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The long-term health effects of fatigue: impacts on mental health

by Emma Chisholm Programme Director

We know the immediate effects of fatigue have the potential to compromise flight safety, but what effect can chronic fatigue have on your mental and physical well-being in the long term? In this two-part series during Stress Awareness month, BALPA’s Programme Director and part of our ‘Focus on Fatigue’ team, Emma Chisholm, explores this vital issue

To date, much of our focus has been on the safety impact of fatigued pilots. But what about the impact on pilots themselves? The physical effects of sleep deprivation are easier to talk about but what about the impact on longer-term mental health?

BALPA is aware of cases of long term sickness related to fatigue and ‘burnout’ across the Association, but also an increased demand for part-time work. These are worrying indicators that a pilot’s workload may not be sustainable and the next phase in our ‘Focus on Fatigue’ campaign will look at these long-term health implications for pilots.

Shift and night work are medically recognised risk factors for health and well-being as they interfere with four main spheres of life:

1. Basic biological functions – Circadian rhythms are disturbed, beginning with the sleep/wake cycle

2. Performance and work ability – Due to fluctuations in performance and efficiency over 24-hour time period.

3. Social relations – Difficulties maintaining normal relationships with family and friends

4. Health – In the short term this can be manifested by sleeping disturbances, anxiety, irritability and hormonal disturbances. And in the longer term this may result in more severe cardiovascular, gastrointestinal and neuropsychological disorders.

The impacts of long-term sleep deprivation on mental health

The pilot lifestyle of shift work, night work and time zone changes, combined with more demanding, yet EU regulation-permissible rosters, are not conducive to regular and predictable sleeping patterns. So what can this mean for mental health?

Given that a single sleepless night can cause people to be irritable and moody the following day, it is conceivable that chronic insufficient sleep may lead to longer-term disorders. Human physiology and behaviour is regulated by near-24-hour cycles known as circadian rhythms. Functions such as body temperature, hormone production and digestion all work to 24-hour cycles and so when the sleep-wake cycle is disrupted it is no surprise that it can have knock-on effects on your well-being.

Shift work (in particular changing shift patterns) and time zone changes can both cause ‘circadian rhythm disruption’, so as you can imagine pilots are particularly susceptible to circadian rhythm disorders.

In the short term such disorders can produce feelings of fatigue, sleepiness, insomnia, digestive troubles, irritability, impaired mental agility and reduced performance efficiency.

Sleep deprivation is the main issue affecting shift workers, as sleep length and quality will vary depending on the different start and finish times of each shift. After a night shift it can be difficult to fall asleep and sleep longer because of daylight and noise – sleep can be reduced by two to four hours, is more frequently interrupted and is of a poorer quality REM and stage two sleep. In the case of an early morning shift, sleep is reduced by having to wake early and not usually compensated for by an advanced bedtime. Of course, a changing pattern of late and early shifts can further complicate the onset and length of restorative sleep.

A further complication is crossing time zones where pilots must cope with shifted waking hours in a changed environmental context and the loss of external time cues which can lead to circadian ‘de-synchronisation’. Such disruptions to sleep length and quality can lead to sleep disorders.

Indeed ‘shift work sleep disorder’ is a medically understood phenomenon and it is estimated that about 10% of rotating shift workers (aged 18-65) have a diagnosable ‘shift work sleep disorder’. The disorder is characterised by excessive sleepiness and/or sleep disruption for at least one month. In the longer term such sleep disorders can also cause further psychoneurotic symptoms such as chronic anxiety and depression, often needing treatment by therapy and/or medication.

But you don’t need to have a sleep disorder to experience mood disorders as a result of circadian rhythm disruption. When our circadian rhythms are disrupted and our bodies produce hormones at the wrong time of day, it can increase the chance of depression or worsen existing depression. For example, you might be producing melatonin in the day time which can cause you to feel dull, unstable, irritable and moody. Or conversely you might be producing cortisol (the stress hormone) at times when your body needs to rest.

Cortisol is also produced as a result of stress (hence it being commonly known as the stress hormone) so one can see how it is possible that ongoing intensive pilot rosters combined with sleep disruption can lead to elevated cortisol levels, which in turn can lead to ‘free floating anxiety’ or distress.

Some people are genetically predisposed to cope with the demands of shift work, where others may struggle, or fall somewhere in between. Some people are clearly ‘morning larks’ and some are ‘night owls’, but also your age, gender, circadian structure, hardiness, neuroticism and sleeping habits can affect your ability to cope. Where some airline fatigue management and mitigation techniques are limited is their ability to predict individual pilot sleepiness as they almost always assume an equal response across all individuals.

Have you been affected by any of the issues raised in this article? Would you be prepared to anonymously share your story to raise awareness of this issue? If so, please email fatiguegroup@balpa.org

We continue our focus on the long-term effects of fatigue next week when we look at burnout, what it is, how it can happen and what can be done to tackle it.