Fatigue

Question 1

Define fatigue

Answer 1

Sleepiness and mental degradation

Fatigue is a state of reduced physical and mental capacity as a result of loss of sleep, extended wakefulness, circadian phase or significant physical or mental workload

Question 2

How much sleep do we need

Answer 2

8-10 hour

Question 3

Sleep architecture

Answer 3

Non REM sleep stages 1-4 - allows body to rest
REM sleep to allow the Brain to rest.

Being woken from deep you need to reboot
REM sleep wake up is better.

Question 4

What are the 3 Basic mechanism of fatigue

Answer 4

Homeostatic component
Circadian component
Sleep inertia

Question 5

What is the homeostatic mechanism of fatigue

Answer 5

It is the amount of fuel you start the day with and is determined by how much sleep and quality

Question 6

Circadian mechanism for fatigue

Answer 6

Circadian rhythm drives, body temperature, hormone levels, and alertness levels

Sun intrained
- light suppressed melanton

Question 7

Circadian disruptions

Answer 7

Jet lag: rapid time zone shifts

Shift lag: rapid work- hour changes cause disagreements between the body clock and the new work schedule

Question 8

Sleep inertia

Answer 8

Temporary feeling of grogginess and reduced performance immediately after waking

Can take 30min if woken from deep sleep

Question 9

Types of fatigue

Answer 9

Acute/transient fatigue

Cumulative/chronic fatigue

Question 10

Acute fatigue effects

Answer 10

2-3 days

Degrades accuracy and timing
Unconscious acceptance of lower standards of performance - poor decision making. Tends to cut corners

Narrowing of attention - tunnel vision
Reduced ability to integrate information into overall pattern
Loss of situation awareness
Irritability

Question 11

Cumulative fatigue

Answer 11

Need to exclude medial cause

Decreased physical activity
Social withdrawal 
Visible decrement in performance
Increased use of alcohol or stimulants
Appearance of psychosomatic illnesses
Irritability/mood instability
Increased incidence or chronic disease

Can take weeks to months to recovery

Question 12

Cases of fatigue in ADF

Answer 12

Work long hours
Separated from family
Isolated

Question 13

Effect of fatigue

Answer 13

Physcial

• Yawning
• Heavy eyelids
• eye rubbing
• head drooping
• micro- sleeps
• loss of appetite
• physical exhaustion

Task related

• slowed reaction time
• skip routines
• increased carelessness
• reduced ability to follow directions
• reduced checking
• acceptance of increased risk

Mental
- reduced concentration, attention, vigilance, tunneling attention, lapses in STM, reduced decisiveness, reduced SA, Impaired judgement

Emotional
- Reduced communication, wiithdrawn, reduced energy, motivation, irritability and grumpy, loss of sense of humour

Question 14

The order of degraded performance in fatigue

Answer 14

Attention deteriorate first, then judgement, then reasoning, skills deteriorate much later

Question 15

Increase risk compared to duration of shift

Answer 15

Shift >12hour increases risk 4 times

Question 16

Fatigue compared to alcohol intoxication

Answer 16

18 hours awake = 0.05%
20 hour = 0.08%
Out of phase circadian conditions = 0.1%

Question 17

What are self rating for fatigue

Answer 17

Karolinska sleepiness scale
Same - Perelli
Epworth sleepiness scale - good to check on SQN

Good for looking at a lot of people.
Only one piece of the picture
Can put on fatigue report forms

Question 18

Measures ADF do to prevent fatigue

Answer 18

Crew duty limits
Mission planning
Awareness of fatigue
Drugs - hypnotics and stimulants eg coffee
Supervision - it is CO responsible and have authorising officers to sign off aircrew prior to flyiing

Environmental factors

• insist on appropriate quarters
• need to control noise, climate, lighting conditions, work patterns, meals at the right time of day.

Alcohol and medication

Question 19

Effects of alcohol on sleep

Answer 19

Suppresses REM sleep
Leads to more disrupted sleep - rebound wakefulness
Result in increase impairment of performance

Question 20

Strategies for a good sleep

Answer 20

Follow a routine
Make sleep time sacred
Don’t exercise prior to bedtime
Avoid heavy meals close to bedtime
Don’t watch the clock (get up after 30mins)
Avoid caffeine and alcohol

Question 21

Fatigue recovery

Answer 21

Restriction of 1-2 hours sleep per day rapidly builds up sleep debt
7 days sleep deprivation (<4 hour/night)requires 3 days rest for complete recovery
8 weeks of similar deprivation requires 1 month for recovery
There is no acclimatisation to sleep deprivation

Question 22

Steps military take to prevent fatigue

Answer 22

Crew duty limits
Scheduling - tool
- Faitgue avoidance scheduling tool (FAST)
Enforced Napping

Question 23

Effects of napping

Answer 23

Refresh and enhance performance
Sleep cycle 90-112 minutes
Should nap att circadian lows
- 3-5pm and 3-5am
Avoid sleep inertia 15-60 mins

Question 24

Ways to get pilots back into sleep cycle and get over jag lag

Answer 24

Temazepam and zolpidem

Question 25

What is the fatigue decision hierarchy

Answer 25

Does the task need to be done?
Is there another way to achieve the task?
Alternative platform?
RPAS/Satelite?
Does it need to be done in the current timescale?
Does it need to be done by the planned crew?
Better rested crew available
Augmented crew possible
Are there any ways to reduced effects of fatigue
Other to accomplish plan/walk around
Naps/caffeine/drugs/diet

Question 26

3 core factors in fatigue

Answer 26

Continuous hours of wakefulness
Cumulative sleep loss
Time of day