Night shift paralysis in air traffic control officers

Abstract

In an earlier paper (Folkard et al. 1984) we reported on the incidence of a temporary but incapacitating paralysis known as ‘night shift paralysis’. This appeared to be a special form of sleep paralysis that occurs when night workers manage to maintain a state of wakefulness despite considerable pressures to sleep. The incidence of this paralysis might thus be assumed to reflect the level of sleep deprivation associated with different shift systems or individuals. The present survey was designed to examine this possibility in a sample of 435 Air Traffic Control Officers (ATCOs) from 17 different countries who were on a variety of different work schedules. The incidence of this paralysis was found to be affected by four main factors, all of which might reasonably be assumed to influence the night-worker's level of sleep deprivation or sleepiness. These were the time of night, the number of consecutive night shifts, the requirement to work both a morning and a night shift starting on the same day and individual differences in the flexibility of sleeping habits. These results suggest that the incidence of this paralysis may indeed prove to be a useful ‘critical incident’ for comparing the level of sleep deprivation associated with different shift systems or individuals.

Keywords:

• Circadian rhythms
• Shift work
• Sleep deprivation
• Paralysis
• Individual differences