Focus on Fatigue

Welcome to Focus on Fatigue!

Another big year will soon draw to a close. Down here in Australia, that means summer sun and beach fun. Wherever you are in the world, the staff of InterDynamics would love to take this opportunity to wish you and your family a joyful festive season and a safe, well-rested start to the new year.

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

Long sleepers: Are they getting too much of a good thing?

The saying goes that everything is good for you in moderation. This holds true for most things. Too much food makes us overweight and too little robs us of energy, but the right amount keeps us healthy and active. Too little exercise leads to all sorts of nasty health issues and too much gives us blisters and bad knees. A moderate amount of exercise keeps us fit and strong. What about the third pillar of the healthy living triad? Sleep.

Most of us know the importance of sleep, perhaps because we are now bombarded with information every other day about the dangers of sleep deprivation. Hence we strive, and sometimes succeed, to achieve the recommended 7-9 hours. There are some people, on the other hand, who not only love their sleep but are experts at getting it. Nine hours a night? Ten, perhaps? No problem. But are all these snoozing hours actually doing more harm than good? Is too much sleep bad for you?

As it turns out, a number of researchers have asked this question over the last few decades and most agree the short answer is yes. Too much sleep is, indeed, a bad thing. Much of the research in this area has looked at the issue in terms of mortality rates. They’ve found that, over a long-period of time (anywhere from 4-25 years, depending on the study) people who sleep a lot are more likely to die than those who get the recommended amount of sleep. People who sleep too little are also more likely to die, but the association is actually stronger for the long sleepers than it is for the short sleepers. This is especially true for older adults (45+ years).

Why is sleeping a lot bad for you?

This is the part where research has yet to provide an adequate answer. In fact, some suggest that sleeping a lot may be a symptom of ill-health rather than the cause. In other words, does sleeping too much cause health problems, or do health problems make people sleep a lot? This is an area which requires more research.

How much is too much sleep?

Here is where things get even trickier. The Sleep Health Foundation states that “most adults require between 7 and 9 hours a night to feel properly refreshed and function at their best the next day.” Many of the studies quoted in the research use ‘more than 8 hours’ as the basis for their analyses, which would make nine hours of sleep seem like a risky proposition. However, one meta-analysis found that the association between long sleep and mortality seemed to strengthen as the hours of sleep increased. So, if you’re sleeping between 7 and 9 hours each night and you feel refreshed and ready to get out of bed each morning, you’re probably in the clear. If you regularly sleep longer than 9 hours, however, it might be a good idea to have a health check-up.

Does this mean I should avoid ‘catching up’ on sleep?

You absolutely should continue to catch up on sleep if you’ve been deprived (caveat: it’s always better to avoid becoming sleep deprived in the first place). These studies were looking at people who regularly sleep for longer than the recommended hours each night. For them, excessive sleep was the norm, not the exception.

I’m a long sleeper! What should I do?

If you regularly sleep longer than nine hours every night, it might be a good idea to chat to your local health care professional. It’s possible that the quality of your sleep is low and that’s why you spend so much time asleep, or that the extra sleep is caused by some underlying health issue. It’s also possible that, genetically speaking, that’s just the way you were made.


  • Youngstedt, S. D. and Kripke, D. F. (2004) Long sleep and mortality: Rationale for sleep restriction. Sleep Medicine Reviews, 8(3), 159-174.
  • Ding, D., Rogers, K., van der Ploeg, H., Starnataskis, E. and Bauman, A. E. (2015) Traditional and emerging lifestyle risk behaviors and all-cause mortality in middle-aged and older adults: Evidence from a large population-based Australian cohort. PLOS Medicine, 12(12), e1001917. DOI: 10.1371/journal.pmed.1001917.
  • Gallicchio, L. and Kalesan, B. (2009) Sleep duration and mortality: A systematic review and meta-analysis. Journal of Sleep Research, 18, 148-158.
  • Cappuccio, F. P., D’Elia, L., Strazzullo, P. and Miller, M. A. (2010) Sleep duration and all-cause mortality: A systematic review and meta-analysis of prospective studies. Sleep, 33(5), 585-592.

InterDynamics News

Conferences and presentations

Sleep Down Under

Last month InterDynamics attended the Sleep Down Under Conference in Brisbane, Australia. Sleep Down Under was the 30th Annual Scientific Meeting of the Australasian Sleep Association (ASA) and Australasian Sleep Technologists Association (ASTA). Staff who attended enjoyed hearing all the latest research on topics such as nutrition for shift workers, individual management, and the wonders of the circadian rhythm.

Date: 17-20 October 2018
Venue: Brisbane Convention and Exhibition Centre, Brisbane, Australia

More information can be found on the conference website.

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 you get too much sleep?

SciShow, YouTube (24 December 2016)

Are you someone who likes to hit the snooze button four or five times before waking up? Do you have to be physically pulled out of bed every morning? Do you ever wonder if that’s normal and healthy? Well, this episode is for you!

Article: Why eight hours a night isn’t enough, according to a leading sleep scientist

Georgia Frances King, Quartz (10 June 2018)

For something that we spend a third of our lives doing (if we’re lucky), sleep is something that we know relatively little about. To set the record straight about being horizontal, Quartz spoke to Daniel Gartenberg, one of the world’s most-talked-about sleep scientists.

Welcome to Focus on Fatigue,

Sometimes in life we have little choice but to keep on keeping on, even when we’re tired. Perhaps we’re in the car, still an hour away from home. Or maybe we need to finish a project and absolutely cannot miss the deadline. Is there an effective way to keep our alertness and performance levels up long enough to reach our goal safely? That is the question we’ll be investigating in this month’s Focus on Fatigue.

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

The Power of the Coffee Nap

In the midst of our busy working days (and working nights), many of us reach for a cup of coffee, or other caffeinated beverage, to counteract sleepiness. If the sleepiness reaches a high enough level, we may go even further and have a quick nap before returning to our task. But what would happen if we did both? Would combining the two techniques achieve an outcome greater than the sum of its parts?

What is a coffee nap?

Taking a coffee nap is a simple two-step process.

Step One: Drink a cup of coffee. This must be done quickly, so make sure it’s not too hot, or switch out your latte for an iced coffee, or a simple espresso shot. Drinking tea is not as good an option here simply because the caffeine content will not be high enough to achieve the desired effect.

Step Two: Take a nap. The nap itself should be no more than twenty minutes. This ensures you don’t enter the deeper stages of sleep, which would lead to grogginess (known as sleep inertia) upon waking. Setting an alarm on your phone is a great way to prevent oversleeping.

Why do coffee naps work?

Adenosine is a molecule produced by your brain when you’re awake and active. As adenosine builds up, it fits into receptors in the brain, making you tired. The caffeine molecule is similar in shape so, when you drink a cup of coffee, the caffeine makes its way to your brain and competes with the adenosine for access to the same receptors. The more caffeine molecules reaching the receptors, the greater the alerting effect.

Here’s where the nap can help. Sleep naturally flushes adenosine out of your brain, making way for more caffeine molecules to find available receptors. The caffeine takes about 30 minutes to be absorbed through your small intestine, pass into your bloodstream, and reach your brain. Therefore, if you have a 15-20 minute nap, the adenosine levels will be reduced just in time for the caffeine to sweep in and save the day. Hooray!

How well do coffee naps work?

The coffee nap has been found to be effective in a variety of situations, including:

  • preventing performance degradation on computer tasks for at least one hour
  • reducing sleepiness and improving performance in drivers during a monotonous afternoon drive in a car simulator for one hour
  • in a study of night shift workers, caffeine and naps were both found to improve performance on a vigilance task and decrease sleepiness, but the combination of the two had the greatest effect

It’s important to note that while coffee naps can alleviate sleepiness in the short term, they are not a replacement for adequate sleep, and the effects will wear off within a couple of hours.

What if I’m a bad napper?

Many people find it difficult to nap on command, especially during the day. However, the research has found that even a restful doze can help performance.

So, the next time you find yourself needing to go that extra hour or two before resting, try a coffee nap. It may just do the trick.


  • Hayashi, M., Masuda, A. and Hori, T. (2003) The alerting effects of caffeine, bright light and face washing after a short daytime nap. Clinical Neurophysiology, 114(12), 2268-2278.
  • Reyner, L. A. and Horne, J. A. (1997) Suppression of sleepiness in drivers: Combination of caffeine with a short nap. Psychophysiology, 34(6), 721-725.
  • Newman, R. A., Kamimori, G. H., Wesensten, N. J., Picchioni, D. and Baklin, T. J. (2013) Caffeine gum minimized sleep inertia. Perceptual and Motor Skills, 116(1), 280-293.
  • Schweitzer, P. K., Randazzo, A. C., Stone, K., Erman, M., and Walsh, J. K. (2006) Laboratory and field studies of naps and caffeine as practical countermeasures for sleep-wake problems associated with night work. Sleep, 29(1), 39-50.
  • Stromberg, J. (2015) Scientists agree: Coffee naps are better than coffee or naps alone. Vox. (Accessed: 1 August 2018)

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: Health Check: What are ‘coffee naps’ and can they help you power through the day

Chin Moi Chow, The Conversation (3 April 2017)

Caffeine and napping have something in common. Both make you feel alert and can enhance your performance, whether that’s driving, working or studying. But some people are convinced that drinking a coffee before a nap gives you an extra zap of energy when you wake up.

Video: Why do coffee naps recharge you so well?

SciShow, YouTube (23 June 2018)

A short video explaining the benefits of coffee naps, and why they work so well.

Welcome to Focus on Fatigue!

We’ve all experienced moments in our lives when we’ve felt the urge to go to sleep at an inappropriate time. It could happen in a meeting, during a movie, or when we hit that mid-afternoon slump. At these times one of the methods we tend to use to keep the sandman away is to get up and walk around, maybe even do some stretches. This sort of low-level exercise often helps increase our alertness long enough to finish the task at hand. In this issue of Focus on Fatigue we’ll look at how useful low-level exercise can be in assisting shift workers to maintain alertness and concentration during their shift.

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

Exercising on the Job

Every shift worker knows what it’s like to experience moments of fatigue in the workplace. These moments can be caused by issues such as sleep deprivation, working at odd hours, or by the need to complete monotonous tasks for a long period of time. A variety of behaviours have proved effective at reducing fatigue, including strategic napping, exposure to bright light, and eating a healthy snack. Another behaviour which can be useful is low-level exercise. While this topic has not received extensive research attention, several studies have shed light on how exercise at work can be used by night shift workers.

Sato and his colleagues (2010) conducted a study in which participants worked between the hours of 10pm and 8am. They performed tasks requiring sustained attention while sitting down. The participants were separated into two groups, those who spent three minutes exercising for each hour of work, and those who did not exercise at all. It was found that the exercisers performed their work better than those who did not exercise. This was true even though the exercisers felt just as fatigued and sleepy as the non-exercisers.

Another study examined the ability of young people to stay awake for up to 31 hours using varying degrees of physical activity. Simply being spoken to (no physical activity) was the least effective, followed by sitting up and then standing up. Wakefulness was enhanced most by standing and doing knee bends. Therefore, the more intense the level of activity, the more effective it was in helping participants maintain wakefulness.

It is, of course, important for individuals to assess what sort of activity is most helpful for them based on the type of work they do. Indeed, the inclusion of low-level exercise may be most helpful for those performing sedentary tasks, but less useful for shift workers who already move around while working.

What kind of exercises help?

The exercises performed by the participants of the Sato study were as follows:

  • Neck twisting – turning head from side to side;
  • Arm swinging – swinging outstretched arms around in circles;
  • Leaning backwards and forwards – bending at the waist;
  • Twisting the torso – lift arms up and bend at waist to one side, then the other;
  • Bending and stretching the knees – squatting and standing;
  • Side stretching the legs – squat down on one knee and stretch other leg straight out to the side;
  • Stretching the lower legs – stretch one straight leg out behind and bend front knee till a stretch is felt in the back leg;
  • Spreading the legs – lunging squats; and
  • Deep breathing – done while standing tall.

Each exercise was performed for approximately 20 seconds and was designed to be performed in a small space (within a radius of 1.5m).


  • Bonnet, M. H. and Arand, D. L. (1999) Level of arousal and the ability to maintain wakefulness. Journal of Sleep Research, 8, 247-254.
  • Sato, T., Kubo, T., Ebara, T., Takeyama, H., Inoue, T., Iwanishi, M., Tachi, N., Itani, T. and Kamijima, M. (2010) Brief hourly exercise during night work can help maintain workers’ performance. Industrial Health, 48, 470-477.

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: A sleep doctor’s No. 1 tip for a great rest every night

Dr Michael J. Breus, MindBodyGreen (1 January 2018)

As a board-certified sleep specialist, I could share a copious amount of advice to enhance your sleep; however, if you choose only one thing to improve, make it getting 30 minutes of aerobic exercise.

Video: How exercise rewires your brain

Seeker, YouTube (9 July 2013)

Everyone knows exercise is good for your health, but new studies show it does more than flatten those abs– it physically alters your brain to better handle stress! Anthony shows us this hidden, and hugely beneficial impact of working out.

Welcome to Focus on Fatigue!

Here at Focus on Fatigue we spend a lot of time talking about the benefits of getting enough sleep and how everyone, shift workers and non-shift workers alike, should make sleep a priority. But what about those times when you have the opportunity to sleep but the sandman fails to show up? This can result in frustration and worry, especially as the minutes continue to tick by. In this issue of Focus on Fatigue we’ll be looking at insomnia: what it is and what shift workers can do to prevent it from becoming a problem.

The FRMS Team


InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 2 8404 0400 Ext 23

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

Insomnia and Shift Work

We’ve all experienced nights when we can’t get to sleep, no matter how long we lie in bed wishing it would happen. Other times we’ve woken up hours before dawn and not been able to go back to sleep. For some people, however, these sorts of sleeping difficulties are a nightly struggle and this is when the term ‘insomnia’ comes into play. Around 6% of the adult population meet the diagnostic criteria for insomnia. For shift workers, however, estimates rise as high as 20%. Insomnia is also a major component of shift work disorder.

Consequences of insomnia

The consequences of insomnia are varied, including psychosocial, occupational, health and economic repercussions. While those who suffer from insomnia are faced with the same symptoms as anyone experiencing sleep deprivation, such as daytime sleepiness and irritability, the long-term nature of insomnia introduces more far-reaching problems. Insomniacs tend to take more frequent sick leave and use health care resources more often. There is an increased risk of accident and, over time, an increase in the risk of developing depression, anxiety, and substance-related problems. In recent research, the sleep deprivation experienced in sleep disorders such as insomnia has also been linked to an increased risk of Alzheimer’s disease later in life.

How much sleep are insomniacs really getting?

One surprising finding of insomnia research is that most (but not all) people who suffer from insomnia have a surprisingly limited ability to accurately estimate the amount of sleep they’re getting. They will often overestimate their sleep onset latency (how long it takes them to fall asleep) and underestimate their total sleep time (compared to objective measures of sleep such as a polysomnograph). In contrast, normal sleepers are usually able to perceive their sleep more accurately. A review of the research surrounding this issue concluded that such misperceptions are likely caused by misinterpreting sleep as wakefulness, worry causing a distortion in perceived time, and an increase in brief awakenings in the initial onset of sleep. These misperceptions regarding sleep do not, however, decrease the distress caused by the disorder; nor does it relieve the adverse outcomes associated with it.

Preventing insomnia in shift workers

A recent review of non-pharmacological preventions for fatigue and insomnia in shift workers included the following interventions:

  • Napping – A 20-minute nap during a shift can improve alertness, vigilance, reaction times, and performance and decrease the risk of accidents. Although, sleep inertia should be taken into consideration upon waking.
  • Nutrition – The use of caffeine at the start of a shift can be helpful, as well as high-protein meals and maintaining a wholefood diet. Regular normal day and night eating patterns should be maintained wherever possible.
  • Light – Planned exposure to bright light can assist shift workers in making adjustments to their internal clock to reduce sleepiness during work shifts.
  • Lifestyle training – Holistic training programs can help give shift workers tools to cope with the challenges of shift work, including good nutrition, managing fatigue, and sleep hygiene.
  • Cognitive and behavioural interventions – A variety of behaviours, such as exercise, can help to prevent insomnia. Shift workers can also use interventions such as timing their work breaks, social interaction during breaks, and sensory stimulation.


  • Vallieres, A., Azaiex, A., Moreau, V., LeBlanc, M., and Morin, C. (2014) Insomnia in shift work. Sleep Medicine, 15(12), 1440-1448.
  • Belcher R, Gumenyuk V, Roth T. (2015) Insomnia in shift work disorder relates to occupational and neurophysiological impairment. Journal of Clinical Sleep Medicine, 11(4), 457–465.
  • Harvey, A. and Tang, N. (2012) (Mis)Perception of sleep in insomnia: A puzzle and a resolution. Psychological Bulletin, 138(1), 77-101.
  • Richter, K., Acker, J., Adam, S., and Niklewski, G. (2016) Prevention of fatigue and insomnia in shift workers—a review of non-pharmacological measures. The EMPA Journal, 7(16).

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: If you have insomnia, don’t sleep more, sleep efficiently, study on soldiers finds

J. P. Lawrence (24 June 2017) San Antonia Express News

A new study on sleep suggests the best way to cure insomnia is to get out of bed. Often those with insomnia spend long hours in bed, but few actually spent sleeping. Spending more time tossing and turning can actually make insomnia worse, because over time, people begin to associate bedtime with frustration and anxiety, the researcher said.

Video: How to sleep better – Fixing insomnia

PictureFit (26 January 2017) YouTube

Learn about insomnia and how you can fix it today. Insomnia is a huge problem for many people around the world. Roughly 95% of all Americans deal with insomnia in one point of their lives. It’s time to fix it and get a good night’s rest!

Welcome to Focus on Fatigue,

It’s a brand-new year and many of us will spend time this month deciding what areas of life or work we wish to focus on in the coming twelve months. There is, however, one important thing we should all do before making any important decisions: get a good night’s sleep. This month in Focus on Fatigue we’ll look at how sleep deprivation can affect the decisions we make.

The FRMS Team


InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 2 8404 0400 Ext 23

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

Sleep and Decision Making

Many studies have attempted to explore the effects of sleep deprivation on decision making. So far researchers have found that sleep deprivation will produce the greatest detrimental effects under the following conditions:

Dull, monotonous tasks

The more basic and monotonous a task is, the more likely it is that sleep deprivation will make you perform badly. Performance can be improved if the person is motivated to do well.

Boredom or lack of motivation

Interesting tasks seem to be largely immune to sleep deprivation, as long as they are not too complex and are rule-based. However, even interesting tasks become dull and monotonous over time. Again, unless the motivation to do well is present, performance will begin to suffer.

Complex tasks with changing circumstances

The prefrontal cortex is the part of the brain that helps you to focus your attention on a given task for long periods of time. It also deals with novelty and the unexpected. During wakefulness, it is one of the hardest working parts of the brain.

This area of the brain is restored by deep sleep, which means that when you are sleep deprived, the prefrontal cortex is one of the first parts of the brain to suffer. Therefore, you could be affected in any of the following ways:

  • Impaired language skills-communication
  • Lack of innovation
  • Inflexibility of thought processes
  • Inappropriate attention to peripheral concerns or distraction
  • Over-reliance on previous strategies
  • Unwillingness to try out novel strategies
  • Unreliable memory for when events occurred
  • Change in mood including loss of empathy with colleagues
  • Inability to deal with surprise and the unexpected

The consequences of impaired decision making in the presence of sleep deprivation have been seen time and again throughout history. As summarised by Harrison and colleagues (2000):

“It is perhaps just a coincidence that some of the most renowned man-made disasters or near disasters concerning nuclear power plants, such as Chernobyl, Three Mile Island … all occurred in the early morning and involved human error in failing to contain otherwise controllable but unexpected and unusual mechanical or control room malfunctions. With all four, experienced control room managers misdiagnosed and failed to appreciate the extent of the fault and then embarked on courses of action that were inappropriate and continued to persevere in this way in spite of clear indications that their original assessment was wrong.” (p. 247)

Will coffee help?

When a person is in a position where they are sleep deprived and forced to make complex decisions, it is understandable that they will reach for a cup of coffee to help them cope with the demands that are being placed upon them. While the effects of coffee in such a situation 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 situation. In other words, drinking coffee may make you feel more alert, but it may not do anything to help you think more clearly.

What if I take a nap?

A nap does have the benefit of improving alertness, performance and mood. However, the nap will always be followed by a period of sleep inertia. How long this inertia lasts depends on the severity of the sleep deprivation, the length of the nap, and the sleep stage the person was in right before they woke up.

If a worker’s scheduled 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. In this case, their job performance may be worse than if they had not napped at all.

Therefore, if this possibility exists, it will be necessary to weigh up the benefits of improved alertness and performance during regular work, with the potential likelihood of an emergency occurring during the period when sleep inertia is an issue.


  • Harrison, Y. and Horne, J. A. (2000) The impact of sleep deprivation on decision making: A review. Journal of Experimental Psychology: Applied, 6(3), 236-249.
  • Killgore, W. D. S., Balkin, W. J. and Wesensten, N. J. (2006) Impaired decision making following 49 h of sleep deprivation. Journal of Sleep Research, 15, 7-13.
  • 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.
  • Whitney, P., Hinson, J. M., Jackson, M. L. and Van Dongen, H. P. A. (2015) Feedback blunting: Total sleep deprivation impairs decision making that requires updating based on feedback. SLEEP, 38(5), 745-754.

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: Research shows sleep loss impedes decision making in crisis

Will Ferguson (7 May 2015) Washington State University

WSU researchers created a laboratory experiment that simulates how sleep loss affects critical aspects of decision making in high-stakes, real-world situations. Their results provide a new understanding of how going without sleep for long periods can lead doctors, first responders, military personnel and others in a crisis situation to make catastrophic decisions.

Welcome to Focus on Fatigue,

One of the main challenges shift workers face is keeping their energy levels high through those long shifts, especially at night. Maintaining a healthy diet is a great way to assist in this area. However, with another year drawing to a close and all those silly season celebrations close at hand, it can be difficult to eat a good variety of healthy foods. In this month’s Focus on Fatigue, we’ll look at the impact of shift work on our nutrition, and ways in which shift workers can stay healthy and alert at work.

Here at InterDynamics, we would also like to take this opportunity to wish you and your family a very happy Christmas and New Year period.

The FRMS Team



InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 2 8404 0400 Ext 23

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

Eating on the Job

Maintaining a healthy diet is one of the many challenges faced by shift workers around the globe. A number of the negative health consequences associated with shift work – such as obesity (especially abdominal obesity), type 2 diabetes and cardiovascular disease – also have poor diet as a risk factor.

There are many reasons why a healthy diet can be difficult to maintain when working shifts, including:

  • Lack of access to healthy food (in the middle of the night the only food available may come from a vending machine);
  • Lack of time/motivation for preparing food to bring in from home;
  • The need to eat quickly or while on the move;
  • Lack of time to eat at all due to work demands; and/or
  • Lack of appropriate food storage/preparation areas at work.

Nutrition and the Circadian Rhythm

The human circadian rhythm (our internal body clock) has a major influence on when we feel alert and when we feel sleepy. It turns out the circadian rhythm also play a part in when we feel hungry. This can be problematic for shift workers who finds themselves trying to eat ‘lunch’ at midnight. Indeed, shift-workers have been found to be more likely to develop gastric problems.

In one study, participants were asked to rate their appetite and food preferences during a 13-day period. It was found that appetite tended to be lowest at around 8am and peaked at 8pm, leading to the desire to eat a larger meal at night. It was suggested that this greater appetite before sleeping helps us to make it through the night without waking due to hunger, while the lack of hunger in the morning prevents us from being overly ravenous when we wake up. Another study looked at the appetite of shift workers who worked either day shifts, early morning shifts, or night shifts. It was found that those who worked the early morning shift tended to have the lowest appetites and were more likely to eat fatty foods.

In keeping with this idea that the body’s need for food decreases through the night to a low-point in the morning, shift workers have been found to use ‘nibbling behaviour’ during night-shifts, rather than eating full meals. Assuming they are nibbling on healthful foods, this may assist workers in consuming their daily requirement of calories in a more comfortable manner than if they attempted to eat a heavy meal in the middle of the night.

Food Choices

Shift workers have been found to have a tendency to eat more inflammatory diets than non-shift workers. This includes an increased consumption of calories, fats, proteins, carbohydrates, and sweets. They can also be less likely to consume vegetable and fruits, but more saturated fats, than their day-working counterparts.

Another study found that the food intake of night workers was more likely to be influenced by habit and time availability, than by hunger. They were more dependent on snacks than day workers, looked forward to their meals less and felt more bloated after eating. These effects were still present, to a lesser degree, on their rest days.

What can shift workers do to stay healthy?

Diabetes Australia has published a short guide to nutrition for shift workers. You can download the guide here. Below are some of the tips given for making sure your shift working nutrition plan is good for you:

  • Eat every 3-4 hours, including 3 main meals and 2-3 snacks in each 24-hour period
  • Eat according to the time of day: breakfast in the morning, lunch in the middle of the day and dinner in the evening
  • If you’re eating late at night, when you would normally be sleeping, aim for a snack that’s high in protein instead of a full meal
  • Eat a small meal after your shift so you don’t go to bed hungry
  • Keep an eye on your portion sizes
  • Drink more water than any other drink
  • Limit sugary drinks, alcohol and caffeine
  • Avoid caffeine within the six hours before going to sleep

The Shifting Nutrition guide also includes meal ideas and more information on the different types of food shift workers should aim to consume and in what quantities.


  • Crispim, C. A., Waterhouse, J., Damaso, A. R., Zimberg, I. Z., Padilha, H. G., Oyama, L. M., Tufik, S. and de Mello, M. T. 2011) Hormonal appetite control is altered by shift work: A preliminary study. Metabolism Clinical and Experimental, 60, 1726-1735.
  • Diabetes Australia (2015) Shifting Nutrition: A Shift Workers Guide to Nutrition. Queensland Government.
    Hemio, K., Puttonen, S., Viitasalo, K., Harma, M., Peltonen, M. and Linstrom, J. (2015) Food and nutrient intake among workers with different shift systems. Ocuppational and Environmental Medicine, 72(7), 513-520.
  • Reinberg, A., Migraine, C., Apfelbaum, M., Brigant, L., Ghata, J., Vieux, N., Laporte, A. (1979) Circadian and ultradian rhythms in the feeding behaviour and nutrient intakes of oil refinery operators with shift-work every 3-4 days. Diabete & Metabolisme, 5(1), 33-41.
  • Scheer, F. A. J. L., Morris, C. J. and Shea, S. A. (2013) The internal circadian clock increases hunger and appetite in the evening independent of food intake and other behaviors. Obesity, 21, 421-423.
  • Sun, M., Feng, W., Wang, F., Li, P., Li, Z., Li, M., Tse, G., Vlaanderen, J., Vermeulen, R., and Tse, L. A. (2017) Meta-analysis on shift work and risks of specific obesity types. Obesity Reviews, doi: 10.1111/obr.12621.
  • Waterhouse, J., Buckley, P., Edwards, B. and Reilly, T. (2003) Measurement of, and some reasons for, differences in eating habits between night and day workers. The Journal of Biological and Medical Rhythm Research, 20(6), 1075-1092.
  • Wirth, M. D., Burch, J., Shivappa, N., Steck, S. E., Hurley, T. G., Vena, J. E. and Hebert, J. R. (2014) Dietary inflammatory index scores differ by shift work status: NHANES 2005 to 2010. Journal of Occupational and Environmental Medicine, 56(2), 145-148.

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: Shift work: How to stay healthy while working round the clock

The Guardian, 22 June 2017

Shift work: it’s complicated. Are you “working” when you’re asleep but at work? Should you be paid for being on call when you’re at home? Recent legal cases have looked at whether a sleepover shift is “working time” (and therefore, the worker should be entitled to the national minimum wage) and there’s new research on shift workers and their health too. A recent study found that delaying meals because of working shifts can mess with your internal body clock. But what if you can’t avoid shift work? What if your job kicks off in the evening and ends at dawn, and that’s just the way it is? Try these six ways to survive the slog.

Welcome to Focus on Fatigue,

There’s nothing better in the height of summer than a tall glass of cold water. During the winter months, however, we may reduce our water intake or find ourselves turning to drinks other than plain water (such as hot tea) to slake our thirst. The importance of staying hydrated is well-known, but how do we know when we’ve drunk enough? And do the type of liquids we consume make a difference? This month in Focus on Fatigue we will look at ways to stay hydrated year round, no matter what we’re drinking.

The FRMS Team



InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 2 8404 0400 Ext 23

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

Water: How Much is Enough?

Water makes up a large portion of the human body, ranging from 75% when we are born, to around 55% as we age. It is essential for many bodily functions, including digestion, absorption of nutrients, and thermoregulation. Every day we lose water through natural processes such as perspiration, breathing and the elimination of waste. Therefore, we must continually replace this water through eating and drinking. Failure to replace this water would result in death within a few days. But how much water do we need to consume to ensure our bodies maintain optimum hydration levels?

How much water do we need?

The Australian Government has suggested that adult men should consume 3.4 litres of water each day (including 2.6L of fluid) and adult women should consume 2.8 litres per day (including 2.1L of fluid). This recommendation was based on the median intake from a National Nutrition Survey. Does this mean that if you aren’t drinking litres of water each day, that you’re at risk of dehydration? Not necessarily.

There is no proven level of water intake that would ensure adequate hydration for all people. Therefore, individuals should consider several other factors when looking at their water intake. This includes personal factors such as size and the amount of physical exercise you do, as well as environmental factors like heat.

It’s important to remember that we get about 20% to 25% of our daily water intake from the food we eat. Also, the fluid portion of our water intake does not come just from plain water alone. For example, we are consuming water when we put milk on our breakfast cereal, when we have a cup of coffee, or when we drink a soft drink.

When drinking fluids other than plain water, however, it is important to consider what is being consumed with the water. For example, milk provides the body with calcium and other essential nutrients, while soft drink is largely made up of sugar which may lead to a high caloric intake and other health problems. The amount of caffeine contained in beverages should also be considered, to prevent the consumption of unsafe levels.

What are the effects of mild dehydration?

Many researchers have studied the effects of mild dehydration on the human body. This often involves achieving a body mass loss of one or more percent through exercise and/or diuretics. Such research has found that mild to moderate dehydration can negatively affect short-term memory, mood, concentration, alertness, perceptual discrimination, arithmetic ability, visuomotor tracking, psychomotor skills, perception of task difficulty, and balance.

Is it possible to drink too much water?

Consuming excessive amounts of water can cause a condition known as hyponatremia, in which sodium levels in the blood drop too low due to dilution. Symptoms include nausea, poor balance and even organ failure. However, unless you’re an endurance athlete, hyponatremia is not really something you need to be concerned about.

The golden rule

The human body has an excellent method of preventing dehydration: thirst. Therefore, the best way to ensure adequate hydration is to listen to what your body is telling you, and never force yourself to drink more to achieve a pre-determined level. Drink when you are thirsty. Drink more water than any other beverage. Your body will thank you for it.


  • Armstrong, L. E., Ganio, M. S., Casa, D. J., Lee, E. C., McDermott, B. P., Klau, J. F., Jimenez, L., Le Bellego, L, and Chevillotte, E. (2011) Mild Dehydration Affects Mood in Healthy Young Women. The Journal of Nutrition, 10(3945).
  • Ganio, M. S., Armstrong, L. E., Casa, D. J., McDermott, B. P. (2011) Mild dehydration impairs cognitive performance and mood of men. British Journal of Nutrition, 106(10), 1535-1543.
  • Lieberman, H. R. (2007) Hydration and Cognition: A Critical Review and Recommendations for Future Research. Journal of the American College of Nutrition, 26(5), 555S-561S.
  • McKinney, J. L., Eberman, L. E., Cleary, M. A., Lopez, R. (2005) Effects of dehydration on balance as measured by the balance error scoring system. Southeast Athletic Trainers’ 30th Annual Member’s Meeting and Clinical Symposium, Atlanta, GA. March 2005.
  • Nutrient Reference Values for Australia and New Zealand: Water (2005) Australian Government: National Health and Medical Research Council.
  • Popkin, B. M., D’Anci, K. E. and Rosenberg, I. H. (2010) Water, hydration and health. Nutrition Reviews, 68(8), 439-458.
  • Smith, M. F., Newell, A. J., and Baker, M. R. (2012) Effect of Acute Mild Dehydration on Cognitive-Motor Performance in Golf. Journal of Strength and Conditioning Research, 26(11), 3075-3080.

InterDynamics News

Conferences and presentations

ISPO Conference (21-22 June 2017)

Rotterdam, The Netherlands

The ISPO (International Standard for Maritime Pilot Organizations) is a standard of best practice for pilots and pilot organizations, improving safety and quality. Providing self-regulation and transparency in pilotage standards to all port related stakeholders. This year, the annual ISPO conference was held in Rotterdam.

InterDynamics’ staff gave a presentation on ‘Implementing a Fatigue Risk Management System’ at the conference.

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: How much water do we really need to drink?

Seeker, 4 December 2013

Does the saying that you need eight glasses of water a day actually hold water? Trace looks at how much H2O you really need to drink to keep your body in prime shape.

Article: Brain’s biological clock stimulates thirst before sleep

Science Daily, 28 September 2016

The brain’s biological clock stimulates thirst in the hours before sleep, according to a study. Scientists have known that rodents show a surge in water intake during the last two hours before sleep. The study now reveals that this behavior is not motivated by any physiological reason, such as dehydration. So if they don’t need to drink water, why do they?

Welcome to Focus on Fatigue,

How many of us, when we get into bed at night, turn off the light and go straight to sleep? Probably not that many. Instead, we often take out our phone or tablet to check email, surf the internet, play a game or read a book. An hour or two later we plug our device in to charge on the bedside table and lie down ready to go to sleep. But will we go to sleep as quickly, or sleep as soundly, after staring at a screen right before closing our eyes? That’s the question we’ll be attempting to answer in this month’s Focus on Fatigue.

The FRMS Team



InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 2 8404 0400 Ext 23

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 Blue Light Blues

It has long been known that our bodies use light to help keep our circadian rhythm in check. The setting of the sun triggers a host of changes in our brains that make us feel sleepy. Then, as dawn lightens the sky, this process is reversed and our brains encourage us to wake up. Then the electric lightbulb was invented. Suddenly, we were bathed in light at all hours of the day and night. We managed to adapt to these changes, with most people still able to achieve adequate sleep each night, even if they did keep the lights on until well after dark. However, the introduction of electronic devices, such as phones and tablets, have thrown a whole new spanner in the works.

Why are electronic devices such a problem for sleep?

Most of the light that illuminates our days and nights is white light. The light produced by the sun is made up of all the colours on the spectrum mixed together, which makes white light. Also, while the lightbulbs we use in our standard light fittings can come in a whole range of colours (such as extra warm or cool), they are essentially all white light.

The light emitted by our electronic devices is different – it’s blue-enriched light. We might not be able to perceive the difference, but that doesn’t stop our brains from reacting differently. Blue-enriched light has been found to reset the timing of the circadian rhythm, suppress melatonin (the hormone that makes us feel sleepy), and elevate brain activation. All of which, reduce the likelihood of us falling asleep.

During the day, there are benefits to the presence of blue-enriched light in our lives. Exposure to blue-enriched light can improve subjective measures of alertness, positive mood, performance, and concentration. It can also reduce daytime sleepiness.

At night, however, exposure to blue-enriched light can lead to a number of negative consequences, such as:

  • reduced evening sleepiness,
  • increased sleep latency (it takes longer to fall asleep),
  • reduced slow-wave activity during NREM sleep,
  • reduced REM sleep, and
  • reduced next morning alertness (even when sleep duration is the same).

Some of the research also suggests that blue-enriched light exposure could lead to an increased risk of delayed sleep-phase disorder, sleep onset insomnia, and chronic sleep deficiency.

What can we do about it?

Several strategies have been developed to help reduce the effects of blue-enriched light on sleep, such as:

  • Don’t use any electronic devices without an hour of bedtime.
  • Those who enjoy reading a book before sleep should read a paper book or use an e-reader that is not backlit, such as some Kindles (if you don’t need your bedside light on to read it, it’s backlit).
  • It is possible to purchase glasses with orange-tinted lenses which reduce exposure to blue-enriched light. These glasses are mass produced, easily available and inexpensive.
  • Many devices have a night mode, which reduces the use of blue-enriched light.
  • A variety of software is available that can apply a mask or filter to the device itself to reduce blue-enriched light emissions.
  • Getting plenty of bright, natural light during the day has, in a recent study, been found to reduce the effects of exposure to blue-enriched light at night.

Can blue-enriched light be used to keep workers alert on night shifts?

It would be logical to assume, given the alerting and performance benefits of blue-enriched light, that exposure to it would be a great way for night shift workers to get through the tougher hours of their shift. Unfortunately, it has been found that chronic, inappropriately timed exposure to this kind of light can lead to circadian misalignment and eventually to sleep problems, depression and possibly even cardiovascular disease.

It’s not just about the light

Some sleep experts have pointed out that blue-enriched light is not the only reason that using electronic devices at night can have a negative effect on sleep. Activities such as playing games, checking email and surfing the internet, also act as stimulants, keeping our brains awake and active. So, if you must use an electronic device before going to sleep at night, use one of the blue-enriched light reduction strategies mentioned above and use the time to read a relaxing book. You’ll sleep better for it.


  • Burkhart, K. and Phelps, J. R. (2009) Amber lenses to block blue light and improve sleep: A randomized trial. Chronobiology International, 26(8), 1602-1612.
  • Cajochen, C., Frey, S., Anders, D., Spati, J., Bues, M., Pross, A., Mager, R., Wirz-Justice, A. and Stefani, O. (2011) Evening exposure to a light-emitting diodes (LED)-backlit computer screen affects circadian physiology and cognitive performance. Journal of Applied Physiology, 110, 1432-1438.
  • Chang, A.-M., Aeschbach, D., Duffy, J. F. and Czeisler, C. A. (2015) Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. PNAS, 112(4), 1232-1237.
  • Gringras, P., Meddleton, B., Skene, D. J. and Revell, V. L. (2015) Bigger, brighter, bluer-better? Current light-emitting devices – adverse sleep properties and preventative strategies. Frontiers in public health, 3, 233.
  • Rangtell, F. H., Ekstrand, E., Rapp, L., Lagermalm, A., Liethof, L., Bucaro, M. O., Lingfors, D., Broman, J.-E., Schioth, H. B. and Benedict, C. (2016) Two hours of evening reading on a self-luminous tablet vs. reading a physical book does not alter sleep after daytime bright light exposure. Sleep Medicine, 23, 111-118.
  • Viola, A. U., James, L. M., Schlangen, L. J. M. and Dijk, D.-J. (2008) Blue-enriched white light in the workplace improves self-reported alertness, performance and sleep quality. Scandinavian Journal of Work and Environmental Health, 34(4), 297-306.

InterDynamics News

Conferences and presentations

USA Rail Crew Management & Timekeeping Conference (23-26 April 2017)

St Augustine, Florida, USA

Hosted by CSX Transportation, this conference is an annual event and features discussions around crew management and timekeeping issues that confront all the operators, including fatigue and FRMS. Staff from InterDynamics attended the conference, which also included representatives from Union Pacific Railroad, BNSF, Norfolk Southern, Canada National, Canadian Pacific, Kansas City Southern and AMTRAK.

ISPO Conference (21-22 June 2017)

Rotterdam, The Netherlands

The ISPO (International Standard for Maritime Pilot Organizations) is a standard of best practice for pilots and pilot organizations, improving safety and quality. Providing self-regulation and transparency in pilotage standards to all port related stakeholders. This year, the annual ISPO conference was held in Rotterdam.

InterDynamics’ staff gave a presentation on ‘Implementing a Fatigue Risk Management System’ at the conference.

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: Blue light hazardous to sleep, but helpful to daytime functioning?

Dr Michael J. Breus, HuffPost (24 March 2014)

A new study further examines the stimulating effects of blue wavelength light, focusing on the effects of daytime exposure to the short-wavelength light. They also compared the daytime effects of blue light exposure to the effects of evening exposure to the same degree of light.

Video: How smartphones keep you awake

Reactions, YouTube (19 May 2014)

Your smartphone addiction isn’t helping you sleep. In fact, an obscure chemical reaction may be keeping you awake. The latest Reactions video looks at the process that connects your late-night texts to your lack of sleep.

Welcome to Focus on Fatigue.

Winter is coming down here in the southern hemisphere. That means the days are growing shorter and the nights are noticeably cooler. There is nothing better than snuggling in the warmth of thick blankets when the weather cools, and this can often lead to a few extra hours of sleep than we would normally get. This month, in Focus on Fatigue, we will look at the benefits extra sleep can bring and how we can use regular doses of additional sleep in a productive way.

The FRMS Team

InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 2 8404 0400 Ext 23

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).

Feature Articles

Sleeping Ahead of Schedule

Sometimes we know we aren’t going to get enough sleep in the days ahead. This may be due to shift work, or because we have a work project with a tough deadline. Maybe we’re just really keen to watch the new season of our favourite Netflix show from end to end without stopping. Whatever the reason, if we know that a period of sleep deprivation is coming up, is there anything we can do to prepare for the fatigue that lies ahead? The research says, “Yes! It can be done.” But it’s not as simple as having a single good sleep-in before the big event.

Extra sleep goes a long way

A group of college students were given the opportunity to get as much sleep as possible. They were tested on a variety of measures before the extra sleep began, half way through the study, and again at the end. The researchers found the students who did achieve extra sleep showed substantial improvements in a number of areas, including vigilance and mood. Those who achieved the most sleep showed exceptional improvements.

Does the extra sleep help when your sleep is then restricted?

Another group of researchers wanted to know if sleep history made a difference to the speed at which performance and alertness degraded during a week of chronic sleep restriction, and the subsequent recovery period. Their participants were split into two groups: the extension group (who were in bed for 10 hours each night in the week leading up to the sleep restriction) and the habitual group (who went to bed for whatever amount of time was usual for them).

During the sleep restriction phase, both groups were only allowed to sleep for three hours per night for a week. Then they underwent a recovery phase during which they were able to sleep for 8 hours each night.

The researchers found the extra sleep improved resilience on measures of performance and alertness during the sleep restriction phase, and it also facilitated recovery thereafter. So, the participants who had extra sleep before the restriction still didn’t perform as well as they did when they were well-rested, but they performed much better than those who hadn’t had extra sleep in the lead-up to the sleep restriction, and they recovered from the sleep restriction faster.

What if you’re not going to get any sleep at all?

Arnal and colleagues went one step further. They asked if extra sleep, banked in advance, still helps in the case of total sleep deprivation. Again they had one group of extended sleepers and one of habitual sleepers. However, this time the study was run twice so that each individual could participant in each of the two groups. Also, these participants began with a control week in which they were in bed for 8 hours per night in an attempt to wipe out any sleep debt they might have had before starting the study.

The researchers found that the participants who had extended sleep had improved sustained attention during total sleep deprivation, reduced lapses in vigilance and fewer microsleeps. The extra sleep also helped them recover faster.

One interesting finding was there was no difference in the subjective sleepiness of the participants. Everyone felt just as sleepy during the deprivation phase, whether they’d had extra sleep or not. That subjective sleepiness did not stop extended sleepers from performing better.

The good news

  • If you are preparing for a period of partial or total sleep deprivation, or just a day where better attention and alertness will be beneficial, getting extra sleep ahead of time will help.
  • Banking sleep can provide limited protection against some of the performance and mood degradation inherent in sleep deprivation.

The bad news

  • In each of these studies, the participants were spending up to 10 hours in bed each night for 6 or 7 nights. One or two nights of extra sleep will not necessarily have any protective benefit.
  • Banking sleep will not stop your performance from decreasing during sleep deprivation, it will only slow the rate of decrease.
  • Sleep-ins on the weekend will not provide protection from fatigue during the week. The protective factors discussed in these studies were only found after a full week of extended sleep, even when attempts were made to eliminate any prior sleep debt.

What can we take away from this research?

Banking sleep is a useful tool to have in our fatigue risk management toolbox. However, realising the benefits of extra sleep requires lengthy planning and preparation. This makes it more of a ‘special occasion’ tool, rather than a ‘daily-use’ tool. In the event you do manage to use banked sleep to assist in preventing fatigue, do enjoy the extra sleep. It’s possibly the most well-rested you’ll ever get.


  • Arnal, P. J., Sauvet, F., Leger, D., van Beers, P., Bayon, V., Gougard, C., Rabat, A., Millet, G. Y., and Chennaoui, M. (2015) Benefits of sleep extension on sustained attention and sleep pressure before and during total sleep deprivation and recovery. Sleep, 38(12), 1935-1943.
  • Kamdar, B. B., Kaplan, K. A., Kezirian, E. J. and Dement, W. C. (2004) The impact of extended sleep on daytime alertness, vigilance, and mood. The impact of extended sleep on daytime alertness, vigilance, and mood. Sleep Medicine, 5, 441–8.
  • Rupp, T. L., Wesensten, N. J., Bliese, P. D. and Balkin, T. J. (2009) Banking sleep: Realisation of benefits during subsequent sleep restriction and recovery. Sleep, 32(3), 311-321.

In the News

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

Article: Bank sleep to fight tiredness, research says

Dave Lee, BBC World Service (9 February 2010)

As anyone who has unwittingly drifted off at their desk will know – tiredness can really creep up on you when you least need it. But a new study is offering some good news: it claims to prove that we can bank sleep – and store it up in advance of a tiring event.

Article: Skimpy sleep followed by ‘catch up’ can hurt attention and creativity

Traci Pedersen, PsychCentral (25 April 2017)

Alternating between nights of very little sleep and long “catch up” attempts is linked to poor attention and creativity in young adults, particularly for those working on major projects, according to a new study at Baylor University.

Video: How to sleep longer

Howcast, YouTube (18 September 2013)

A short video with Priyanka S. Yadav (Pediatrics and Sleep Medicine Specialist) who provides simple tips for sleeping longer.





Welcome to Focus on Fatigue.

Here in Australia we are just starting to emerge from a long and very hot summer. If there’s one thing I don’t like to do when the temperature soars, it’s exercise. For those of you in the northern hemisphere, the thought of coming out of blanket hibernation to go for a run during the winter months may not be any more appealing. However, as we all know, regular exercise is one of the three fundamental cornerstones of good health (along with plenty of sleep and a healthy diet). And now that cooler (or warmer) weather is just around the corner, this is the perfect time to get started on a regular exercise routine.

This month in Focus on Fatigue we’ll look at the benefits of regular exercise on getting a good night’s sleep.

The FRMS Team



InterDynamics Pty Ltd
320 Adelaide Street Brisbane Qld 4000
Tel +61 2 8404 0400 Ext 23

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).

Feature Articles

Exercise and Sleep

We all know how important it is to get enough sleep. Unfortunately, achieving the rest we need is not always easy, especially when doing shift work. There are times when good sleep hygiene practices, such as having a dark room and a comfortable bed, are simply not enough. Thankfully, there are many habits we can instill in our waking lives that will support our sleep. One of these habits is, of course, wearing ourselves out. Yes, regular exercise is a great way to increase the chances of achieving a restful sleep when we slip beneath the covers.

In 2013, the National Sleep Foundation conducted a Sleep in America poll of 1000 people from across America. The poll found overwhelming support for their proposition that exercise is good for sleep. Those who identified themselves as ‘vigorous exercisers’ reported the best sleep. They also reported having no problem maintaining enthusiasm to get things done in the previous two weeks. However, even those who identified as ‘light exercisers’ reported significantly better quality of sleep than those who did no exercise at all.

Meanwhile, non-exercisers were significantly more likely to report poor health. They were also more likely to have trouble staying awake while driving, eating or engaging in social activities. They drank more coffee, took more medicated sleep aids, were excessively sleepy during the day, had lower moods, and were at greater risk for sleep apnoea.

The most important thing to remember here is that, while vigorous exercise was best, even light exercise was enough for participants to start experiencing benefits.

Once you’ve fallen asleep, regular exercise has been found to increase sleep length and can also have an impact on the quality of sleep.

These sorts of improvements have been found in a wide variety of groups, including people with insomnia, those with mild to moderate sleep apnoea, and in adolescents.

Can I exercise close to bedtime?

Many people believe they shouldn’t exercise too close to bedtime because it will interfere with their sleep. This is not surprising considering sleep tip lists all over the internet will tell you exercising in the hours before bedtime is a bad idea.

The research, however, has found that this is not necessarily true. The Sleep in America poll found no significant differences between the sleep quality of those who did even vigorous exercise within four hours of bed and those that exercised earlier. Another study wanted to test this hypothesis more specifically. It concluded “that vigorous late-night exercise does not disturb sleep quality.” Other research has had similar results.

Exercise does cause a whole host of reactions in the body, such as increasing hormone levels, blood flow to muscles, and body temperature. But according to sleep experts, it only takes an hour for these processes to return to normal levels. So, if you are going to exercise before going to sleep, do make sure to give yourself an hour to cool down.

How this all relates specifically to shift workers has yet to be seen. However, what we can take away from these research studies is this: If the only time you have available to devote to exercise is in the hours before you sleep, don’t feel that you have to refrain on the basis that the exercise will harm your sleep. This will not necessarily be the case.


  • Brand, S., Gerber, M., Beck, J., Hatzinger, M., Puhse, U. and Holsboer-Trachsler, E. (2010) High exercise levels are related to favourable sleep patterns and psychological functioning in adolescents: A comparison of athletes and controls. Journal of Adolescent Health, 46(2), 133-141.
  • Flausino, N. H., Da Silva Prado, J. M., de Queiroz, S. S., Tufik, S. and de Mello, M. T. (2011) Physical exercise performed before bedtime improves the sleep pattern of healthy young good sleepers. Psychophysiology, 49(2), 186-192.
  • 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.
  • Neil-Sztramko, S. E., Pahwa, M., Demers, P. A., and Gotay, C. C. (2014) Health-related interventions among night shift workers: A critical review of the literature. Scandinavian Journal of Work, Environment and Health, 40(6), 543-556.
  • Reid, K. J., Baron, K. G., Lu, B., Naylor, E., Wolfe, L. and Zee, P. C. (2010) Aerobic exercise improves self-reported sleep and quality of life in older adults with insomnia. Sleep Medicine, 11(9), 934-940.
  • Sengul, Y. S., Ozalevli, S., Oztura, I., Itil, O. and Baklan, B. (2011) The effect of exercise on obstructive sleep apnea: A randomized and controlled trial. Sleep Breath, 15, 49-56.

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: Does exercising before bed take a negative toll on sleep quality?

Chantal Da Silva, The Independent (2 February 2017)

‘The early bird gets the worm’ is a favourite adage among morning gym-goers, but what about those of us who prefer to live – and exercise – by night?

Article: How Exercise Makes You More Resilient to Mental Fatigue

Brad Stulberg, Science of Us (22 July 2016)

Life, as you may have heard, is not always so easy, and so it’s important to practice being comfortable with being uncomfortable. One of the most reliable ways to do that — as Science of Us reported last month — is by pushing yourself physically: People who undertake and endure exercise challenges tend to perform better in hard, yet ostensibly unrelated, areas of their lives, such as quitting smoking or remaining calm during final exams. The scientific theory underlying this phenomenon is called the “cross-stressor adaptation hypothesis.”

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!





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