Fatigue & Stress

Question 1

What is fatigue?

Answer 1

A physiological state of reduced mental/physical performance resulting from sleep loss, extended awareness, circadian rhythm or workload that affects the ability of pilots to safely fly a/c.

Question 2

What two types of fatigue are there? What can cause them?

Answer 2

Acute: short lived & fixed with 2 nights of undisturbed sleep. Is generally affected by homeostatic factors (amount/quality of sleep & time of wakefulness).
Chronic: fatigue build up without adequate recovery due to time zones, long working hours, min rest, shift work (late fin/early start), high mental workload and poor quality sleep

Question 3

What are the effects of acute/chronic fatigue?

Can you overcome it and realise the extend of fatigue?

Answer 3

A: inattentive, reduced ST memory, easily distracted, reduced reaction time, neglect 2ndry tasks, lack of awareness, increased errors, irritable, decreased communication, forgetful, willingness to accept lower standards.
C: insomnia, weight loss, depression, irritable, lost appetite, poor motivation f performance

No training, motivation or willpower will overcome fatigue, & people are unable to reliably judge the effects/extent of their own fatigue

Question 4

What are the 3 types of symptoms of fatigue? Give a few examples

Answer 4

Mental: difficulty concentrating and remembering what you are doing, attention lapse, errors, unable to anticipate future, not communicating.
Physical: yawning, eye rubbing, heavy eyelids, head drooping, micro sleeps
Emotional: more quiet and withdrawn, lacking energy & motivation

Question 5

How to calculate sleep debt?

Answer 5

Max 16h credit
-1 per hour awake
+2 per hour sleep.
You can accumulate sleep debt, but do not need to pay back hour by hour, just 2 nights unrestricted sleep.

Question 6

Functions of REM/NREM sleep.

Answer 6

REM: strengthening and organising memories and the brain is similar to being awake. This is when we dream. REM deprivation over long periods can have detrimental effects on brain function.
NREM: related to body restoration and brain activity is slower.

Question 7

Describe the stages of sleep

Answer 7

NREM is stages 1-4, cycles from 1234321 and the between both stage 1 is REM. 4th stage is the deepest stages. REM occurs around 90min into sleep. Cycles become shorter toward end of sleep and may even miss stages 3-4.

Question 8

How does alcohol affect sleep? How much is needed to affect you?
How may alcohol affect REM sleep after sleep deprivation?

Answer 8

Promotes early deep sleep and supremes early REM sleep.
0.025%
REM rebound: inc freq & length of REM sleep

Question 9

What effect does alcohol have on the mind & bladder?

Answer 9

Is anxiolytics (relieves anxiety)
Diuretic effect

Question 10

Describe the main points of a circadian clock

Answer 10

Peaks around 0800-1200 highest around 1000
Drops 1300-1500 & body temp decreases in this period
Pick up 1600-2100
Min 0300-0600
0730/2130 melatonin secretion start/stop
Max body temp 1800 lowest 0500

Question 11

What affects zeitgebers? (Time givers)

Answer 11

Light
Hormones
Temp
Social interactions
Drugs
Exercise
Eating/drinking

Question 12

What is the circadian gates?

Answer 12

Time between 3-5 where body clock is at a low

Question 13

What are sleep strategies?

Answer 13

• find chronotype (lark/owl)
• calculate sleep/debt credit
• after night shifts go to bed immediately after shift (otherwise zeitgebers will tell you to stay awake)
• keep room dark, cool and quiet
• eat light on night shifts as digestion less efficient
• don’t exercise before sleep
• naps should be 45m (3-4h alert) or 1.5-2h (12-15h alert) as not in REM sleep or deeper slow wave sleep… be aware sleep inertia
• take advantage of 3-5pm low
• more napping reduces sleep inertia (May last hour if awoken deep sleep)
• keep to routine and aim for 8h sleep
• in the cockpit start conversation, do something physical, caffeine

Question 14

Explain effects of caffeine

Answer 14

Is a CNS stimulant that increases attention (15-20m after injection 3-4h) but decreases performance, coordination and reaction times.
Can increase irritability and cause nervousness and elevate blood px.

Question 15

What is FMS?

Answer 15

Fatigue management system is a data driven means of continuously monitoring and maintaining fatigue related safety risks, based upon scientific principals, knowledge & operational experience that aims to ensure relevant personal are performing at adequate levels of performance/alertness

Question 16

Explain the yerkes Dodson model

Answer 16

Bow shaped curve where decreased arosual is bad for performance while too much is just as bad, somewhere in between performance peaks.

Question 17

What is the startle effect?

How to overcome?

Answer 17

Is due to a sudden unexpected event that causes the pilot to experience an uncontrollable, automatic reflex (mental/physical), fright flight or freeze.
Maintain SA, avoid complacency, over learn procedures, maintain handling skills, have a contingency plan and take deep breath and slow down speech.

Question 18

What does under load cause? Is automation a good example of this?

Answer 18

Complacency, boredom and impulsive risk taking.

Automation may complicate workload but reduce workload

Question 19

Which direction (E/W) is harder to travel for jet lag?

Answer 19

East, as compress body clock which is harder to do as body clock slightly longer than 24h.

Question 20

REAS UP ON CONTROLLED REST WILL BE IN EXAM!

Answer 20

Seriously

Question 21

What is stress? What types of stressors are there?

Answer 21

A nonspecific response of the body when demand is placed on it can be perceived or actual.
Phyosocial
Environmental
Physiological

Question 22

Give examples of phycological & environmental stressors

Answer 22

E: altitude (less 5’ due to trapped gases), speed, temperature, a/c design (light, noise, comfort, airframe characteristics, IMC/night)
P: ie life events, illness, family, job (responsibility, security, confidence, a/c issues)

Question 23

Explain DEATH of physiological stressors

Answer 23

D: drugs (self med, predictable side effects, overdose, allergic reaction/idiosyncratic, combining drugs (synergetic), caffeine)
E: exhaustion (lack of sleep/rest, should excercise)
Alcohol: is a depressant, should not use 12h before flight. Only time will reduce effects.
Tobacco: increase risk of hypoxia due to CO in blood (add 5’ to actual altitude) and decreased night vision + all bad health effects
Hypoglycaemia: caused by irregular meal times. Liver stores glycogen which can readily be converted into glucose, but in deficiency of glycogen glucose blood levels drop, causing tiredness, fainting and inefficiency

Question 24

What type of responses can someone have to stress?

Answer 24

Emotional: increased anxiety, irritability, hostility, depression, hopelessness, low self esteem, unable to enjoy life.
Behavioural: decreased performance/motivation/social. Increase conflict and disregard of rules.
Cognitive: simplification heuristic (in high stress will oversimplify problems and ignore relevant info). Stress related regression (revert to bad habits and forget learnt procedures). Perceptional tunneling (focus one one thing). Reduced cognitive capacity & working memory. Perceived time restrictions.
Physical: increased heart rate, blood px, arousal, breathing, muscle tensioning, adrelinine and blood sugar to fight/flight

Question 25

How to avoid/reduce stressors?

Answer 25

A: SA, plan, foresight, training, time management, problem solving
R: positive self talk, take responsibility of actions, avoid perfectionism and inflexibility of thinking, focus on present, relaxing technique, ventilate somehow (tackle, talk, exercise)

Question 26

What is burnout?

Answer 26

Persistent chronic fatigue so they cease to function normally

Question 27

Summary of reducing fatigue

Answer 27

Control sleep environment, adjust to shift work, be fit/healthy, eat well, limit/control caffeine/alcohol, good time management, take naps and maintain good working environment