Stress, Arousal & Fatigue Chapter 5

AimTo understand what stress is and what risks it presents for aviation safety. To learn what fatigue is and how it can be managed

Objectives1. To understand what stress is and the types of

stress2. To learn how we can avoid stress and how it can

be managed3. To learn what fatigue is and the causes4. To understand what stressors we face as pilots

1. StressWhat Is Stress

Stress is a disturbing physiological or psychological influence on human performance that has the ability to impact adversely on the safe conduct of a flight or situationIt is a process, not a diagnosis

A natural reaction to a stressor

Not all stress is badWithout stress, we wouldn’t be compelled to act or react to stimuli

1. StressTypes of Stress

Acute stressMost common form of stressImmediate and disappears after a short timeThrilling and exciting in small doses

EpisodicExtended acute stressTaking on too much, always rushing, often late, overbooked, etc.Becomes the ‘norm’ after a while, ingrained in lifestyle

ChronicDangerous stress, leads to psychological and physiological illnessPrevention is better than cure

1. StressTypes of Stress

Stress normally starts at a level that most will cope with, however as it builds up without suitable rest, it can overwhelm

E.g. A looming exam motivates you to study. A secondary assignment due around the same time with minimal notice may give you the kick to get working

Subsequent workload may be managed, however any additional stressors (such as a relationship breakdown or personal crisis may critically limit one’s ability to cope)

2. Avoiding StressAvoidance techniques

As pilots, what can we do when we get stressed? Can we say ‘enough’

Avoidance is not an option. We cannot simply turn a blind eye or leave the stressful cockpit situation

So, what can we do? Some typical avoidance techniques include:• Lack of awareness (i.e. shutting off the brain and reverting to a gaze)• Rationalisation• Phantom illnesses• Day dreaming • Resignation • Anger• Substance-directed coping (e.g. drugs and alcohol)

Avoidance techniques

We must be able to cope using acceptable means:• Break the task down into a series of more manageable items• Allow plenty of time – don’t get behind the aircraft• Make early decisions• Don’t let ATC direct you into an unsafe condition• Don’t be distracted from checklists• Don’t allow interruption or change to usual routine• Ask ATC to standby (Aviate, Navigate, Communicate)• Do not press on into unsafe conditions (e.g. weather or limited

daylight)

2. Avoiding Stress

Arousal – stress as a motivator

Stressors can increase arousal to prepare for action (e.g. a flight test)

Other stimuli can decrease arousal and hinder performance (e.g. fatigue)

Optimal arousal chart

The curve shifts depending on the complexity of the task

2. Avoiding Stress

2. Avoiding StressCoping with stress

Exercise regularly - Some form of rigorous aerobic at least 20 minutes 3 times a week

Avoid conflict - Where possible, avoid unnecessary arguments and conflict. Although ignoring a problem is not always the best way to reduce stress Assertiveness is fine but becoming distressed is not

Relax - Allow time each day to spend time with people who make you feel good about yourself and do things you enjoy and feel relaxed doing

Eat well - A nutritious diet is important. Fresh fruit and vegetables (avoid sweet and fatty foods)

Sleep – Relaxing before sleep will help with sleep onset and quality

Enjoy your life – If you’re not, Change It!

3. FatigueFatigue – A hindrance to health

Fatigue is not the same as being tired

Typical manifestations of fatigue include:• Lack of awareness, diminished motor skills• Tiredness (yawning, droopy head, hard to keep eyes open)• Slow reactions and difficulty focusing• Reduced efficacy of short term memory• Tunnel vision• Being easily distracted• Poor instrument scan• Increased mistakes, errors in judgement and execution• Abnormal moods

Fatigue can be minimised by managing workload effectively

I.M.S.A.F.E. - to ensure you do not fly when fatigued

Sleep

Everyone needs 6-8 hours sleep to function properly (regardless of age)

As you age, sleep becomes less deep and therefore can be less refreshing

Sleep deficit studies suggest that for every 2 hours of wakefulness, an hour of sleep is required (8hours sleep for 16hours wake)

Sleep lost can only be fixed by more sleep, not energy drinks or caffeine

3. Fatigue

Sleep - Tips

Exercise - Regular exercise benefits sleep, however should not be just before going to bed. Early morning or afternoon is best

Snacks - a light snack before going to bed might help getting to sleep, unless it causes associated indigestion/gastric discomfort. Avoid heavy meals and caffeinated drinks before going to sleep. Warm milk has been shown to assist sleep onset

Alcohol – Alcohol before bedtime may help with sleep onset, but it does not assist quality sleep. Alcohol disturbs the brain’s natural progression into deeper, beneficial sleep, also rendering you likely to wake in the middle of the night

Ensure a sound sleeping environment – Minimise disruptions at bedtime, e.g. television, smartphones, reading. Ensure the bed and bedroom is comfortable

3. Fatigue

Caffeine

Blocks the neurochemicals responsible for sleep onset, making one feel more alert

Restricts blood vessels in the brain, reducing one’s performance

Increases one’s performance in simple tasks and decreases performance in more complex tasks (i.e. flying an aeroplane!)

3. Fatigue

4. StressorsEnvironmental or physical

Hot, cold, noisy, damp, dry, turbulent, vibrating, dark, light, smelly, lacking oxygen

In extreme heat (over 35 degrees C), the body struggles to maintain homeostasis (trending toward hyperthermia). Perspiration, heart rate and blood pressure increase especially in humid conditions. Attention span reduces and one becomes stressed. Reactions to emergency may be limited or dangerous

In cold environments, the body sends blood to the core rather than extremities to keep internal temp around 36.5degrees. Heat can be lost through:

• Exposed areas of skin, especially the head• Wind chill• Evaporation of sweat especially in dry environments

In low temperatures, the body may shiver to generate warmth. Optimal temperature is between 20-26 degrees C

Environmental or physical

Vibrations can be uncomfortable, distracting and exhausting, especially when the vestibular system has to track the head movement

In turbulence, movements are unpredictable and can cause sickness, further exacerbating the workload

Noise can cause stress and fatigue. Attention is more difficult in higher noise environments, leading to added stress

Airsickness is debilitating - IMSAFE

Impaired vision or poor lighting requires more energy to focus, thus increasing fatigue

4. Stressors

4. StressorsIntellectual, psychological or emotional

Relationships at home or work or other stresses can take priority of the limited mental space and decrease available energy for stressors.

Over-arousal leads to performance detriment (tunnel vision)

Chapter 5

Questions?