Sleep duration/schedule

V. Sleep Duration and Schedules Sleep as an Independent Variable... 

Until the mid 90s, no study demonstrated the main factors responsible for sleep-related accidents. We questioned, apart from organic sleep disorders, whether modifications of the sleep-wake schedules could be responsible for sleepiness at the wheel. Studying large populations of drivers (22,23), we demonstrated that long-distance driving was frequently associated with sleep curtailment. Our first study (22), performed on a freeway rest stop area in 1993, showed that 50% of drivers (n = 567 drivers) reduced their sleep duration in the 24 hr before departure for a long-distance journey. Ten percent of drivers had no sleep in the 24 hr before the interview. These stunning results could have been explained by a... 

Sleep deprivation affects not only automobile drivers but also many truck drivers. In a study of professional U.S. truck drivers, Mitler et al. (25) recorded the EEG of 20 drivers on four different work schedules. This study demonstrated a mean duration of sleep of 4.78 hr in a 5-day period. Fifty-six percent of drivers presented at least 6 noncontinuous min of EEG-recorded sleep during the driving... 

Signal and Gander (43) concluded that stage 1 sleep significantly contributed to nap benefits. In a review of polyphasic sleep schedules, Stampi (54) proposed that every time the organism falls asleep some process related to the recuperation might be activated, which may be independent from sleep episode duration, and therefore, that overall beneficial effects are related to the number of times the sleep system is activated (within reasonable limits) (p. 172)... 

Up to this point, the focus has been on using stimulants to sustain alertness in situations where sleep is impossible. However, sustained operations do not necessarily entail total sleep deprivation. Frequently, there are brief opportunities for sleep even though the total amount is less than normal. If properly scheduled, these opportunities can significantly sustain alertness and performance. Naps ranging from 15 minutes to several hours in duration can either restore the performance of already sleep deprived personnel or protect personnel who... 

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