea. If you find yourself struggling to switch off your thoughts, perhaps set aside a ‘worry time’ earlier in the evening to reflect and plan and then set these thoughts aside until the next day.

3. Avoid caffeine for at least 4 hours before bed

One study found that caffeine consumed as much as six hours before bedtime can have detrimental effect on sleep.

4. Avoid smoking and alcohol before bed

Cigarettes and alcohol have both been found to impair sleep quality. They can also make some sleep problems, like snoring and sleep apnoea, worse.

5. Avoid using electronic devices, especially computer tablets, smart phones, etc. in the hours before bedtime

Melatonin is a hormone that helps our bodies recognise when it is time to go to sleep. Blue light, which is emitted by our favourite electronics, suppresses our secretion of melatonin. Additionally, stimulation from electronic devices doesn’t help the brain to wind down. So, if you want to sleep peacefully, you’ll have to kick that smart phone out of the bed.

6. Don’t go to bed on an overly full or overly empty stomach

Hunger can keep anyone awake, but then so can a stomach that is hard at work digesting a big meal. Be sure to eat a few hours before bedtime. If hunger does strike, a light snack or a glass of milk is better than something heavy.

7. Sleep in a room that is comfortable, including temperature, bedding, dark and quiet

Get comfy! You’re most likely to be lulled to sleep with a warm blanket in a cool room. Ear plugs and block-out curtains can be helpful to keep out noise and light if you are a shift-worker trying to sleep during the day.

8. Keep the bedroom for sleep and intimacy only

Experts believe that going to bed should be a signal to the brain that it is time to go to sleep. Therefore, using the bedroom for activities other than sleeping and intimacy, such as watching television or eating, is discouraged.

9. If you can’t sleep within 20-30 minutes of going to bed, get up and do something relaxing until the next wave of sleepiness hits. Then go straight back to bed.

Anxiety and frustration can be experienced when you spend too long staring at the ceiling, which can have a negative impact on your chances of falling asleep! If you are still awake after 20 minutes, it’s time to get up and do something relaxing (such as reading a book) before trying again. Be sure to keep the lights dim!

10. Morning light and exercise

Being out in natural daylight, especially in the early part of the day, helps to regulate your body clock and melatonin levels in the body. Exercise has also been linked to improved sleep. So, getting out for a morning walk may well be beneficial to night time sleep.


  • Drake, T., Roehrs, T., Shambroom, J. and Roth, T. (2013) Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Journal of Clinical Sleep, 9(11), 1195-1200.
  • Harvard Medical School (2014) Blue light has a dark side. Harvard Health Publications. Accessed on: 08/04/2020 at
  • Jaehne, A., Unbehaun, T., Feige, B., Lutz, U. C., Batra, A. and Riemann, D. (2012) How smoking affects sleep: A polysomnographical analysis. Sleep Medicine, 12(10), 1286-1292.
  • Sleep Health Foundation (2017) Good sleep habits. Sleep Health Foundation website. Accessed on: 08/04/2020 at
  • Suen, L. K. P., Tam, W. W. S. and Hon, K. L. (2010) Association of sleep hygiene-related factors and sleep quality among university students in Hong Kong. Hong Kong Medical Journal, 16, 180-185.
  • Orzel-Gryglewska, J. (2010) Consequences of Sleep Deprivation. International Journal of Occupational Medicine and Environmental Health, 22(1), 95-114.

InterDynamics News


InterDynamics’ staff continue to operate from home at this time. Training is still available via Internet video conferencing.

In the News

Provided below are a selection of articles from around the web on the issues associated with fatigue. We hope you find them useful and interesting.

Video: Why Sleep Matters Now More Than Ever

Matt Walker, Ted Connects, April 2020
A good night’s sleep has perhaps never been more important. Sharing wisdom and debunking myths, sleep scientist Matt Walker discusses the impact of sleep on mind and body – from unleashing your creative powers to boosting your memory and immune health – and details practices you can start (and stop) doing tonight to get some rest.

Article: Stressed to the Max? Deep Sleep Can Rewire the Anxious Brain

Yasmin Anwar, Science Daily, November 2019
When it comes to managing anxiety disorders, William Shakespeare’s MacBeth had it right when he referred to sleep as the “balm for hurt minds.” While a full night of slumber stabilizes emotions, a sleepless night can trigger up to a 30% rise in anxiety levels, according to new research from the University of California, Berkeley.

Article: Why Reading Before Bed Could Improve Your Sleep

Georgia James, Huffington Post, September 2016
With our technology driven 24/7 lifestyles, it’s little wonder so many of us go to bed with our minds still whirring from the stresses of the day. If, like many, you find it difficult to unwind and switch off at bedtime, a good book could be your best ally.

Issue #62 – November/December 2019

Welcome to Focus on Fatigue!

As the year comes to an end, the staff of InterDynamics would like to wish you and your family a joyful festive season and a safe, well-rested start to the new year.

The FRMS Team



InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 7 3229 8300

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).

Featured Articles

Working Nights: Getting Enough Sleep

Getting enough sleep is one of the greatest challenges faced by night shift workers. The human body is designed, through the circadian rhythm, to sleep during the night and be awake during the day. Flipping this rhythm on its head comes with all sorts of negative consequences. However, in a recent article, researchers McKenna and Wilkes (2018) provided some guidelines shift workers can follow in order to maximise the amount of sleep they achieve while working night shifts.

Minimise sleep debt before night shifts

Shift workers should aim to get plenty of sleep before their night shifts begin, to ensure they aren’t going in already burdened by a sleep debt. This could include sleeping in on the morning before the first night shift and taking an afternoon nap before work begins.

Improving performance while on shift

Performance at work can be temporarily improved in a number of ways. A short nap (less than 30 minutes) improves alertness without inducing sleep inertia (the groggy feeling upon waking). The consumption of caffeine has been shown to improve several aspects of cognitive performance such as attention and reasoning. Exposure to bright light during night shifts can reduce sleepiness, but possibly comes with its own negative consequences. Risk can also be reduced by adding extra checks during critical tasks, especially in the early hours of the morning.

Meal timing

So far, research evidence suggests that it’s best to eat a main meal before starting a night shift. Limiting food consumption during shifts to small, healthy snacks can help stave off hunger and increase comfort levels.

Sleep between shifts

Employing sleep hygiene principles to eliminate factors that disrupt sleep can help keep sleep debt to a minimum between shifts. These include avoiding bright daylight during the commute home, creating a cool, dark, quiet sleep environment, wearing an eye mask, and maintaining a regular bedtime routine. Caffeine should be avoided in the six hours leading up to sleep.

Resetting the system

It’s important to get back to sleeping during the night after night shifts are finished. Further research on the best way to do this is still required. However, one approach suggests napping for one or two full sleep cycles after the last night shift is finished (90 minutes or 180 minutes) and then getting some bright daylight before returning to a normal sleep rhythm.

Other thoughts

It has also been suggested that chronotype and social jetlag should be taken into account when discussing the challenges posed by night shift work. Chronotype refers to an individual’s natural sleeping pattern (e.g. early birds versus night owls). Social jetlag refers to the disruption caused to the circadian rhythm by societal commitments (e.g. getting up early on weekdays but sleeping in on weekends). One study used chronotype to match workers to shift times and found this significantly reduced social jetlag and improved sleep duration between shifts.


  • McKenna, H. and Wilkes, M. (2018) Optimising sleep for night shifts. BMJ, 360:j5637, doi: 10.1136/bmj.j5637.
  • Uzoigwe, C. E. (2018) Night shifts: Chronotype and social jetlag. BMJ, 360:j5637, doi: 10.1136/bmj.j5637.


InterDynamics News

Conferences and presentations

11th International Conference on Managing Fatigue

The ‘Managing Fatigue’ conference series is now an established and respected forum for research updates and discussion in the fatigue management community. First convened in 1992 by Professor Laurence Hartley, each conference has primarily focused on the effects of fatigue in the transportation sector . Over the years the meeting focus has also evolved to encompass a wider arena including sectors such as Aviation, Maritime, Industrial, Resources and Health.

When: 16-19 March 2020
Where: Fremantle, Western Australia

Not only will InterDynamics be presenting at the Conference, but we’re also sponsoring a coffee cart! Be sure to grab a cup of coffee and come for a chat with us at the conference.

More details can be found here.

In the News

Provided below are a selection of articles from around the web on the issues associated with fatigue. We hope you find them useful and interesting.

Video: Fatigue rules finalised 2019
CASABriefing, YouTube, 15 September 2019
‘Fatigue rules finalised’ explains how the 2019 fatigue rules have been developed drawing on contemporary scientific data, and features interviews with internationally renowned fatigue specialists. It discusses the importance of implementing systems and processes to support safety critical roles – how building strategic fatigue risk mitigations reduce the probability of an individual becoming fatigued to a degree that impairs their performance and results in an increased risk to flight safety.

Article: Australians cite lack of sleep as leading barrier to a healthy life
Melissa Cunningham, Sydney Morning Herald, 29 September 2019
Researchers examined the effects that social determinants such unstable housing, poverty and isolation have on overall health outcomes, finding more than a third of Australian respondents (35 per cent) cited sleep deprivation as their top concern, followed closely by mental health worries (26 per cent).

Issue #61 – September/October 2019

Welcome to Focus on Fatigue!

These days, we’re all familiar with the three pillars of health: nutrition, exercise and sleep. Each one comes with its own set of rules that seem to get more complex with every internet article we read. That’s before we even start to look at all the ways our three pillars interact! It’s not a wonder we sometimes feel overwhelmed by all the available, and sometimes contradictory, information.

In this month’s Focus on Fatigue, we’ll attempt to untangle one aspect of the interaction between exercise and sleep. Can you exercise at night and still get a good night’s sleep? The findings may just help you rest easy.

Best wishes,
The FRMS Team


InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 7 3229 8300

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).

Featured Articles

Exercise and Sleep: Can One Follow the Other?

Exercise. It’s like a little shot of goodness for your mind and body. Studies have found that regular doses of exercise will help you feel better on the inside and look better on the outside. You’ll be happier, more relaxed, less likely to get sick, have more energy during the day, and even have a better memory. Exercise will also help you sleep better. In fact, exercise can help you go to sleep faster, stay asleep longer, and wake up less often during the night.

So, what the problem?

At some point in the past, people began to wonder if exercising at night was such a good idea. Would evening exercise interfere with getting a good night’s sleep? There seemed to be three main hypotheses around this idea:

  1. Exercise increases core body temperature and stimulates the nervous system, which could make it more difficult to fall asleep;
  2. Exercise could lead to a stress response in people with low fitness levels, which could interfere with sleep; and/or
  3. Muscle soreness resulting from exercise could make it hard to sleep.

Are any of these hypotheses true?

All of these hypotheses have been tested over time. At first, researchers looked mainly at how much time elapsed between when participants worked out and when they went to bed. However, more recent studies have included variables such as exercise intensity and duration. While the findings have sometimes been contradictory, a recent meta-analysis of the research found that exercise in the evening does not seem to negatively affect sleep. In fact, there is the potential that evening exercise improves sleep, however the effects were small and possibly due to normal variations in sleep patterns.

One possible exception

There could possibly be some interaction effects between variables such as exercise intensity and duration that do have some impact on sleep. For example, some studies have found that sleep may be slightly impaired if the exercise is vigorous, and performed within an hour of bedtime. This may be due to an increase in heart rate, which takes time to calm down. The data here is far from conclusive, but it’s something to watch out for.

The conclusion

Sleep is important, but so is exercise. If you enjoy exercising before bedtime, or if it’s the most convenient time to squeeze in a workout, don’t hold off due to concerns that it will interfere with your ability to get a good night’s sleep. You can go for that long evening jog, and catch your ZZZs too.


  • Banno, M., Harada, Y., Taniguchi, M., Tobita, R., Tsujimoto, H., Tsujimoto, Y., Kataoka, Y. and Noda, A. (2018) Exercise can improve sleep quality: A systematic review and meta-analysis. PeerJ, 6:e5172; DOI 10.7717/peerj.5172.
  • Myllymaki, T., Kyrolainen, H., Savolainen, K., Hokka, L., Jakonen, R., Juuti, T, Martinmaki, K., Kaartinen, J., Kinnunen, M.-L. and Rusko, H. (2011) Effects of vigorous late-night exercise on sleep quality and cardiac autonomic activity. Journal of Sleep Research, 20, 146-153.
  • Stutz, J., Eiholzer, R. and Spengler, C. M. (2019) Effects of evening exercise on sleep in healthy participants: A systematic review and meta-analysis. Sports Medicine, 49, 269-287.

In the News

Provided below are a selection of articles from around the web on the issues associated with fatigue. We hope you find them useful and interesting.

Video: Can Exercise Improve Your Sleep?
PictureFit, YouTube, 30 September 2016
Want to Improve Your Sleep? Perhaps fall asleep quicker? How about just sleep longer? Find out how exercise can improve your sleep gainz!

Article: Physical Activity in the Evening Does Not Cause Sleep Problems
ETH Zurich, Science Daily, 18 December 2018
Even among sleep researchers, it is a widely held belief that sleep quality can be improved by avoiding exercise in the evening. However, as researchers from the Institute of Human Movement Sciences and Sport at ETH Zurich have demonstrated, it is not generally true.

Issue #60 – July/August 2019

Welcome to Focus on Fatigue!

Winter is now well underway here in Australia. That means the sun is slow to wake up in the morning and it goes to bed much earlier. For shift workers, the idea of having such a regular routine of waking and sleeping is far from the norm. Working non-standard hours, and trying to get adequate sleep during off-times, comes with huge challenges which can, at times, seem overwhelming.

In this month’s Focus on Fatigue we’ll be talking about Shift Work Disorder. What is it? And what can shift workers do to reduce its symptoms?

Best wishes for the month ahead,
The FRMS Team


InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 7 3229 8300

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).

Featured Articles

Shift Work Disorder

Most people who work shifts will struggle, at times, with periods of insomnia or excessive sleepiness. Such struggles can be said to be a ‘normal’ reaction to staying awake when your body wants to sleep and trying to sleep when your body wants to be awake. However, for some shift workers, the demands of shift work result in ongoing sleep challenges that begin to interfere with both work and family life. This is where the term ‘Shift Work Disorder’ begins to apply.

What is Shift Work Disorder?

Shift Work Disorder (SWD) is a Circadian Rhythm Sleep Disorder. The National Sleep Foundation lists the symptoms of SWD as follows:

  • Excessive sleepiness when you need to be awake, alert, and productive.
  • Insomnia, or the inability to sleep when you need to. This can mean trouble falling asleep, or waking up before you’ve slept sufficiently.
  • Sleep that feels unrefreshing or insufficient.
  • Difficulty concentrating.
  • Lack of energy.
  • Irritability or depression.
  • Difficulty with personal relationships.

It is estimated that around 10% of all shift workers suffer from SWD. The disorder can develop in those who work night shifts, rotating shifts, or early morning shifts. The symptoms inherent in SWD can result in sufferers experiencing a state of chronic sleep deprivation, which has significant implications for health, productivity and safety.

Coping with Shift Work Disorder

It is important that sufferers of SWD make sleep a priority in order to reduce the impact of symptoms. For example:

  • Maintain a sleep diary – this may help identify problem patterns that can be adjusted and give an indication of how much sleep you’re achieving in each 24-hour period.
  • Regulating light exposure – minimise exposure to light on the way home from night shift, but get lots of bright light before the start of shifts to suppress melatonin.
  • Bedtime rituals – following regular bedtime rituals, such as putting on pyjamas and brushing teeth, can be a subtle way of telling the brain it is time for sleep.
  • Maintain good sleep hygiene – even if you are sleeping during the day, it is important that your bedroom is cool, quiet and dark.
  • Do Not Disturb – put a sign on the front door to prevent disturbances.
  • Work hours – If possible, decrease the number of night shifts in a row to a more tolerable level.
  • Napping – If possible, plan a nap before or during your shift. This will help to improve alertness.

When Behavioural Interventions are Not Enough

For times when the symptoms of SWD persist, despite good behavioural practices, there are a number of pharmacological interventions that can be used to increase wakefulness at work and assist with sleeping at home. However, these substances often come with side effects and other concerns (such as issues with tolerance). It is important to discuss the pros and cons of such interventions with your doctor.


  • Australasian Sleep Association (2019) Shift work sleep disorder. Accessed: 05/06/19.
  • National Sleep Foundation (2019) Shift work disorder symptoms. Accessed: 05/06/19.
  • Cleveland Clinic (2019) Shift work sleep disorder: Management and treatment. Accessed: 05/06/19.


In the News

Provided below are a selection of articles from around the web on the issues associated with fatigue. We hope you find them useful and interesting.

Video: Matt Walker: Sleep is Your Superpower
Matt Walker, TED Talks, April 2019
Sleep is your life-support system and Mother Nature’s best effort yet at immortality, says sleep scientist Matt Walker. In this deep dive into the science of slumber, Walker shares the wonderfully good things that happen when you get sleep — and the alarmingly bad things that happen when you don’t, for both your brain and body. Learn more about sleep’s impact on your learning, memory, immune system and even your genetic code — as well as some helpful tips for getting some shut-eye.

Article: Neurologist Exposes Dangers Of Sleep-Tracking Apps
Jan Cortes, Medical Daily, 10 June 2019
If you’ve had trouble sleeping at some point in your life, then you are probably one of the many people who have turned to sleep-tracking applications in hopes of getting “enough sleep.” And at the best of times, this might have worked for you. But does the use of these apps have any negative effects?

Welcome to Focus on Fatigue!

There are a lot of things we struggle to remember. People’s names, the title of that book someone recommended, where we put our car keys. Then there are all those events we’d like to forget, like that embarrassing thing we did in high school (we ALL have at least a few of those memories). Thankfully, for most of us, the not-so-great memories are far outweighed by the many happy moments that are scattered throughout a life. Wedding days, the births of children, the time we performed perfectly at a piano recital or recalled every fact needed to get an A on an important exam.

In this month’s Focus on Fatigue, we’ll be looking at the different types of memory, how memories are formed, and how to ensure the memories we want to hold onto last a lifetime. Unsurprisingly, it’s all a matter of a good night’s sleep.

Best wishes,
The FRMS Team


InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 7 3229 8300

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).

Featured Articles

Sleeping to Remember

In the past, sleep has often been viewed as wasted time. But as more and more research is done on sleep, we’ve begun to realise just how active our brains are during those hours of slumber. Just because we’re not conscious of what our brain is doing during sleep, doesn’t mean there is nothing going on. One of the many ways in which our brain is helping us while we sleep is in the consolidation and regulation of memories.

There are different types of memory, including short-term memory (remembering a new phone number long enough to write it down) and long-term memory. Within long-term memory are explicit memory (conscious) and implicit memory (unconscious). Explicit memory can then be broken down into episodic memory (memories of events that have happened to you) and semantic memory (your general knowledge about the world). Finally, implicit memory can be broken down in priming (the word ‘bread’ is likely to make you think of the word ‘butter’ but not the word ‘doctor’) and procedural memory (learned motor skills such as how to drive a car). That’s a lot of different types of memory for the brain to keep track of!

How do memories form?

When you drift off to sleep at night the neurons in your hippocampus come alive, performing a replay of the memories from that day. The hippocampus and the neocortex spend time sifting through these memories, deciding what needs to be stored and what can be forgotten. Important memories are then stored in the neocortex so they can be recalled in the future. This replay only happens during sleep. Which means, if you don’t get enough sleep, those memory you’re making won’t be consolidated and you’re less likely to retain them.


When you recall a memory (either consciously or unconsciously) you are reactivating the neurons where that memory is stored. These neurons are connected through synapses, which can be strengthened or weakened depending on how often you recall the memory (the ability of the brain to make these ongoing changes is called synaptic plasticity). This is why you can remember events from long ago, such as the birth of a child or the first time you were stung by a bee. Because the memories are important to you, or caused a strong emotional reaction. By remembering them many times, you’ve created strong connections between the neurons where the memories are stored.


What did you have for breakfast on the second Tuesday of last month? You probably knew the answer to that question the next day, maybe even the day after. But as time passed you’ve probably forgotten. What happened to those memories?

This is another way in which sleep helps us to regulate memories. Not only does it help us retain important memories, but it helps us forget memories that aren’t important. This is done through a process called ‘synaptic homeostasis’ (it’s still a hypothesis currently, but the evidence is mounting). The theory suggests that during sleep there is an overall weakening of the synaptic connections throughout the brain. Memories that had weak connections in the first place will be forgotten, while those with strong connections will continue to be retained. This effectively ‘cleans the slate’ so that we’re able to learn new information and make new memories upon waking.

Sleep stages and memory type

Studies have found evidence that different stages of sleep are important for different types of memory. For example, REM (Rapid Eye Movement) sleep is thought to be important for emotional memories (the painful sting of that bee) and for procedural memories (driving a car, playing the piano). Meanwhile, slow-wave sleep (deep, restorative sleep) is important for episodic memories. Motor learning has also been linked to the lighter stages of sleep.

The research is still in its early stages here, but the implication is clear: if you want good consolidation of all memory types, you need to be cycling through all the various stages of sleep.

Learning new information

The learning of new information is often described as having three parts: the acquisition of new information, the consolidation of this information through memory formation (occurs during sleep) and recall of the information. While we’ve already discussed how a lack of sleep effects the consolidation of new information, there are a number of other ways in which sleep deprivation interferes with learning. For example:

  • Lack of focus, attention and vigilance
  • Over-worked neurons no longer able to coordinate information properly
  • Reduced ability to access previously learned information
  • Judgement becomes impaired
  • Negatively impacts mood, making learning more difficult

While we may not have all the answers on how sleep and memory work, the evidence is clear. If you want to lay down good memories, clear out unimportant memories, and have access to the information you’ve taken the time to learn – get a good night’s sleep.


  • Blanco, W., Pereira, C. M., Cota, V. R., Souza, A. C., Rennó-Costa, C. and Santos, S. (2015) Synaptic Homeostasis and Restructuring across the Sleep- Wake Cycle. PLoS Computational Biology, 11(5): e1004241.
  • Kirszenblat, L. (2017, October 19) Sleep deprivation: Why your brain needs to go to sleep. Queensland Brain Institute. Retrieved from
  • Harvard Medical School (2007) Sleep, learning, and memory. Retrieved from
  • Squire, L. R., Genzel, L., Wixted, J. T. and Morris, R. G. (2019) Memory consolidation. Cold Spring Habor Perspectives in Biology, 7, a021766.

InterDynamics News

FAID Quantum Utilised in Research on U.S. Police Rosters

A research team at Washington State University recently published a paper in which FAID Quantum was used in an investigation of the association between police fatigue and complaints made by members of the public. The details are given below:

Riedy, S. M., Dawson, D., and Vila, B. (2019) U.S. police rosters: Fatigue and public complaints. Sleep, 42(3), 1-10.


Study Objectives: Recent experimental research indicates a substantial impact of shift work related fatigue on police officers’ encounters with the public. In recent years, biomathematical models of fatigue have provided a new way to identify potential relationships between working time arrangements and job performance. This study focused on public complaints against police officers and determined whether the odds of a public complaint were associated with work schedules and/or a biomathematical model’s predictions of fatigue and sleepiness.

Methods: N = 144 police officers from two municipal police departments in the United States reported shift start times, shift hours, court hours, and public complaints each duty day during study participation. A biomathematical model of fatigue (FAID Quantum) predicted sleep duration and sleep timing and inferred fatigue and sleepiness for 15 744 shifts. Fatigue, sleepiness, 24 hr sleep estimates, and work schedule were tested as predictors of public complaints.

Results: Greater fatigue, greater sleepiness, and less sleep in the 24 hr prior to a shift increased the odds of a public complaint (F ≥ 9.14, p < 0.01). Working back-to-back night shifts increased the odds of a public complaint (OR = 4.27, p < 0.01), particularly when off-duty court hours were worked between the night shifts (OR = 4.73, p < 0.01).

Conclusions: On-duty fatigue and sleepiness, sleep obtained prior to a shift, and working night shifts were strongly associated with public complaints. Off-duty court appearances reduced sleep between night shifts and further increased the odds of a public complaint. The results suggest that off-duty court hours should be limited between night shifts and duty schedules should be considered when scheduling court appearances.

In the News

Provided below are a selection of articles from around the web on the issues associated with fatigue. We hope you find them useful and interesting.

Video: The benefits of a good night’s sleep
Shai Marcu, TED-Ed (5 January 2015)
It’s 4am, and the big test is in 8 hours. You’ve been studying for days, but you still don’t feel ready. Should you drink another cup of coffee and spend the next few hours cramming? Or should you go to sleep? Shai Marcu defends the latter option, showing how sleep restructures your brain in a way that’s crucial for how our memory works.

Article: Memory ‘brainwaves’ look the same in sleep and wakefulness
University of Birmingham (9 October 2018)
Identical brain mechanisms are responsible for triggering memory in both sleep and wakefulness, new research at the University of Birmingham has shown. The study sheds new light on the processes used by the brain to ‘reactivate’ memories during sleep, consolidating them so they can be retrieved later.

Welcome to Focus on Fatigue!

The past couple of months seem to have been a study of extremes. Extreme cold in some parts of the world, and extreme heat in others. As someone who is firmly located in the heat, I know firsthand that such extremes can have a significant effect on how well we sleep at night.

So, whatever part of the world you’re in, I hope you’re managing to get a good night’s sleep, whether that’s bundled up in blankets or cover-free with the ceiling fan on high.

Best wishes,
The FRMS Team



InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 7 3229 8300

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).

Featured Articles

Working with Risk

When we talk about Fatigue Risk Management, we are talking about managing increases in the risk of accident and injury associated with increases in fatigue. It’s all about keeping people safe. One part of managing such risk is knowing when accidents at work are mostly likely to occur.

A number of studies have examined this issue in detail and the following trends have been identified.

Risk across different shifts

There is a consistent tendency for the relative risk of accidents to be lowest for morning shifts, increased for afternoon shifts, and highest for night shifts (on 8-hour shift systems). Across a number of studies, the relative risk for incidents was 30% higher on the night shift than on the morning shift.

Risk over successive night shifts

In a group of studies that examined the risk of accident over the course of four consecutive night shifts, it was found that risk increased substantially for each night. Indeed, the risk of having an accident on the fourth night was 36% higher than it was on the first night. This same increase was found in the day shift, but to a much milder degree.

Risk over successive hours of work

Risk of accident tends to increase exponentially after the 8th hour on shift. Relative to this first 8-hour period, 10-hour shifts are associated with a 13% increase in risk. The increase in risk for a 12-hour shift is 27%.

Risk between shift breaks

The risk of having an accident rises in the time between breaks, with accidents most likely to happen in the 30 minutes prior to a rest break.

What about the Circadian Rhythm?

The circadian rhythm is an internal body clock that cycles between periods of sleepiness and alertness throughout the day and night. It’s one of the reasons we get sleepy after the sun goes down, but it’s also responsible for that post-lunch slump that makes us want to take a nap. For most adults, the biggest dips in energy occur between about 2am and 4am, then again between 1pm and 3pm. Therefore, it seems natural that there would be an increase in risk of injury for shift workers who are working during the circadian dip in the early hours of the morning.

While this is far from proven, there is some evidence to support the theory. For example, a study of truck drivers found a major peak in accidents occurring around 3am. This increase was not necessarily due to drivers falling asleep at the wheel, but seemed to be due more to a decrease in driving performance. So, if you are working during this time of the morning, it may be useful to schedule a break if possible.


  • Folkard, S. and Tucker, P. (2003) Shift work, safety and productivity. Occupational Medicine, 53, 95-101.
  • Folkard, S. (1997) Black times: Temporal determinants of transport safety. Accident Analysis and Prevention, 29(4), 417-430.
  • Folkard, S., Lombardi, D. A. and Tucker, P. T. (2005) Shift work: Safety, sleepiness and sleep. Industrial Health, 45, 2-23.

In the News

Provided below are a selection of articles from around the web on the issues associated with fatigue. We hope you find them useful and interesting.

Article: 8 weird facts about sleep science learned in 2019 alone
JR Thorpe, Bustle (6 February 2019)
Maybe it’s because 2018 was a hell of a year and we all want to spend most of 2019 in sweet, sweet slumber, but there was a lot of research published in January this year about sleep. Like, a lot of research. This article checks out what we’ve learned so far.

Article: The connection between sleep and pain
Lydia Denworth, Psychology Today (5 February 2019)
A new study reveals how sleep loss changes brain processing to increase pain.

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