There are many reasons behind the numbers; a disregard for the ‘value’ of sleep, increased stimulation caused by our ‘always-on’ lives in the digital age, and changes in the modern lifestyle and habits of people in general. Yet, irrespective of the reasons behind this increasing lack of sleep, it is now obvious that many of us do not get enough rest and recovery from our day.
With a very simple calculation, it could be argued that for working-age humans, on average, one third of the day is spent at the workplace, one third in leisure-time activities and one third sleeping. But life, however, is not nearly this inflexible and structured for most of us, and the listed activities often overlap each other in a number of ways. Additionally, several studies have indicated that the time we allocate for sleep has decreased over recent decades, although our physiology has not adapted to overcome this.
At work, fatigue, often resulting from sleep deprivation and/or poor quality of sleep, is a source of risk. Lack of sleep can influence both the individual worker’s health, safety and wellbeing, as well as also jeopardise the company’s operations, as reliability decreases and the number of errors and mistakes increase, for example.
Fatigue as a part of human performance
Human factors could arguably be viewed as a synonym for ergonomics, which combine the physical, cognitive and organisational factors that influence human performance. Human factors refer to all the technical, workplace and individual characteristics, alongside organisational matters, which have an impact on our behaviour and performance. These sciences, in effect, study human performance and the factors that allow us to succeed, or indeed fail, in various situations.
In recent decades, it has become increasingly clear that failures in human performance are behind many accidents. In popular contexts, human error has often been named as the cause of an accident, rather than a technical malfunction or system breakdown. Human error has also been commonly perceived as something that ‘just happened’ and is thus difficult to predict or control. Within this context, fatigue is a good example of a factor which can contribute towards many kinds of incidents occurring.
Fatigue itself does not cause accidents, as such, but it can have a remarkable influence on the way we perform. Together with task complexity and/or distracting factors in the operating conditions (such as noise pollution), fatigue can be a major contributing factor with regards to igniting a chain of events that will eventually lead to an accident.
According to Sawatzky (2017), there are four main ways in which fatigue impairs performance:
- Alertness – It is normal that our alertness levels vary naturally throughout the day, and often we do not even notice it. They simply happen, whether we feel tired or not. However, fatigue makes it even more difficult for people to remain alert, recognise or notice abnormalities, as well as impairs their reaction time to any changes.
- Emotional stability – In critical situations, fatigue often impairs our ability to remain emotionally calm and stable. Also, aggressive behaviour and depression may become more common when we feel tired and/or are sleep deprived.
- Mental ability – Fatigue, and sleep deprivation in general, impairs our ability to think, remember and communicate clearly.
- Physical ability – Fatigue leads to a lowering of reaction times and coordination. Micro-sleep, which can be defined as a sudden, uncontrollable and very temporary episode of sleep, lasting from fractions of a second up to around 30 seconds, also belongs to this group: microsleep poses a major risk for health and safety, for example in traffic or in the work environment.