8 myths about sleep and fatigue

Fatigue is a strong Performance Influencing Factor, and can lead to poor performance on tasks which require attention, decision-making or high levels of skill. There’s a huge amount of material available on the subject of fatigue, working hours/patterns and sleep. I don’t intend to summarise this material here, but simply draw attention to a few common misconceptions.

MYTH 1: I can tell when I’m going to fall asleep

  • Very unlikely. Who can remember the exact moment that they fell asleep last night? The more tired that you become, the less able you are to make a good judgement about your ability to remain awake, or recognise that your performance is deteriorating. We are all bad judges of how fatigued we actually are.

MYTH 2: I’m really experienced. I can fight off any feelings of fatigue

  • You cannot simply “decide” to feel less tired. Although intense concentration may help for a short period, fatigue cannot be overcome by willpower, experience or motivation. The only remedy for fatigue is sleep.

MYTH 3: I only need five or six hours of sleep a night

  • Very few people can manage on this amount of sleep without being seriously affected. Most people require 7 to 9 hours of sleep per night.

MYTH 4: If I sleep a lot now, I won’t need to sleep much later

  • Sleep is not like money. You can’t save it up and you can’t borrow it.

MYTH 5: Fatigue can be managed by addressing working time arrangements

  • Fatigue isn’t just about managing working time. Fatigue can also be made worse by workplace conditions. High-pressure demands, poor lighting, constant noise, heat, cold, vibration and even poor weather can make you feel more tired.

MYTH 6: Daytime sleep is just as good as night-time sleep

  • Shift workers who have to sleep during the day get lower-quality sleep, and less of it.

MYTH 7: You can’t tell if someone is fatigued

  • There are symptoms that may indicate a worker is fatigued, such as short term memory problems, an inability to concentrate, impaired decision-making, slow reflexes and withdrawal from interpersonal communication.

MYTH 8: Our bodies get used to working shifts

  • If you are working when you would normally be sleeping, or sleeping when you would normally be awake, you will be fighting against your natural instincts to work during the day and sleep at night.

I’ve created a briefing note below containing these 8 myths that you can download. You may wish to post this document on a notice board, discuss it in a safety meeting, or use it as part of a workshop on fatigue management.

For more background on fatigue, its causes, the warning signs and how to manage it, see the topic page – www.humanfactors101.com/topics/fatigue


There’s no point in having a competent workforce if they are too tired to work safely!  Fatigue needs to be actively managed, just like any other hazard.

Eight myths about fatigue and sleep
Eight myths about fatigue and sleep

Heading picture credit – http://www.flickr.com/photos/e3000/6550254039

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