Aeromedical: Fatigue Flashcards
FATIGUE
The state of feeling tired, weary, or sleepy that results from prolonged mental or physical work, extended periods of anxiety, exposure to harsh environments, or loss of sleep.
Acute Fatigue.
Associated with physical or mental activity between 2 regular sleep periods.
Loss of awareness of errors & coordination first to develop.
Crew members feel this tiredness at night after being awake for 12 to 15 hrs in a day.
Characterized by: inattention, distractibility, errors in timing, neglect of secondary task, loss of accuracy & control, lack of awareness of error accumulation, & irritability
Chronic Fatigue.
Result of inadequate recovery from successive periods of acute fatigue.
It may take several weeks of rest to completely eliminate chronic fatigue & there may be underlying social causes, such as family or financial difficulties.
Characterized by: insomnia, depressed mood, irritability, weight loss, poor judgment, loss of appetite, slowed reaction time, poor motivation & performance on the job.
Motivational Exhaustion or Burnout.
If chronic fatigue proceeds untreated for too long, the individual will eventually “shut down” & cease functioning occupationally & socially.
DIURNAL (CIRCADIAN) RHYTHMS & FATIGUE
We have an intrinsic biological clock with a cycle of roughly 24 to 25 hours, & many important bodily functions such as core body temperature, alertness, heart rate, & sleep cycle occur along these diurnal rhythms.
Circadian Desynchronization
aka Jet Lag
Rapid travel from one time zone to another causes the body to resynchronize its diurnal rhythms.
Sleep disorders & fatigue will prevail.
Resynchronization occurs more rapidly when traveling west.
THE SLEEP CYCLE
The sleeping brain cycles between rapid eye movement & non-REM sleep through five stages.
Cycling occurs every 90 minutes.
The duration & quality sleep depend on body temperature.
It is the timing of sleep, not the amount that matters.
A sleep schedule that is inconsistent w / ones circadian rhythm & the light & social cues of the environment will ultimately result in fatigue.
Frequent changes in sleep patterns may also result in fatigue.
Sleep efficiency deteriorates with age.
SLEEP REQUIREMENTS
During operations in which sleep loss is expected, aircrew members should closely monitor each others behavior for indications of fatigue.
Avg person sleeps 7 to 9 hrs per day.
Sleep length can be reduced 1-2 hrs without performance decrement over an extended period.
As a RULE, five hours of sleep per night are the minimum for continuous operations (for example 14 days).
PREVENTION OF FATIGUE
Control the sleep environment
adjust to shift work
maintain good health & physical fitness
practice good eating habits
practice moderate controlled use of alcohol & caffeine
plan & practice good time management
practice realistic planning
maintain optimal working conditions
take naps
Treatment of Fatigue.
The most important action is to get rest & natural (not drug induced) sleep.
Alcohol is the number one sleep aid in the U.S., but it suppresses REM sleep.
If you find yourself lying awake more than 30 minutes; get out of bed & read a boring book or listen to some relaxing music.
When attempting to recover from 24 to 48 hrs of sleep deprivation; do not sleep longer than 10 hrs.
