Fatigue Flashcards
Define fatigue
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
How much sleep do we need
8-10 hour
Sleep architecture
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.
What are the 3 Basic mechanism of fatigue
Homeostatic component
Circadian component
Sleep inertia
What is the homeostatic mechanism of fatigue
It is the amount of fuel you start the day with and is determined by how much sleep and quality
Circadian mechanism for fatigue
Circadian rhythm drives, body temperature, hormone levels, and alertness levels
Sun intrained
- light suppressed melanton
Circadian disruptions
Jet lag: rapid time zone shifts
Shift lag: rapid work- hour changes cause disagreements between the body clock and the new work schedule
Sleep inertia
Temporary feeling of grogginess and reduced performance immediately after waking
Can take 30min if woken from deep sleep
Types of fatigue
Acute/transient fatigue
Cumulative/chronic fatigue
Acute fatigue effects
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
Cumulative fatigue
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
Cases of fatigue in ADF
Work long hours
Separated from family
Isolated
Effect of fatigue
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
The order of degraded performance in fatigue
Attention deteriorate first, then judgement, then reasoning, skills deteriorate much later
Increase risk compared to duration of shift
Shift >12hour increases risk 4 times
Fatigue compared to alcohol intoxication
18 hours awake = 0.05%
20 hour = 0.08%
Out of phase circadian conditions = 0.1%
What are self rating for fatigue
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
Measures ADF do to prevent fatigue
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
Effects of alcohol on sleep
Suppresses REM sleep
Leads to more disrupted sleep - rebound wakefulness
Result in increase impairment of performance
Strategies for a good sleep
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
Fatigue recovery
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
Steps military take to prevent fatigue
Crew duty limits
Scheduling - tool
- Faitgue avoidance scheduling tool (FAST)
Enforced Napping
Effects of napping
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
Ways to get pilots back into sleep cycle and get over jag lag
Temazepam and zolpidem
What is the fatigue decision hierarchy
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
3 core factors in fatigue
Continuous hours of wakefulness
Cumulative sleep loss
Time of day
