20120730 - Sleep management for commercial pilots

[<Normal page] [O'DONNELL Louise (20112). Sleep management for commercial pilots. Aeroscience (ISSN 2324-4399), 2012, pages 42-44.]

Sleep management for commercial pilots

We are all aware that sleep deprivation has the potential to affect flight safety with signs of impaired performance and reduced alertness, tiredness, the need to sleep, or just plain exhaustion. This lack of sleep is responsible for a decline in performance, ultimately resulting in cases of cumulative fatigue through sleep loss. Significantly, the effects of sleep loss will vary depending on the task, with the more complex tasks suffering rather than the simpler ones. So how can we effectively manage tiredness to ensure it does not cross over the line resulting in fatigue?

As more pilots than ever recognise fatigue as part of their job, it becomes increasingly important to reinforce the benefits of sleep and the necessity to adjust ones lifestyle to prevent ill health as a shift worker. Effective sleep management is a major tool in helping combat the effects of fatigue by assisting the body clock in coping with the demands of shift work, eating, drinking and digestion. It also allows the body’s physical functions to rest and restore various parts of the central nervous system. Let us not forget that fatigue is there to protect us from overwork, as a kind of defence mechanism intended to prevent us from exerting ourselves too far and causing damage. Regardless of the scale of fatigue or tiredness experienced, sufficient restorative rest and sleep will always return you to full fitness.

We have an internal clock based on a twenty-four hour cycle which governs our life. These circadian rhythms are linked to the light/dark cycle (used as external cue), and regulate our eating and sleeping, as well as other biological functions. Consequently, when it is dark we sleep, and when it is light we are awake. However, shift workers continually struggle with this biological rhythm in an effort to adapt it to fit schedules and lifestyle. The graph of the circadian rhythm identifies 5am as the hardest time to stay awake, as it is the time when the body temperature and sleep/wake cycle is at its lowest point.

(Image embedded from circadian.org on 18 August 2011)

On the other hand, there is the homeostatic rhythm which runs in tandem with the first, focusing on the length of continuous wakefulness. Put simply, this is a sleep reservoir, easily described as a credit and deficit point system. Each hour slept earns 2 points credit (maximum 16 points) with 1 point deducted for every hour awake. Most importantly, it is not possible to store these sleep credits. Once the 16 points have been depleted the body is generally ready for sleep. This is why a short afternoon power nap is not always beneficial, because essentially you are replenishing your sleep reservoir and consequently extending your wakefulness.

In general, individuals require varying quantities of sleep, but how many hours sleep do you need each night to feel refreshed and ready for the next day? If you don’t know, a good start is to set yourself a trial, identifying how much restorative sleep you actually require. This can be accomplished when you don’t need an alarm call and have no time critical commitments. Retire to bed reasonably early and, upon waking, estimate how many hours sleep you have actually achieved. By performing this experiment for a minimum of three nights, not necessarily consecutive, it should identify your average sleep requirement. Having now worked out how many hours sleep you need, this essentially becomes your 'fuel calculation'.

After discovering how much sleep is required, how many pilots knowingly sign on for duty with less than minimum 'sleep fuel' in the tanks? When put into context, does it not seem ridiculous that what occurs all too often is a situation where pilots are carrying insufficient 'fuel' (ie, sleep) for their daily sectors? Is it any wonder pilots feel fatigued? In exactly the same way that a lack of fuel will have an aircraft falling out of the sky, cumulative fatigue caused predominately through lack of sleep will 'ground' you. The simple solution is, of course, more sleep, but with life now one big planning exercise of meeting up with friends, collecting children from school, taking the car to the garage, and the cat to the vet, we have become increasingly time poor. Although we plan our time effectively ensuring we arrive at work to sign on and brief on routes, fuel, alternates, breaks, paperwork, boarding, etc, we essentially miss out the most important part of the planning, that of sleep. Frequently, we accept whatever time is left over at the end of the day for slumber, having stayed up to watch a television programme, read a book, or, worse, having been rostered a late to early duty. The regulation 10 hour minimum rest makes sufficient sleep even harder to achieve, taking into account the commute, wind down, or an overnight duty in a strange bed, different noises, and even fleas!

As a result of our newfound knowledge on how many hours sleep we require, what could we be doing? Well for the majority it will be a whole life change, but how many are prepared to do that? By this, I mean quite simply, planning daily activities after the sleep requirement has been deducted. Therein lies the problem, in that after calculating this we quickly realise it can mean walking in the door from a late duty, teeth out, slippers on and waving goodbye to the family, as you head straight to bed in order to achieve sufficient sleep for an early morning sign on. Forget that you have not been home all day, seen the family since breakfast, opened any mail, or read the paper.

Subsequently, these idealisms may appear impractical as we recognise there are many competing needs for sleep from managing lifestyles, family, and responsibilities, to commuting and unforeseen events. Importantly, it should also be recognised that just because a rest period has been set aside, sleep cannot always be guaranteed. Ultimately, what is being suggested is that perhaps it is more prudent to record the late movie, and not spend half an hour surfing the corridors of eBay for some obscure item prior to bedtime. Whilst pilots appear reasonably disciplined individuals, this does not seem to extend to effective management of sleep requirements. Although a rigid approach to planning sleep is not recommended, what is nonetheless needed is just a better appreciation and adaptation of lifestyle to this chosen field of work as a shift worker. It is not rocket science to work out that if you need eight hours sleep but frequently achieve seven, this will eventually result in cumulative fatigue. Regardless, both pilot and airline have an equal responsibility in managing measures to combat the effects of fatigue, collaboratively reducing the probabilities of its effects on flight safety.

1. O'DONNELL Louise J (2008). Managing fatigue - a way forward, the practical solution. Air Nelson Safety Link, 2008 (October), pages 16-17.
+++ Footnotes +++
2. The original and unabridged version of this article was published in the thirteenth edition of the Air Nelson Safety Link Magazine, supporting an article by Simon Bennett on managing fatigue. Adapted and reproduced with permission.


Louise O'DONNELL (2011). Air Nelson, New Zealand. Louise ODonnellLouise ODonnell


Nicholas ASHLEY (2011). School of Aviation, Massey University, New Zealand (NickAshleyNickAshley).
Jose D PEREZGONZALEZ (2011). School of Aviation, Massey University, New Zealand (JDPerezgonzalezJDPerezgonzalez).

Want to know more?

Aviation Knowledge - Circadian Rhythms
This AviationKnowledge page expands on the effects of circardian rhythms on the body and suggests steps on counteracting its effects.
Aviation Knowledge - Pilot Fatigue
This AviationKnowledge page offers further information on causes of pilot fatigue, its effects and management strategies.
Book - Fatigue in aviation
This book provides a comprehensive understanding of the concept of fatigue through a practical and easily understandable yet authorative approach. You can find the books as, CALDWELL John A & Lynn CALDWELL (2003). Fatigue in aviation: a guide to staying awake at the stick. Ashgate (England, UK), 2003.

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