– periods of inattention,
– reduction in alertness level,
– slow actions,
– alteration in short-term memory,
– loss of critical analysis and advocacy,
– interpretation errors,
– visual illusions,
– disorientation.
Effects on mood:
– sensation of fatigue,
– depressive state,
– irritability,
– loss of interest in people and events,
– increasing and irresistible longing for sleep.
Most altered tasks:
– sustained tasks,
– tasks without stimuli,
– routine work,
– supervisory monitoring tasks,
– insufficiently learnt tasks,
– tasks with high workload,
– tasks requiring complex decision-making.
( after British Army Personnel Research Center, 1986). Cited in Lagarde, 1990
6.4.4.3. MODULATIONS OF THE EFFECTS OF SLEEP LOSS
Noise: in normal situations, noise has too high an activation effect leading to a reduction in efficiency, but it facilitates efficiency when associated with sleep loss (Wilkinson, 1963). Sleep loss reduces the cerebral activation level, noise moves this level towards the optimum.
Alcohol: associated with a sleep deprivation, reduces the wakefulness level and, in parallel, degrades mental performance.
Moderate physical exercise: increases cerebral activation.
Validating Active/Passive crew alternation at Air France on A340 in 1994
Validating Crew Rest on board with dedicated sleep bunks on A340 in the early 90’s
6.5. SLEEP & NAPPING
6.5.1. SLEEP
6.5.1.1. DESCRIPTION–NORMAL SLEEP
Sleep onset is a periodic phenomenon that occurs every day at almost the same time.
Sleep generally starts at the end of the day, when the body temperature begins to drop and it continues so for 6 to 8 hours.
Spontaneous awakening occurs during the ascending part of the thermal cycle, that is 2 to 3 hours after the thermal minimum which, on average, takes place around 5am.
The polygraphic study of sleep, recording of cerebral activity, muscular tone and eye movements, allows the various increasing depth stages to be separated:
– Stage 1: sleep onset,
