Focus on Fatigue

Issue #77 – May 23

Welcome to Focus on Fatigue!

We are often asked for advice on how to assess whether fatigue contributed to an incident and if it can be determined simply by looking at the FAID Score at the time of the incident? The short answer is no. A systematic and situation-specific assessment is required to determine whether fatigue was a contributing factor to an accident or incident.

In this issue of Focus on Fatigue, we will provide some insight into this process.

We trust you find it useful 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).

Assessing Fatigue as a Contributing Factor to an Incident

Fatigue is a serious and complex issue and many organisations struggle with how to assess and determine whether fatigue contributed to an incident or accident. So, let’s have a look at this process. We will provide an overview of the information needed for a thorough investigation and identify personal and corporate/systemic fatigue-related contributors. We will also introduce the GRAID Investigation Tool, which can assist organisations in this assessment process.

Specific Details of the Occurrence

To assess whether fatigue was a contributing factor to an incident, you need to collect specific details of the occurrence. This includes timing, personnel involved, context, and incident details. This information will help you understand the circumstances surrounding the incident and determine whether fatigue may have played a role.

Preliminary Details

Once you have collected the specific details of the occurrence, you need to consider preliminary details related to the individuals involved and the circumstances surrounding the incident. This involves assessing factors such as:

  • FAID Quantum hours of work assessment
  • workload impacts
  • work environment impacts
  • non-compliance to work/rest rules
  • self assessed Karolinska Sleepiness Scale
  • self observed symptoms/behaviours
  • personal health/medication
  • third-party observations of symptoms/behaviours.

Assessing these questions will give you an initial determination as to the likelihood that fatigue was a significant contributing factor. If the likelihood is low, then no further investigation may be necessary. However, if the likelihood is not determined to be low, further investigation is warranted.

Personal and Corporate/Systemic Fatigue-Related Contributors

The next stage of the investigation involves assessing both personal and corporate/systemic fatigue-related contributors. Factors to consider include:

  • the use of rest days
  • secondary employment
  • jetlag/significant recent time zone changes
  • prior sleep in the previous 48 hours
  • fatigue-related training
  • sleep disturbance due to alcohol
  • commute time prior to the occurrence
  • sleep inertia
  • fatigue detection technology
  • quality of employer-provided sleeping environment
  • predictability of working hours
  • medical screening and monitoring
  • record of absenteeism/sick days
  • expectations and incentives that may increase personal fatigue
  • whether rostering practices take into account fatigue
  • alerting strategies and control measures

GRAID Investigation Tool

The GRAID Investigation Tool by InterDynamics was developed, together with Integrated Safety Support, to assist organisations in this assessment process. The tool applies a risk grading system developed by Zurich Risk Engineering and offers a consistent and practical approach to reviewing incidents, accidents, occurrences, and fatigue reports.

Likelihood that fatigue contributed to incident

GRAID IT systematically steps the user through a review of 28 weighted fatigue-related elements. Once the investigation is complete, GRAID IT provides a grading of the likelihood that fatigue contributed to the occurrence, and the related scorecard can be reviewed. By taking a systematic approach to assessing fatigue, organisations can identify contributing factors and take steps to prevent future incidents.

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.

Reducing fatigue and errors among nurses working night shifts

McGill University, April 2023

Nurses exposed to 40 minutes of bright light before their night shifts feel less fatigued and make fewer errors at work, according to a study led by McGill University. The nurses also slept better after their shifts.


Driving on less than 5 hours of sleep is just as dangerous as drunk-driving, study finds

Madeline Sprajcer & Drew Dawson, The Conversation, April 2023

A new study has found that if you had less than five hours of sleep last night you are just as likely to have a vehicle crash as if you were over the legal limit of alcohol.


RTD says light rail operator “likely fell asleep” before W-Line train derailed at Golden station

Jon Murray, The Denver Post, April 2023

Transit agency’s corrective plan proposes evaluating shift durations and fatigue-awareness campaign.

Issue #76 – March 23

Welcome to Focus on Fatigue!

Sleep is not always the easiest thing to come by, especially for those working long or night shifts. When we are deprived of adequate sleep, many of us are faced with a number of important questions. How tired am I? Can I continue working? Is my work performance suffering? Am I putting myself or others at increased risk? We all like to think we can accurately identify our level of fatigue and how we’re being affected by it, but is this actually the case? Do we know how tired we really are? Is fatigue self-monitoring an effective fatigue risk management strategy? This is the question we’ll be investigating in this month’s Focus on Fatigue.

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).

How Accurate is Fatigue Self-Monitoring?

Do we know how tired we really are?

Many shift workers rely on self-monitoring to assess their fatigue levels. But the question arises, how good are individuals at assessing their own level of fatigue and whether fatigue is impacting their performance?

Tired at work - person yawning

Self-monitoring of fatigue levels: moderately good but not perfect

Studies have found that people are fairly good at recognizing when sleep deprivation is affecting their performance on simple tasks. However, one study of Australian fire fighters found that this ability to self-monitor performance begins to deteriorate after prolonged periods of wakefulness. Moreover, people tend to either over or under-estimate the degree that fatigue is hampering their performance. The ability to self-monitor fatigue can also be reduced during a person’s biological night (when our circadian rhythm is telling us we should be asleep).

Post-work evaluations are more accurate than predictions

Generally, people are better at evaluating their performance after completing a task, than predicting their performance before starting it. However, when it comes to risk management, pre-performance assessments are more valuable in reducing the risk of accidents or injuries. Feedback during the completion of a task can also lead to more accurate evaluation of performance.

Global predictions are more accurate

People tend to be better at making global predictions about our performance than they are at predicting how well they’ll do on particular tasks. For example, one study found that after a week of simulated night-shifts, participants were better able to predict their performance overall, than they were able to predict their performance for specific shifts.

This means that we aren’t necessarily great at identifying which tasks will be affected by our levels of fatigue. Considering that sleep deprivation does not affect all types of activities equally, such global predictions mean that we may not be good at adjusting our prediction of how well we will perform based on the type of activity we will be performing.

Acknowledging fatigue won’t help improve our performance – much

There can be a tendency to think that if we acknowledge how fatigued we are, then we can improve our performance by ‘trying harder.’ To a certain degree this is true. Studies have found that motivation to do well can make a difference to performance in people who are sleep-deprived (this depends heavily on the severity of the deprivation). However, it is important to remember that the best way to deal with fatigue, especially when we are able to recognize that fatigue is affecting our work performance, is to stop working and take a break or, preferably, have a sleep.

Work culture is also important

Fatigue will most commonly be apparent to a worker long before they cease to be ‘capable’ of working. Therefore, a person who acknowledges they are experiencing a high level of fatigue is not necessarily saying ‘I can’t continue working’ but may actually be saying ‘I believe it may be unsafe for me to continue working.’ It is imperative that workplace culture supports individuals who recognize that fatigue is impeding their work performance and wish to take steps to rectify the situation.

One useful tool

Overall, research tells us that self-monitoring can be one useful tool to assist in determining fatigue risk in the event of sleep deprivation. However, because our own assessment of fatigue has its limitations and is not necessarily as accurate as we would like to think it is, we should also be using the other tools at our disposal to assess risks that might be present as a result of fatigue.


  • Armstrong, T. A., Cvirn, M., Ferguson, S. A., Christoforou, T. and Smith, B. (2013) Can Australian bush fire fighters accurately self-monitor their cognitive performance during a 3-day simulated fire-ground campaign? Sleep, performance and well-being in adults and adolescents, 18-23. 10th Annual Meeting, Australiasian Chronobiology Society: Adelaide.
  • Baranksi, J. V., Pigeau, R. A., and Angus, R. G. (1994) On the ability to self-monitor cognitive performance during sleep deprivation: A calibration study. Journal of Sleep Research, 3(1), 36-44.
  • Dorrian, J., Lamond, N., Holmes, A. L., Burgess, H. J., Roach, G. D., Fletcher, A., and Dawson, D. (2003) The ability to self-monitor performance during a week of simulated night shifts. Sleep, 26(7), 871-877.
  • Muldoon, N., Sargent, C., Zhou, X., Kosmadopoulos, A., Darwent, D. and Roach, G. D. (2013) The efficacy of subjective ratings is limited during the biological night. Sleep, performance and well-being in adults and adolescents, 7-12. 10th Annual Meeting, Australiasian Chronobiology Society: Adelaide.
  • Dorrian, J., Lamond, N. and Dawson, D. (2000) The ability to self-monitor performance when fatigued. Journal of Sleep Research, 9, 137-144.

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.

Drowsy driving - blurry road at night

Drowsy drivers just won’t stop soon enough, AAA study finds

Gary Gastelu, Fox News, March 2023

A new study found that not enough drivers are taking a hint from their bodies and continuing for too long on their journeys when they should be stopping to rest. About 75% of tired drivers kept going despite the risks.


Human brain looks years ‘older’ after just one night without sleep, small study shows

Rebecca Sohn, Live Science, February 2023

A study suggests that just one night of sleep deprivation may be linked to structural changes in the brain, similar to those seen in aging.


Ignoring fatigue a slippery slope for health and safety on the farm

Erin Kelly, Wellington Advertiser, March 2023

We often hear farmers say, “I’ll sleep when the busy season is over.” But that overlook, even if intended jokingly, is a slippery slope for health and safety considerations.

Issue #75 – August 2022 – Why We Sleep

Welcome to Focus on Fatigue!

Sleep! It’s the activity we spend up to a third of our life doing (or attempting to!). So, it’s no wonder there is continually new research seeking to better understand how and why we sleep and what happens when we don’t.

In this issue of Focus on Fatigue, we bring you some recent studies on sleep and feature a review of Matthew Walker’s book ‘Why We Sleep?’.

We hope you find it interesting 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).

Why We Sleep?

Book Review – Why We Sleep by Matthew Walker

As founder-director of the Center for Human Sleep Science at the University of California, Berkeley, Matthew Walker has brought together into one book many recent studies in sleep research. He has analysed everything from sleep’s role in Alzheimer’s disease and depression, to its influence on learning and productivity.

An example of a fascinating study is the comparison between two similar businesses in towns on the east and west of the same time zone. The differences in productivity for individuals across this time zone were remarkable. In fact, those in the east, who get up when it is lighter and finish work when the sun goes down, not only slept better and were more productive but they even received more frequent increases in salary.

Walker’s 12 tips for healthy sleep are:

  1. Stick to a sleep schedule. Go to bed and wake up at the same time each day. You can’t make up for lost sleep. This is the most important sleep habit.
  2. Exercise at least 30 minutes on most days, but not later than three hours before bedtime.
  3. Avoid caffeine and nicotine in the late afternoon. These take time to wear off.
  4. Avoid alcoholic drinks before bed. Alcohol robs you of REM sleep, keeping you in the lighter stages of sleep.
  5. Avoid large meals and beverages late at night.
  6. Avoid medicines that disrupt sleep. Talk to your GP about whether medication contributes to insomnia, and ask about the best time to take medication so as not to affect sleep.
  7. Don’t take naps after 3pm.
  8. Relax before bed.
  9. Take a hot bath or shower before bed.
  10. Dark bedroom, cool bedroom, gadget free bedroom.
  11. Have the right sunlight exposure. Daylight is key to sleep.
  12. Don’t lie in bed awake. Get up and do something relaxing if you are lying awake worrying about not sleeping. Go back to bed when you start to feel sleepy.

The book is available in print, ebook or audiobook format, and explains the science behind the various studies in everyday language.

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.

How Living on the Wrong Side of a Time Zone Can Be Hazardous to Your Health

Christopher Ingraham, Washington Post, April 2019

It turns out that living on the wrong side of a time zone’s boundary can have negative consequences on a person’s health and wallet.


Scientists Find 7 Hours’ Sleep is Best for Middle-Aged Brains

Lisa Rapaport, Everyday Health, May 2022

Middle-aged and older adults have worse cognitive function when they get too little or too much sleep, a new study suggests.


Children Who Lack Sleep May Experience Detrimental Impact on Brain and Cognitive Development That Persists Over Time

University of Maryland School of Medicine, Science Daily, July 2022

Elementary school-age children who get less than nine hours of sleep per night have significant differences in certain brain regions responsible for memory, intelligence and well-being compared to those who get the recommended nine to 12 hours of sleep per night, according to a new study.


Study of AFL Players Reveals the Importance of Good Sleep

7NEWS Australia, Jan 2022

Australian Football League stars are teaming up with Melbourne researchers to expose the dangers of poor sleep. A study of dozens of players has found a clear link between a lack of rest and mental health issues.


Theory for Why Sleep Enhances Learning Confirmed by New Study

Technology Networks, April 2022

The consolidation of learning that occurs during sleep is a result of the learning process and not merely because certain brain regions get used a lot during learning.


Researchers Find What Magpies Lose from Hitting Snooze

Stuart Layt, Brisbane Times, May 2022

Australian magpies are known for their beautiful morning calls, but new research has confirmed that just like some humans, if they don’t get a good night’s sleep they will put off their morning plans to have a sleep-in.

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.

Issue #73- March 2022

Welcome to Focus on Fatigue!

It’s been a busy few months here at InterDynamics and we are excited to share with you what we’ve been up to.

Our feature article also looks at two recent studies that offer hope for the long term health of shift workers.

We trust you find this issue interesting 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).

InterDynamic News

FAID Quantum Web Service

We are excited to let you know that we have been working hard behind the scenes creating FAID Quantum Web Service. This web based version of FAID Quantum will offer convenience and accessibility along with a modernized user interface. FAID Quantum Web Service will allow us to service an even broader market; expanding our range of options to suit your requirements. FAID Quantum Web Service is still in the early stages of release but is available for trial by visiting and signing up for a free trial account. We welcome your feedback!

Covid Resilient Rostering

We have assisted a number of companies with bespoke Roster Design Solutions, taking into account fatigue and other context specific considerations. Most recently this has included “COVID resilience”; to minimise potential impact of COVID disruption. It is always satisfying looking at a challenging problem and developing workable solutions.

Nimbus Integration

We are pleased to announce that InterDynamics have recently partnered with nimbus to integrate FAID Quantum into nimbus’ time2work system. You can read more about the integration here.

Some good news for shift workers

Diet and exercise do make a difference!

We are constantly hearing about the health implications of shift work and poor sleep, and it is rarely good news. We know that shift workers are at increased risk of health problems, such as digestive upsets, obesity, cardiovascular disease, diabetes, depression and certain cancers, to name a few. However, two recent studies offer some hope.

A study published by the British Journal of Sports Medicine found that exercising according to World Health guidelines could help counteract adverse health outcomes associated with poor sleep. The study particularly looked at cardiovascular disease and cancer mortality. Both poor sleep and physical inactivity have previously been associated with health risks. The study found that while poor sleep is still associated with these negative health outcomes, engaging in moderate to high levels of physical activity appeared to minimise the risk.

Meal Timing
Another study, supported by the National Institutes of Health, looked at the impact of meal timing in night shift work. Eating at nighttime was found to boost glucose levels, while restricting meals to the daytime prevented the high blood sugar linked to night shift work. The effects on glucose are believed to be due to circadian misalignment. Restricting meals to the daytime, may therefore reduce health risks linked to night shift work, particularly diabetes.

Future Interventions
Although there is no substitute for sleep, and more research is needed, studies such as these do offer hope for shift workers. They could lead to practical interventions and assist shift workers to proactively influence their health outcomes.


  • Chellappa S, Qian J, Vujovic N, et al. (2021) Daytime eating prevents internal circadian misalignment and glucose intolerance in night work. Science Advances 7(49).
  • Huang B, Duncan MJ, Cistulli PA, et al. (2021) Sleep and physical activity in relation to all-cause, cardiovascular disease and cancer mortality risk. British Journal of Sports Medicine.
  • Hulsegge, G., Proper, K.I., Loef, B. et al. (2021) The mediating role of lifestyle in the relationship between shift work, obesity and diabetes. Int Arch Occup Environ Health 941287–1295.
  • Monnaatsie M, Biddle S, Khan S & Kolbe-Alexander T. (2021) Physical activity and sedentary behaviour in shift and non-shift workers: A systematic review and meta-analysis. Preventive Medicine Reports24.

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.

High physical activity levels may counter serious health harms of poor sleep

BMJ, Science Daily, June 2021
Physical activity levels at or above the weekly recommended amounts may counter the serious health harms associated with poor sleep quality, suggests a large long term study.

Moving more a shift in the right direction for shift workers

University of Southern Queensland, November 2021
A study by University of Southern Queensland researchers has highlighted the need to improve physical activity among shift workers.

Daytime meals may reduce health risks linked to night shift work

NIH, Science Daily, December 2021
A small clinical trial has found that eating during the nighttime — like many shift workers do — can increase glucose levels, while eating only during the daytime might prevent the higher glucose levels now linked with a nocturnal work life.

Blessed are the shift workers: but how well-rested are they?

Georgia Stynes, ABC, February 2022
In this audio discussion, Siobhan Banks, Director of the Behaviour-Brain-Body Research Centre at the University of South Australia, joined Georgia Stynes to talk about the relationship between sleep and shift workers. They also touch on the role of diet and exercise.

Issue #72- November 2021

Welcome to Focus on Fatigue!

It’s that time of year again! Some of us are springing forward, some of us are falling back and some are staying where they are!  And it’s all thanks to daylight saving!

Some people love it. Some people hate it. But we are all affected by it in some way, even if we don’t live in a place that observes daylight saving time.

In this month’s Focus on Fatigue, we will look at the ‘why?’ and the impact of all this strange time changing.

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).

Daylight saving

Why do we do it? And what’s the impact?

Daylight saving time changesWhat’s the point?

The main purpose of daylight saving time, (did you know it is daylight saving not daylight savings?) is to make better use of daylight. We change our clocks during the summer months to move an hour of daylight from the morning to the evening. This allows people to take advantage of light and warmth and participate in evening activity. However, originally the motivation for daylight saving was to save on the use and cost of artificial light.

History of daylight saving

Some people credit Ben Franklin with the invention of daylight saving, which is a bit of a stretch. However, he did write a satirical piece for the Journal de Paris in 1784, suggesting Parisians change their sleep schedules to save money on candles and lamp oil.

Daylight saving was first proposed in earnest by George Hudson in New Zealand in 1895. However, residents of Port Arthur, Ontario (now Thunder Bay) were the first to adopt a period of daylight saving time in 1908, followed by some other locations in Canada. Germany was then the first country to implement daylight saving, in 1916 during World War I, to minimize the use of artificial light to save fuel for the war effort. UK, France and other countries followed suit shortly after, with Australia and Newfoundland adopting daylight saving in 1917 and the U.S. in 1918. Many reverted back to standard time after the war. Since then, it has been adopted on and off in various places for different periods.

Current situation

Approximately 70 countries currently utilise daylight saving time (DST), or summer time, in at least part of the country. Countries near the equator are less likely to observe daylight saving. They have less need for it due to the warmer climate and more consistent daylight hours throughout the year. Even within countries that do observe daylight saving, it is often not adopted by all states and territories.

While the savings on energy may have originally been a valid justification, this advantage no longer stacks up. Our energy use has changed (more energy-efficient lighting, more electrical gadgets and energy sucking air conditioners), negating, or reversing, the energy saving benefit in some instances.

Divided opinions

Daylight saving remains an issue of contention in many places. It continues to be a topic of debate in Europe and America, with future changes likely. Some are pushing to abolish daylight saving time, while others are pushing to adopt daylight saving time all year round.


Daylight saving is problematic for farmers, who have lobbied against it from the beginning. It disrupts their schedules, particularly dairy farmers, and leaves less morning sunlight to get crops to market.

When it comes to conducting global business, constantly changing time zones also present challenges, and not all countries start/end daylight saving at the same time. This means the time difference between two locations can change four times in a year and the situation becomes further complicated when scheduling across multiple locations.

A number of studies have shown negative impacts relating to daylight saving. Most of these relate to the period immediately after the time change, resulting from disruption to circadian rhythm and sleep. Research suggests that the shift to daylight saving raises the instance of heart attack and other cardiac events. A study out of the US found a jump in fatal car crashes in the days following the shift to DST. And another study identified an increase in workplace injuries immediately following the switch to DST.

So, what’s the upside?

Along with those who enjoy the longer summer evenings, there are other benefits too. The extended evening light may result in an increase in physical activity in children and a decrease in robberies. Studies also found that it may result in fewer wildlife killed by vehicles and less road incidents.

Tips to adjust

For those who do have to go through the transition to and from daylight saving time, keep in mind these tips:

  • Start to slowly adjust your body clock in the few days leading up to the start of daylight saving by waking up a little earlier each day.
  • Eat a healthy breakfast first thing in the morning.
  • Spend time outdoors. Go for a walk in natural light.
  • With children, adjust slowly by putting children to bed a little earlier each day in the few days before the change, and reverse the process at the end of daylight saving.


  • Barnes, C. & Wagner, D. (2009) Changing to daylight saving time cuts into sleep and increases workplace injuries. Journal of Applied Psychology, 94(5), 1305–1317.
  • Buckle, A. (n.d.) History of Daylight Saving Time (DST). Time and Date. (Accessed 20/10/2021)
  • Chudow, J. Dreyfus, I. et al (2020) Changes in atrial fibrillation admissions following daylight saving time transitions, Sleep Medicine, 69, 155-158.
  • Doleac, J. & Sanders, N. (2015) Under the Cover of Darkness: How Ambient Light Influences Criminal Activity. The Review of Economics and Statistics 97(5), 1093–1103.
  • Ellis, A. et al. (2016) Daylight saving time can decrease the frequency of wildlife-vehicle collisions. Biology Letters, 12.
  • Ferguson, S., Preusser, D., Lund, A., Zador, P. & Ulmer, R. Daylight saving time and motor vehicle crashes: the reduction in pedestrian and vehicle occupant fatalities
  • Fritz, J., VoPham, T., Wright, K. & Vetter, C. (2020) A Chronobiological Evaluation of the Acute Effects of Daylight Saving Time on Traffic Accident Risk. Current Biology 30(4), 729-735.
  • Goodman, A., Page, A. & Cooper, A. (2014) Daylight saving time as a potential public health intervention: an observational study of evening daylight and objectively-measured physical activity among 23,000 children from 9 countries, International Journal of Behavioral Nutrition and Physical Activity, 11(1), 84.
  • Guven, C., Yuan, H., Zhang, Q., & Aksakalli, V. (2021) When does daylight saving time save electricity? Weather and air-conditioning. Energy Economics98.
  • Jiddou, M. R., Pica, M., Boura, J., Qu, L., & Franklin, B. A. (2013) Incidence of myocardial infarction with shifts to and from daylight savings time. The American journal of cardiology111(5), 631–635.
  • Kantermann, T., Juda, M., Merrow, M. & Roenneberg, T. (2007) The Human Circadian Clock’s Seasonal Adjustment is Disrupted by Daylight Saving Time. Current Biology, 17(22), 1996-2000.
  • Kotchen, M. & Grant, L. (2008) Does Daylight Saving Time Save Energy? Evidence from a Natural Experiment in Indiana. NBER.
  • Küfeoğlu, S., Üçler, S., Eskicioğlu, F., Öztürk, B. & Chen, H. (2021) Daylight Saving Time policy and energy consumption, Energy Reports, 7, 5013-5025.
  • Pacheco, D. (2020) Daylight Saving Time. Sleep Foundation. (Accessed 20/10/2021)

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

Daylight Saving Time Explained

CGP Grey, You Tube, October 2011
Every year some countries move their clocks forward in the spring, only to move them back in the autumn. To the vast majority of the world who doesn’t participate in this odd clock fiddling, it seems a baffling thing to do. So what’s the reason behind it?

Should we abolish daylight saving time – or apply it across Australia?

Nick Evershed, The Guardian, October 2021
These interactive graphics use sun position calculations to show how daylight saving affects daylight hours, and the effect of any changes

Study analyzes the potential consequences of canceling daylight saving time

Emily Henderson, News Medical, October 2021
A study by José María Martín-Olalla of the University of Seville has analyzed retrospectively and from a physiological perspective the potential consequences of canceling daylight saving time, the biannual change of clocks. In his conclusions, he argues that maintaining the same time during all twelve months could lead to an increase in human activity during the early morning in the winter months, with the potential repercussions on human health that this would entail.

Recent Studies Relating to Sleep and Fatigue

Meeting sleep recommendations could lead to smarter snacking

Ohio State University, Science Daily, September 2021
Missing out on the recommended seven or more hours of sleep per night could lead to more opportunities to make poorer snacking choices than those made by people who meet shut-eye guidelines, a new study suggests.

NASA Lab Studies Sleepiness and Use of Automated Systems

Abby Tabor, NASA’s Ames Research Center, September 2021
Drowsy driving accounts for a large proportion of car crashes, according to the National Highway Traffic Safety Administration. So, you might think self-driving cars would fix that. After all, computers just don’t get sleepy. But today’s vehicles are only partially automated, requiring the human driver to stay alert, monitor the road, and take over at a moment’s notice. A new study conducted by the Fatigue Countermeasures Lab at NASA’s Ames Research Center in California’s Silicon Valley suggests this passive role can leave drivers more susceptible to sleepiness – especially when they’re sleep deprived.

Issue #71 – September 2021

Welcome to Focus on Fatigue!

The benefit of fatigue education and training has come up in conversation with clients a couple of times recently. So, in this month’s Focus on Fatigue, we thought we would delve into the research to determine whether fatigue education is an effective fatigue management strategy.

Our ‘In the News’ section also features a recently released paper on “Guiding principles for determining work shift duration and addressing the effects of work shift duration on performance, safety and health” by the Academy of Sleep Medicine and the Sleep Research Society. This paper is a comprehensive review of fatigue risk management and a valuable resource, which we highly recommend reading.

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 Training

Is fatigue education and training effective in improving sleep, fatigue and safety outcomes?

An effective fatigue management system

An effective fatigue management system involves multiple layers of protection. One of these layers of protection is promoting and fostering a safety culture that recognises fatigue as a safety concern. Organisations and individuals that recognise fatigue as a safety concern are more likely to respond appropriately as fatigue-related risks escalate. A culture of concern can be stimulated by adequate fatigue education and training that focuses on managing fatigue-related risks for the organisation as well as the individual.

Studies on fatigue education & training

A number of studies have looked at the effectiveness of fatigue education and training in the workplace. These studies have been conducted in various industries including emergency medical services, health care, policing, trucking and aviation. The interventions varied in delivery method, length and content but included fatigue training and/or sleep health education.

Benefits of fatigue education and training

Some of the benefits observed following fatigue education and training programs were:

  • Improvements to patient safety and personal safety
  • Improvement in sleep quality
  • Reduction in ratings of acute fatigue, stress and burnout
  • Individuals more likely to identify and seek treatment for sleep disorders
  • Improvement in fatigue management knowledge, self-efficacy, attitude & behavioural intention

Factors influencing effectiveness of training

Certain factors were found to improve the effectiveness of training in some of the studies:

  • Training was found to be more effective when it included content specific to the work setting and tasks
  • Training delivered via lecture style or expert led training was more effective than other methods
  • Adoption of trained behaviour was more likely when supported by a company safety culture
  • Revisiting training every two years assisted retention of benefits

Fatigue education programs equip the individual with the tools and knowledge to proactively manage the effects of atypical work schedules. This assists in putting fatigue risk on the radar and reducing fatigue related incidence.


  • Arora, V. M., Georgitis, E., Woodruff, J. N., Humphrey, H. J., & Meltzer, D. (2007). Improving sleep hygiene of medical interns: can the sleep, alertness, and fatigue education in residency program help?. Archives of internal medicine167(16), 1738–1744.
  • Barger, L. K., Runyon, M. S., Renn, M. L., Moore, C. G., Weiss, P. M., Condle, J. P., Flickinger, K. L., Divecha, A. A., Coopler, P. J., Sequeira, D. J., Lang, E. S., Higgins, J. S. & Patterson, P. D. (2018) Effect of Fatigue Training on Safety, Fatigue, and Sleep in Emergency Medical Services Personnel and Other Shift Workers: A Systematic Review and Meta-Analysis, Prehospital Emergency Care22:sup1, 58-68.
  • Barger, L. K., O’Brien, C. S., Rajaratnam, S. M., Qadri, S., Sullivan, J. P., Wang, W., Czeisler, C. A., & Lockley, S. W. (2016) Implementing a Sleep Health Education and Sleep Disorders Screening Program in Fire Departments: A Comparison of Methodology. Journal of occupational and environmental medicine58(6), 601–609.
  • Fournier, PS., Montreuil, S. and Brun, JP. (2007) Fatigue Management by Truck Drivers in Real Life Situations: Some Suggestions to Improve Training. Work  29(3), 213 – 224.
  • Gander, P, Marshall, N, Bolger W & Girling I (2007) An evaluation of driver training as a fatigue countermeasure, Transportation Research Part F: Traffic Psychology & Behaviour, 8(1), 47-58.
  • Garbarino, S., Tripepi, G. & Magnavita, N. (2020) Sleep Health Promotion in the Workplace. International Journal of Environmental Research and Public Health, 17(21), 7952.
  • Hu, C. J., Lee, F. P., & Hong, R. M. (2020) Fatigue Management Health Education Intervention Effects on Flight Attendants. Aerospace medicine and human performance91(12), 911–917.
  • James, L., Samuels, C. H., & Vincent, F. (2018) Evaluating the Effectiveness of Fatigue Management Training to Improve Police Sleep Health and Wellness: A Pilot Study. Journal of occupational and environmental medicine60(1), 77–82.
  • Machin, M. (2017) A Evaluating a Fatigue Management Training Programme for Coach Drivers in L. Dorn (Ed), Driver Behaviour and Training, (pp. 75-83). Aldershot, UK: Ashgate
  • Smidt, M, Mitchell, D & Logan, K (2021) The Potential for Effective Training of Logging Truck Drivers, Journal of Agricultural and Biological Engineers, 27(1), 29-41.

Columbia River Bar Pilots See Value in Fatigue Training

InterDynamics recently conducted another successful fatigue training workshop with Columbia River Bar Pilots. Columbia River Bar Pilots have shown a strong commitment to fatigue management over many years and enlist InterDynamics to periodically conduct managing fatigue training workshops as part of this commitment.

Derek from Columbia River Bar Pilots offered the following reflection:
The Columbia River Bar Pilots employ a robust fatigue management system that benefits from periodic in-person training on fatigue and sleep science.  Healthy sleep promotes safety by improving alertness and decision-making to prevent accident and injuries to our pilots.”

InterDynamics’ Managing Fatigue Training Workshops have been successfully utilised across aviation, construction, energy, rail and marine industries; equipping participants with general awareness information on managing fatigue, as well as managing the social and lifestyle impacts of working shift work. The workshops provide personally relevant and practical techniques for managing individual fatigue.

Related Research

Effect of Fatigue Training on Safety, Fatigue and Sleep in Emergency Medical Services Personnel and Other Shift Workers: A Systematic Review and Meta-Analysis

Barger, L. K., Runyon, M. S., Renn, M. L., Moore, C. G., Weiss, P. M., Condle, J. P., Flickinger, K. L., Divecha, A. A., Coopler, P. J., Sequeira, D. J., Lang, E. S., Higgins, J. S. & Patterson, P. D. (2018)


Background: Fatigue training may be an effective way to mitigate fatigue-related risk. We aimed to critically review and synthesize existing literature on the impact of fatigue training on fatigue-related outcomes for Emergency Medical Services (EMS) personnel and similar shift worker groups.

Methods: We performed a systematic literature review for studies that tested the impact of fatigue training of EMS personnel or similar shift workers. Outcomes of interest included personnel safety, patient safety, personnel performance, acute fatigue, indicators of sleep duration and quality, indicators of long-term health (e.g., cardiovascular disease), and burnout/stress. A meta-analysis was performed to determine the impact of fatigue training on sleep quality.

Results: Of the 3,817 records initially identified for review, 18 studies were relevant and examined fatigue training in shift workers using an experimental or quasi-experimental design. Fatigue training improved patient safety, personal safety, and ratings of acute fatigue and reduced stress and burnout. A meta-analysis of five studies showed improvement in sleep quality (Fixed Effects SMD −0.87; 95% CI −1.05 to −0.69; p < 0.00001; Random Effects SMD −0.80; 95% CI −1.72, 0.12; p < 0.00001).

Conclusions: Reviewed literature indicated that fatigue training improved safety and health outcomes in shift workers. Further research is required to identify the optimal components of fatigue training programs to maximize the beneficial outcomes.

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.

AASM, Sleep Research Society Issue Guidance on Work Shift Duration for Employers

Matthew Gavidia, AJMC, July 2021
The Academy of Sleep Medicine and the Sleep Research Society issued guiding principles for employers on designing optimal work shift durations in the workplace, which address risk factors, countermeasures, and shared decision-making implications. The complete paper can be accessed here.

Owls and larks do not exist: COVID-19 quarantine sleep habits

AMHSI Research Team, Science Direct, January 2021
The coronavirus pandemic presented a unique opportunity to study the daily temporal patterns and sleep habits of humans. The question to be explored was: Are there discernible differences in sleep between the normal operational environment and the stay-at-home condition?

Issue #70 – July 2021

Welcome to Focus on Fatigue!

Do you rely on coffee, or another form of caffeine, to get you up and going in the morning, to counteract the mid afternoon slump or to get you through the night shift? If so, you are not alone! Caffeine is consumed by over 80% of U.S. adults.

Caffeine is a stimulant, widely known to help you stay awake and stave off tiredness. However, in this month’s Focus on Fatigue, we will look at how effective caffeine is in counteracting the affects of sleep deprivation and whether it has it’s limits.

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).

Caffeine can only do so much….

A recent study from MSU’s Sleep and Learning Lab has assessed how effective caffeine is in counteracting the negative effects of sleep deprivation on cognition. The study found that while caffeine counteracted impairment caused by sleep deprivation on a simple attention task (PVT), it did not significantly affect performance in a more challenging placekeeping task (UNRAVEL).

Placekeeping ability is a cognitive control process that plays a role in procedural performance, problem solving and other higher order tasks. It is the ability to perform the steps of a complex task in a prescribed order without skipping or repeating steps.

The study concluded that this finding “has implications for intervention research and suggests that caffeine has limited potential to reduce procedural error rates in occupational settings”.

While there are short term benefits to consuming caffeine during periods of sleep loss, it is worth being aware of caffeine’s limitations. Let’s break down what we know.

Caffeine can:

  • Increase alertness and reduce fatigue
  • Improve mood
  • Help maintain cognitive performance – Caffeine can help counteract degraded cognitive task performance due to sleep deprivation on vigilance tasks and simple tasks that require sustained focus and response.
  • Help maintain physical performance

However, caffeine can also…

  • Make you overconfident – Caffeinated people are more likely to feel confident about their work performance, even when that performance has suffered. This may have serious consequences in real-life situations where accurate self-perception is crucial for avoiding risks.

Caffeine does not:

  • Help with complex decisions – Caffeine does not help you make complex decisions in the face of changing information. While the effects of caffeine consumption on complex decision making have not been well researched, one study did find that a moderate dose of caffeine did nothing to reverse the effects of sleep deprivation in this sort of context. In other words, drinking coffee may make you feel alert, but it may not help you think more clearly in complex situations.
  • Improve performance in complex tasks – Caffeine does not appear to significantly counteract performance impairment, caused by sleep deprivation, in procedural performance, problem solving and other higher order tasks.
  • Replace sleep – Sleep gives your brain time to conduct a whole host of basic maintenance jobs that it simply cannot do when you’re awake.

While caffeine can be a useful tool, it does have it’s limitations and there is no real substitute for sleep!


  • Kamimori, G.H., McLellan, T.M., Tate, C.M. et al. (2015) Caffeine improves reaction time, vigilance and logical reasoning during extended periods with restricted opportunities for sleep. Psychopharmacology 2322031–2042.
  • Ker, K., Edwards, P. J., Felix, L. M., Blackhall, K., and Roberts, I. (2010). Caffeine for the prevention of injuries and errors in shift workers. Cochrane Database of Systematic Reviews, 5, CD008508.
  • Killgore, W. D. S., Lipizzi, E. L., Kamimori, G. H. and Balkin, T. J. (2007) Caffeine effects on risky decision making after 75 hours of sleep deprivation. Aviation, Space and Environmental Medicine, 78, 957-962.
  • McLellan, T., Caldwell, J. & Lieberman, H. (2016), A review of caffeine’s effects on cognitive, physical and occupational performance. Neurosicence & Biobehavioral Reviews, 71, 294-312.
  • Smith, A. (2002) Effects of caffeine on human behaviour. Food and Chemical Toxicology, 40(9), 1243-1255. http://doi.org10.1016/s0278-6915(02)00096-0
  • Smith, P. F., Smith, A., Miners, J., McNeil, J. and Proudfoot, A. (2000) The safety aspects of dietary caffeine. Expert Working Group on Caffeine. Australia New Zealand Food Authority. Canberra, Australia.
  • Stepan, M. E., Altmann, E. M., & Fenn, K. M. (2021). Caffeine selectively mitigates cognitive deficits caused by sleep deprivation. Journal of Experimental Psychology: Learning, Memory, and Cognition. Advance online publication.

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.

Don’t count on caffeine to fight sleep deprivation

Michigan State University, Science Daily, May 2021
Sleep scientists assessed how effective caffeine was in counteracting the negative effects of sleep deprivation on cognition.

How overwork is literally killing us

Christine Ro, BBC, May 2021
Alarming new research shows that people working more than 54 hours a week are at major risk of dying from overwork. It’s killing three-quarters of a million people each year.

How caffeine and alcohol affect your sleep

Matt Walker, Sleeping with Science, July 2020
Caffeine wakes you up, and alcohol makes you nod off, right? It’s not that simple. Sleep scientist Matt Walker takes us into the eye-opening ways that these drinks affect the quantity and quality of our sleep

Issue #69 – May 2021

Welcome to Focus on Fatigue!

Do you suffer from revenge bedtime procrastination? In this month’s Focus on Fatigue, we will look at what it is and how you can beat it.

Sleep well!

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).


Revenge Bedtime Procrastination


A new term has recently emerged and is circling the internet: ‘Revenge Bedtime Procrastination’.

Where did the term come from?

The term seems to have originated out of China by workers who work the 996 schedule (working from nine in the morning to nine in the evening, six days a week). They coined the term ‘bàofùxìng áoyè’, which translates ‘revenge bedtime procrastination’ or ‘retaliatory staying up late’. Use of the term spread rapidly last year after it was shared on twitter; obviously striking a chord with many!

What is it?

Revenge bedtime procrastination describes the phenomenon where people put off going to bed to carve out ‘me-time’ at the end of a busy day. For many, too tired to do anything intentional or productive, this time is spent mindlessly scrolling social media or watching tv.

Why ‘revenge’?

Those who work long hours can feel like they have little control over their time and are left with no leisure time. As a way of getting ‘revenge’, or fighting back, on this lack of control and free time, they stay up late.

What we know about bedtime procrastination

While the term ‘revenge bedtime procrastination’ may be relatively new, in 2014 a study by Dr Kroese was the first study to present bedtime procrastination as a possible cause for insufficient sleep. The study defined bedtime procrastination as “failing to go to bed at the intended time, while no external circumstances prevent a person from doing so”. This research concluded that “bedtime procrastination appears to be a prevalent and relevant issue that is associated with getting insufficient sleep”. Kroese also makes the point that bedtime procrastination is a particular challenge, as it occurs at the end of the day, when people typically have less mental energy or self-control strength.

Further research in 2018 found “that people who attempted to resist more desires (during the day) were more likely to engage in bedtime procrastination, suggesting that people may be less likely to stick to their intended bedtime after a particularly taxing day.”

How to stop self-sabotaging your sleep

Recommendations to combat bedtime procrastination often involve implementing a bedtime routine and practising basic sleep hygiene, such as maintaining a regular bedtime, having a relaxing pre-bedtime routine, avoiding screens before bed and avoiding caffeine in the hours before bed.

However, as revenge bedtime procrastination also has to do with a feeling of lack of control over one’s day, or lack of ‘me time’, finding ways to carve out such control and time in one’s day can also help. Perhaps by going for a walk during a lunch break, or adding some intention into the way time is spent after finishing work. Look at what is important to you, and intentionally make time for this, even if it is 20 minutes.

Employers can also help by recognising the importance of work/life balance and providing greater work flexibility.



  • Kamphorst, B., Nauts, S., De Ridder, D. & Anderson, J. (2018). Too Depleted to Turn In: The Relevance of End-of-the-Day Resource Depletion for Reducing Bedtime Procrastination. Frontiers in Psychology. 9, 252. http://doi:10.3389/fpsyg.2018.00252
  • Kroese, F., De Ridder, D., Evers, C. & Adriaanse, M (2014). Bedtime procrastination: introducing a new area of procrastination. Frontiers in Psychology. 5, 611. http://doi:10.3389/fpsyg.2014.00611
  • Kühnel, J., Syrek, C., & Dreher, A. (2018). Why Don’t You Go to Bed on Time? A Daily Diary Study on the Relationships between Chronotype, Self-Control Resources and the Phenomenon of Bedtime Procrastination. Frontiers in Psychology, 9, 77.
  • Suni, E., (2021). What is ‘Revenge Bedtime Procrastination’?, Sleep Foundation,


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.

Moonlight may affect sleep cycles

Harvard Health Publishing, April 2021
A recent study found that people fell asleep later and slept for less time over all in the three to five days leading up to a full moon.

Sleeping too little in middle age may increase dementia risk, study finds

Pam Belluck, NY Times, April 2021
The research, tracking thousands of people from age 50 on, suggests those who sleep six hours or less a night are more likely to develop dementia in their late 70s.

New study sheds light on how boredom affects bedtime procrastination and sleep quality

Eric Dolan, PsyPost, April 2021
New research suggests that the inability to be mindfully attentive to the present plays a role in compromised sleep quality. The study also indicates that boredom is an important predictor of bedtime procrastination.

Issue #68 – March 2021

Welcome to Focus on Fatigue!

While some people swear by the rejuvenating impact of a power nap, others maintain that napping leaves them feeling worse off than before. In this month’s Focus on Fatigue, we will take a look at the ins and outs of napping on the job and how to make your nap count.

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).


Napping for Success


The US Army recently released a new physical training manual, rebranded as the FM7-22 Holistic Health and Fitness manual, in which it promotes what the New York Times has coined as “strategic and aggressive napping”. The manual includes the following guidelines:

“When regular nighttime sleep is not possible due to mission requirements, Soldiers can use short, infrequent naps to restore wakefulness and promote performance. When routinely available sleep time is difficult to predict, Soldiers might take the longest nap possible as frequently as time is available”.

Whilst napping on the job is by no means a new phenomenon, official endorsement by organisations has grown in recent years. The healthcare industry has seen an increase in programs supporting workplace napping, and many companies, such as Google and Huffington Post, now have sleep pods available for use in their offices.

Research shows that a nap can reduce sleepiness, improve alertness, mood, performance and reaction time. For those working extended hours and shift work, the use of strategic naps can be an important, and sometimes critical, part of fatigue management. Here’s how to make your nap count.

Strategic Napping

Napping at work is most beneficial when it is a recognised part of an organisation’s fatigue management plan and appropriate facilities and support are provided.

Unlike a doze, a strategic nap is planned in advance. The timing and duration of the nap is determined by weighing the benefits of the nap against the potential negative consequences. A strategic nap also allows workers to coordinate with their colleagues and possibly arrange for any essential work activities to be covered while the planned nap is taking place. All of this helps workers to manage their fatigue effectively, and thus reduces risk.

Length of Nap

Recommendations on the ideal power nap length vary slightly, but are generally considered to be between 10 minutes and less than 30 minutes. Naps as short as 10 minutes have been shown to improve alertness and performance. Naps greater than 30 minutes, where an individual enters deeper sleep, increase the potential effects of sleep inertia (the grogginess felt upon awakening) and may require extra time after waking before returning to safety critical tasks. However, if circumstances allow, longer naps involving REM sleep have been shown to provide performance benefits for an extended period of time, as well as additional benefits such as boosting problem solving and creativity.

Timing of Nap

Napping is most likely to be successful if timed when your body’s drive to sleep is high. The body’s circadian rhythm promotes sleep during the night, with the strongest urge to sleep around 2 to 6am. There is also a secondary dip in alertness in the afternoon around 1 to 4pm, hence the popularity of an afternoon siesta in some cultures. By timing your nap for these circadian lows, it increases the likelihood of obtaining good quality sleep. However, waking during circadian lows can also increase the effects of sleep inertia. If you have a significant sleep debt and your drive to sleep is high, then sleep may also be successfully obtained at other times.

How about a Coffee Nap?

Having a coffee followed by a short sleep is more effective, in increasing cognitive performance and reducing sleepiness, than a nap alone. Coffee prior to a nap can also reduce the impact of sleep inertia on waking. The two work together to give that extra boost to get you through.

Downsides of Napping

There are two potential negative effects of napping that should be considered when deciding if, when and how long to nap for. These are: sleep inertia and the potential disruption to subsequent sleep.

Sleep InertiaThis is the grogginess and disorientation we feel when first waking from a nap. While under the effects of sleep inertia, task performance can be worse than if the person had not napped at all. Depending on the length of the nap, timing of the nap, stage of sleep you wake from and your level of sleep deprivation, sleep inertia can last from a few minutes up to an hour or longer. However, the effects greatly dissipate within 15-30 minutes in most cases.

If a nap is interrupted by an emergency requiring a quick response with a high level of performance, that person may end up responding to the emergency while suffering the effects of sleep inertia. Therefore, if this possibility exists, it will be necessary to weigh up the benefits of improved alertness and performance during regular work, with the likelihood of an emergency occurring during the period when sleep inertia is an issue.

Prior sleep deprivation exacerbates sleep inertia (the body just doesn’t want to wake up yet!). Therefore, staying ahead of sleep debt is one way to help reduce sleep inertia.

Disruption to subsequent sleep – Recovery sleep between shifts is essential to ensure that workers are ready for their next shift. Napping for long periods, or later in a shift, can disrupt the quantity and quality of subsequent sleep. This should be considered when timing naps.


  • Centofani, S., Banks, S., Coussens, S., et al. (2020) A pilot study investigating the impact of a caffeine-nap on alertness during a simulated night shift. Chronobiology International.  37(9-10), 1469-1473.
  • Geiger-Brown, J., Sagherian, K., Zhu, S., et al. (2016). CE: Original Research: Napping on the Night Shift: A Two-Hospital Implementation Project. The American journal of nursing116(5), 26–33.
  • Hilditch, C. J., & McHill, A. W. (2019). Sleep inertia: current insights. Nature and science of sleep11, 155–165.
  • Patterson, P. D., Weaver, M. D., Guyette, F. X., & Martin-Gill, C. (2020). Should public safety shift workers be allowed to nap while on duty?. American journal of industrial medicine63(10), 843–850.
  • Rosekind, M. R., Smith, R. M., Miller, D. L., et al. (1995) Alertness management: Strategic naps in operational settings. Journal of Sleep Research, 4, 62-66.
  • Sadeghniiat-Haghighi, K., & Yazdi, Z. (2015). Fatigue management in the workplace. Industrial psychiatry journal24(1), 12–17.
  • Signal, T. L., Gander, P. H., Anderson, H. and Brash, S. (2009) Scheduled napping as a countermeasure to sleepiness in air traffic controllers. Journal of Sleep Research, 18, 11-19.
  • Signal, T. L., van den Berg, M. J., Mulrine, H. M. and Garder, P. H. (2012) Duration of sleep inertia after napping during simulated night work and in extended operations. Chronobiology International, 29(6), 769-779.
  • Takahashi, M. (2012) Prioritizing sleep for healthy work schedules. Journal of Physiological Anthropology, 31(6).


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.

The Army Rolls Out a New Weapon: Strategic Napping

Dave Philipps, The New York Times, October 2020
Because fatigue can corrode mission performance, a new physical training manual tells soldiers to grab 40 winks when they can, part of a new holistic approach to health in the ranks.

A coffee and catnap keep you sharp on the nightshift, study suggests

University of South Australia, Science Daily, August 2020
A simple coffee and a quick catnap could be the cure for staying alert on the nightshift as new research shows that this unlikely combination can improve attention and reduce sleep inertia.

Why Do Coffee Naps Recharge You So Well?

SciShow, YouTube, June 2018
A short video explaining the benefits of coffee naps, and why they work so well. With their powers combined, coffee and naps create a greater sum than their parts.

NHS hospitals bring in sleep pods to help tired staff take a break

Denis Campbell, The Guardian, February 2020
Help is arriving for overworked NHS staff as a growing number of hospitals bring in sleep pods for doctors and nurses to grab power naps during their shifts.

Tired health care workers can recharge in private, comfortable space after pilot program brings sleeping pods to University Hospitals

Julie Washington,, October 2020
UH is the first hospital system in the country to install HOHM sleeping pods in a pilot program that put three pods on UH’s main campus in September 2020.

South African Gold Mine Operations Scheduling

Real time job allocation in underground wet mine.

Bluescope Steel Loco Analysis

Examining plant machinery end of life replacement alternatives for optimum economic viability

Hanson Block Production Planner

Enhancing multi site production operations using historical information and future growth projections

Assigned Services Planning Tool – Workforce Scheduling

Assisting railway engineers/train drivers to have a better work life balance.

Iron Ore Supply Chain

Optimizing complex supply chains to meet short and long term planning goals.