As fatigue sets in, our ability to respond degrades. You know the feeling – you are reading something and realise that you have taken none of it in and have to go back and start again. It’s that ‘war-weary’ feeling of trying to mentally pick yourself up, dust yourself down and go again. The consequence of fatigue is that the degradation in the speed, accuracy and quality in how we respond means we are more likely to make mistakes. Just how serious is being tired at work?

A useful analogy is to think of fatigue in terms of alcohol consumption. The more you drink, the drunker you become. The more inebriated you are, the more unable you are to do the most basic of tasks. As for something as simple as driving – forget it – if you are drunk, you are a serious danger to yourself and other road users. The same is true for fatigue. Fatigue is a spectrum from, on the one hand being alert and awake and, on the other needing to fall asleep. Persevering when you really need to get some rest is to ramp up the risk of taking a poor decision or worse, having an accident. Research has demonstrated that having a period of sustained sleep deprivation is the equivalent of being drunk.

Universally, turning up at the office while intoxicated is unacceptable, yet think for a moment how many people turn up for work tired. Parents of young children, people coming to work after a long haul flight and staff who have had a late night with friends. This is aside from the travails of shift work. We really should treat fatigue as a serious issue.

Pilots, drivers of commercial vehicles, air traffic controllers all have their hours closely monitored to ensure they are not overtired at work – so why not for all employees? Equally sound judgement and decision-making ability are required by the senior executive making a major strategy or investment decision; or by the manager who is interviewing candidates for a new position on their team. In the absence of legislation, what can we do to improve our awareness and management of fatigue?

The challenge is how to determine when our fatigue levels are such that we would be better off taking a rest than to continue working. Relying on the person who is tired to make this decision is problematic for two reasons. Firstly, we are not very good at judging risk. By way of illustration, it is well understood that exercise and a healthy diet significantly reduce the risk of ill health, but many people eat too much of the wrong things and exercise too little. It’s easy to see why. The fish and chip supper on a Friday night didn’t kill you last week, or the week before, or the week before that, so the chances are it won’t kill you this week. But you have no real idea whether you are an inch or a million miles away from a heart attack or how much each mouthful takes you closer to the risk. Similarly, we are all happy to drive (or be driven) on roads. If I told you that in the UK, there are 31.9 deaths per million vehicles does that help you understand the risk of losing your life whilst driving? Probably not. The data is relatively meaningless.

For people to make a decision about their fitness for work based on risk of incident, we would need to have a commonly accepted understanding of what is an acceptable risk. “I’ll be alright,” is not enough justification for working when overtired. This is because people have different appetites for risk. Free climbers, who choose to scale massive rock faces without any form of protection in the event of a slip or a fall have a different approach to risk than the person who insists on holding a handrail when going up or down a staircase. Secondly, there is the problem of our perception of how tired we really are. I am sure you can recall having a conversation with someone who absolutely believed they were fine but quite clearly were not. You probably noticed changes in their behaviour, simple mistakes that were made or perhaps dropping things. This told you they were far from OK and would benefit from some ‘time out’. People can push themselves to extraordinary levels of performance despite being incredibly tired, but that does not mean they should. Knowing when to stop sometimes requires outside intervention to help us make the decision. Equally, people may be capable of a lot more than they think, but what is lacking is not so much rest but motivation. Much evidence exists that fatigue can in part be overcome through the judicious use of a suitable reward.

We need a three-pronged attack to the problem. Firstly, we need to raise the awareness that being fit for work means being properly rested. This means having a sense of what this means in practice. Secondly, individuals need to take responsibility for their own condition and recognise in themselves when they are tired and or be open to others telling them that they are tired. Thirdly, we need to legitimise the value of time-out. Recreation is just that, re-creation. The good news is that sometimes when we are mentally fatigued, a short rest can be sufficient to get us back to an acceptable level of effectiveness. This need only be a ten minute nap for a restorative benefit to be realised. For this to be truly effective, we need to keep the focus on the outcomes people deliver rather than whether they are seen to be working or sleeping.