Sleep References
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Bonnet MH, Arand DL
The use of prophylactic naps and caffeine to maintain performance during a
continuous operation
Ergonomics 1994; 37:1009-20
After a normal baseline night of sleep and a morning of baseline test
performance, 24 young adult male subjects returned to bed from 16:00-20:00
prior to a 24 h period of sleep loss. Twelve subjects received caffeine 200 mg
at 01:30 and 07:30. Performance tests (correctly completed addition problems,
vigilance sensitivity, and logical reasoning correct responses) all indicated
maintenance of baseline performance levels in the caffeine group after
administration of caffeine while performance declined in the placebo group.
Similar results were found for the Multiple Sleep Latency Test and Oral
Temperature, which both remained near baseline levels throughout the
observation period in subjects receiving caffeine. The results indicated that
the combination of a prophylactic nap and caffeine was more effective in
maintaining nocturnal alertness and performance than was the nap alone. Of
more interest was the fact that the group which was given the combination of
nap and caffeine was able to maintain alertness and performance at very close
to baseline levels throughout a 24 h period without sleep.

Bonnet MH, Gomez S, Wirth O, Arand DL
The use of caffeine versus prophylactic naps in sustained performance
Sleep 1995; 18:97-104
Previous studies have shown that performance during sleep loss is improved by
prophylactic naps as a function of varying nap length. Based on single-dose
caffeine studies, a similar dose-response effect has been hypothesized on
performance, alertness and mood during sleep loss. The present study compared
the effects of repeated versus single-dose administration of caffeine and
varying amounts of sleep taken prior to sleep loss on performance, mood and
physiological measures during 2 nights and days of sleep loss. A total of 140
normal, young adult males participated at one of two study sites. Ninety-eight
subjects at one site were randomly assigned to one of four nap conditions (0,
2, 4 or 8 hours) and 42 subjects at the second site were assigned to one of
four caffeine conditions. After a normal baseline night of sleep and morning
baseline tests of performance, mood and nap latency, subjects in the nap
groups returned to bed at noon, 1600 hours, 1800 hours or not at all. Bedtimes
were varied so that all naps ended at 2000 hours. Subjects in the caffeine
groups received either a single 400-mg dose of caffeine at 0130 hours each
night or repeated doses of 150 or 300 mg every 6 hours starting at 0130 hours
on the 1st night of sleep loss. A placebo control group (no nap and placebo
administered every 6 hours on the repeated caffeine schedule) was run at both
sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Bonnet MH, Arand DL
Impact of naps and caffeine on extended nocturnal performance
Physiol Behav 1994; 56:103-9
It was hypothesized that alertness and performance during an extended work
period would be improved by an afternoon nap and the subsequent use of
caffeine during the night. Twelve young adults received a 4-h afternoon nap
and caffeine during the night during one session and four 1-h naps during the
night in a second session. After an afternoon nap, subjects had increased
objective and subjective alertness, increased oral temperature, and increased
performance on complex tasks like logical reasoning and correct additions when
compared to the condition that allowed four nighttime naps. It was concluded
that the specific scheduling of a nap period in preparation for an all-night
work shift where sleep would not be allowed could result in increased
alertness and performance as well as a less conflicted work situation.