We had the chance recently to talk to one of the world-leading experts on sleep, stress and fatigue; Professor Torbjörn Åkerstedt from Stockholm University and the Karolinska Institute. We took the opportunity to ask him a few questions relating to the differences between fatigue levels for pilots versus cabin crew.
Professor, cabin crew have a work situation which, compared to pilots, involves much more physical work with serving food, attending to passengers and so on. What is the scientific position on how labour, movement and communication etc. reflects upon cognitive fatigue; sleepiness, reaction times and decision making, compared to mostly sitting down with few opportunities to move?
- The brain is geared to deal with variation, evaluating and reacting to changes in our environment. When we are occupied in this way, fatigue/sleepiness is generally suppressed - but it will surface later on. More intense workload situations, even stressful ones, will typically not manifest in sleepiness until we relax or later during the stress exposure. Monotonous work, such as monitoring tasks, are also not agreeing well with our brain but a rest break will normally help and restore much of our cognitive capability. Both over- and under stimulation can thus lead into elevated levels of sleepiness, but in the former case firstly after settling down. Hard labour or stressful work will delay the onset of sleepiness, but looking at the overall sleep need for people being less or more physically active, there is little evidence that points to any real differences.
Interesting, what about the effects of light conditions? On a long-haul flight for example, the cabin crew could work in a quite dark environment while passengers are asleep, while the pilots could be exposed to full sunlight. What does the science tell us about the effects of that difference on cognitive fatigue?
- Light is very central to us as human beings and, especially bright light, has a direct alerting effect. The Thalamus in our brain, centrally located and responsible for relaying motor and sensory signals, spins up in activity when we are exposed to light. However, working in dark conditions is related to your previous question - we easily become under-stimulated as the brain lacks the variation and changes in the environment to occupy itself with.
Thank you. Finally, let’s say that cabin crew are predominantly younger females, while pilots are generally somewhat older males. On average, would age and gender create a difference in the cognitive fatigue levels or performance between the two groups?
- In general, higher age is associated with lower levels of experienced sleepiness and also an increased resilience to sleep debt. Higher age, but perhaps also longer experience and a different social situation, also leads to coping with stressful work somewhat better. There is also an increased tendency to become a 'morning-person' and more frequently use or need napping. The difference between men and women however is mostly absent - they tend to experience very similar levels of sleepiness.
Thank you, great talking to you!
Many of the scientific publications by Professor Åkerstedt can be found through this page.
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