Sleep And Fatigue Flashcards
34.40.2/46.40.2 Describe the 5 stages of sleep
Stage 1: Transitional phase between sleeping and waking. Person begins to relax, and slow rolling eye movements begin. The sleep lasts 1 – 10 minutes
•Stage 2: Lasts 10 minutes
•Stage 3 and 4: Slow wave sleep
•Stage 5: REM sleep, eye movement is rapid and muscles are relaxed. REM sleep is when dreams are recalled.
34.4.4/46.40.4 Describe the mechanism of sleep regulation
The human body relies on the circadian rhythms to regulate sleep. It has been proven though that if humans were put in a room (temporal isolation) the free running cycle for humans is 25 hours.
However external factors such as light, social activities and meals adjust this to 24 hours.
•Another regulator is body temperature, you wake with a rising temperature but fall asleep with a falling temperatures.
34.40.6/46.40.6 Describe problems associated with sleep at abnormal times of the day
When your circadian rhythms are disrupted or thrown off, you may feel groggy, disoriented, and sleepy at inconvenient times.
• Circadian rhythms have been linked to a variety or sleeping problems and sleep disorders, including insomnia, jet lag, and shift work sleep difficulties.
34.40.8/46.40.8 Explain what is meant by sleep debt
Sleep is similar to a credit card. Every hour you sleep earns +2 points, every awake hour spends -1 point.
Therefore 8 hours of sleep give you 16 points to use throughout the day. The body can only store a certain amount of sleep. If you are spending more than earning you go into sleep debt.
46.40.10 Describe what is meant be sleep inertia, when is it most likely to occur and how long it takes to wear off
Sleep Inertia is a physiological state characterised by a decline in motor dexterity and a subjective feeling of grogginess immediately following an abrupt awakening.
The severity and time to recover depends on three factors:
- The depth of sleep when woken–REM sleep is the worst
- The timing of sleep–Related to the circadian rhythm
- Chemical Influence–Caffeine
•On average 15 minutes to recover form sleep inertia.
34.40.10 Explain how individuals differ in their requirement for sleep (2)
- At different ages we require different amounts of sleep.
- It is the individual’s homeostatic mechanism that makes them feel sleepy and tells them when they have had enough sleep.
34.40.12/46.40.12 Explain the effects of the following alertness management techniques, napping, caffiene, sedatives, stimulants other than coffee
a) napping
•Naps of less than 45 minutes do not result in sleep inertia. Use napping sensibly before a shift
- b) caffeine
- Caffeine may be used as a short-term solution and can be very effective when coupled with a nap.
c) taking sedatives
•Sedatives act on the central nervous system and may suppress mental alertness. Melatonin has been promoted to help sleep and cure jet lag, but it should not be taken without advice from a specialist.
•Sleep inducing drugs are sometimes prescribed, when these are prescribed, they need to be used to cure situational NOT clinical insomnia.
d) taking stimulants other than caffeine
•If stimulant such as Dexadrine and Benazadrine are required to stay awake a pilot is unfit to fly
•Any such “pep pills” impair judgement and cause a dangerous level of over confidence.
34.40.14 Describe the main sleep disorders and their effects on pilot performance
Clinical Insomnia – Difficulty sleeping in normal circumstances; an inability to sleep when the body requires sleep.
•Situational Insomnia – Difficulty sleeping because the biological rhythms are disturbed due to travel and shift work.
Describe the other sleep disorders and their effects
Sleep Walking/Sleep Talking – Neither usually pose a problem to pilots.
- Narcolepsy – Sufferers fall asleep even when involved in a situation requiring their full attention. This would preclude a flying career.
- Sleep Apnoea – Temporary cessation of breathing during sleep, may cause the sufferer to wake often causing sleep deprivation.
Define fatigue
a condition characterised by increased discomfort with lessened capacity for work, reduced efficiency of accomplishment, loss of power or capacity to respond to stimulation, and usually accompanied by a feeling of weariness and tiredness
34.40.16 Explain the causes of fatigue (7) and its effect on pilot performance for short haul and long haul pilots
- Disturbed or insufficient rest •Low humidity (dehydration) •Glare •Vibration •Noise •Anxiety •Disturbance of biological rhythms
Short haul pilots are often unable to compensate for early wake ups by falling asleep earlier. Therefore multi-leg duties and repetitive early starts are main causes of fatigue.
- Long haul pilots also encounter fatigue from long flights and crossing multiple time zones
- Fatigue ultimately leads to pilot error.
34.40.18 physical symptoms of fatigue (5)
- General feeling of tiredness •Reduction in vigilance •Growing and irresistible need to sleep and inadvertent napping •Lethargy •Slowed reaction time
Mental symptoms of fatigue (6)
- Difficulties memorising information and forget things •Lack of concentration •Slow understanding •Bad mood •Poor decision making •Apathetic
34.40.20 Explain the difference between acute and chronic fatigue
Acute: Short term – related to current activities and the pilot will recover when the situation resolves itself. Acute fatigue is easily recognised and fixed by not flying.
•Chronic: Long term – more serious and there is a cumulative effect, this makes the body susceptible to illness and increased stress. It can be difficult to recognise, a pilot must stop flying.
34.40.22/46.40.14 Describe methods of managing fatigue (6)
Fatigue Risk management Systems (FRMS)
●Be well rested before reporting for duty
●Maintain good sleep habits
●Maintain a high level of physical fitness
●Eat regular, balanced and nutritional meals
●Avoid excessive use of alcohol
●Good mental health.
Define biological clock, circadian rhythm, circadian dysrhythmia, desynchronisation, zeitgeber
Biological clock - mechanism that controls the physiological activities of an organism which change on a daily, seasonal, yearly, or regular cycle.
Rhythm - physical, mental and behavioural changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in an organisms environment.
Dysrhythmia - disturbance in the circadian rhythm
Desynchronisation - trans meridian desynchronisation, change in time zones
Zeitgeber - time givers - daylight and meal times
34.40.26/46.40.18 Describe the central human physiological processes underlying circadian rhythm processes
We wake with an increasing body temperature and fall asleep with a decreasing temperature.
- Performance increases with an increase in body temperature and decreases as temperature decreases.
- Verbal and mental reasoning peak around midday
- Some physiological functions are depressed at night.
34.40.28/46.40.20 Explain how circadian rhythms affect pilot performance
When pilots are operating outside of the regulated rhythm, performance decreases and the effects of circadian dysrhythmia will be more likely.
34.40.30/46.40.22 Explain the effects of circadian dysrhythmia and methods of managing these ( 4 effects)
Increased reaction time •Decreased attention •Impaired memory •Emotional Irritability •In Aviation this results in more error, more incidents and higher risk
Reset body clock by spending more time in the daylight, be more active, avoid adjusting to new Timezone if there for less than 48 hours.
Rate of adjustment to crossing time zones in both east and west directions
Adjustment to the new time zone is faster for east–west travel than for west–east. 18-24 hours for 1 hour of adjustment, fully adjust after 3-5 days
46.40.26 Why rate of adjustment to crossing time zones varies eastwards and westwards
Travelling east the body clock must be advanced, which is more difficult for the majority than delaying it
- Most people have an endogenous circadian rhythm that is longer than 24 hours, so lengthening a day is less troublesome than shortening it.
- Equally important, the necessary exposure to light to realign the body clock does not tie in with the day/night cycle at the destination.
34.40.32/46.40.28 Describe the impact of shiftwork on pilots performance (4)
Circadian rhythms are only partially adapted to current work/rest schedule
- Most shift workers revert to being day-active on days off
- Sleep deprivation is a fact of life for commercial aircrew
- Fatigue can occur due to sleep deprivation
34.40.34/46.40.30 Describe how the biological effects of shiftwork can be minimised
Rotate shifts
Phase delay/advance – gradually change the time you sleep and wake
•Bright lights as mimic daylight
•Sensible napping
•Regular balanced meals and limited alcohol
34.40.36/46.40.32 Identify the principles of good rostering practice (long haul)
- Consideration to the length and number of sectors to be flown
- Length of total duty
- Avoid rostering night flights following transmeridian flight
- Transmeridian flights should be altered with ones in the same timezone to allow the circadian rhythm to reset.
34.40.36/46.40.32 Identify the principles of good rostering practice (short haul)
Limit number of early starts (2 maximum)
•Limit the number of late finishes (3 max)
•Alternate morning and afternoon duties
•Avoid short nights off that finish late and start early
