Wake up to fatigue

We all know that sleep is important for staying healthy – and that we need enough of it to function properly. But how much is enough? And what other factors increase the risk of fatigue?
a small fishing vessel that is listing slightly in moderate ocean swells that appears to have grounded.

As well as exploring the meaning, causes and signs of fatigue, we'll look at the dangers of building up ‘sleep debt’ and the only remedy for it.


What is fatigue?

Fatigue is about more than feeling tired. The International Maritime Organisation (IMO) defines seafarer fatigue as:

“A reduction in physical and or mental capability as the result of physical, mental, or emotional exertion which may impair nearly all physical abilities including: Strength, speed, reaction time, coordination, decision making, or balance.”

Fatigue happens when you:

  • don't get enough sleep
  • work when your body is programmed to sleep
  • can't sleep when you have the chance
  • have poor quality sleep.
  • Most of us need 7-9 hours of sleep a night. Less than 5 hours is dangerous. Combine this with several nights of not enough sleep, and the danger escalates. So when you lose sleep, it's important to make up for it with extra sleep to prevent fatigue from building up.


What causes fatigue?

Many things can lead to fatigue, but in commercial fishing it's mostly caused by long or irregular work hours, disrupted sleep, tough physical work, and stress. Other factors that can increase the risk include:

  • work/rest patterns that don't give you enough opportunity for recovery sleep
  • needing to be awake for a long time (more than 16 hours)
  • working during the part of the day when your capacity for performance is low, and your body's urge for sleep is high.

Then there are other factors that can make fatigue worse such as:

  • boring or repetitive work e.g. watchkeeping at night
  • mentally demanding tasks e.g. controlling a fishing vessel when looking for and catching fish
  • being too cold or too hot
  • vibration
  • noise
  • a ship's motion
  • hydration and nutrition – what you eat and when
  • caffeine, alcohol and drugs.


What are the signs?

The signs of fatigue can vary from person to person, but be aware of these common signs:

  • tunnel vision (overly focused on one task)
  • poor concentration
  • mood swings
  • easily distracted
  • forgetful
  • more irritable than usual
  • slow responses
  • taking unusual risks
  • making mistakes
  • poor judgement
  • clumsiness.

If you experience two or more of these signs, make sure you tell someone. Similarly, if someone else tells you they're experiencing any of these signs, make sure you listen – and do something about it.

“Fatigue is a big issue. The job involves fatigue. There are very few times when you don't have to stay awake. You need enough crew to run a watch system.” – Alec (skipper)


What is ‘sleep debt’?

‘Sleep debt’ is the term used to describe the result of not getting enough sleep night after night. When this happens, your performance becomes increasingly unreliable and you find yourself slipping in and out of ‘microsleeps’ (nodding off). In this state, you're not fully aware of what's going on around you and you struggle to do your job properly.

The dangers of sleep debt

  • Going without the sleep you need sleep is called sleep debt. As you go into more and more sleep debt, it becomes harder to judge your own abilities. You might feel alert, not at all sleepy – and perfectly fit to work. The danger is, your performance won't be up to scratch
  • The less sleep you have every 24 hours, the faster you go downhill.
  • Recovery from total sleep deprivation (24 hours without any sleep) usually takes 1–2 nights of uninterrupted sleep. Recovery from inadequate sleep night after night, on the other hand, can take days or sometimes weeks.


What's the remedy?

There is only one remedy for overcoming fatigue that builds up over a few nights – and that is sleep!

Given that 70-80% of maritime accidents are thought to be caused by human error, and the results of our recent survey suggest fatigue plays a role in causing such errors, it's crucial that you do what you can to fight off fatigue. This means getting enough sleep.

“Make sure that when you get downtime, you make good use of it. Take your sleep! Look after yourself well.” – Rory

Download our poster to help your crew wake up to fatigue [PDF: 497kB, 1 page]


Fatigue facts

  • Fatigue is about more than feeling tired.
  • Sleep debt is a result of not getting enough sleep night after night.
  • The only remedy for sleep debt is sleep.