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Air and ground crews are often given rest opportunities at atypical times, outside of a normal entrained circadian sleep period. Due to normal human biology, this practice often leads to delayed, thus shortened, sleep as well as restless sleep. In such cases, a sleep promoting or "No-Go" medication may be prescribed to promote a more restorative crew rest. This study compared two doses of the hypnotic zolpidem, two doses of melatonin and placebo for their effects on daytime sleep, on nighttime cognitive performance and on mood in an operationally and militarily relevant paradigm. The participants worked all night. Subsequently, an Early Group slept from 0800-1600 and a Late Group slept from 1400-2200. The participants worked all night again. Measures included polysomnography, simple and complex cognitive task performance, vigilance, subjective reports, salivary melatonin, and vital signs. Neither zolpidem nor melatonin was successful in improving daytime sleep compared to placebo. Participants slept longer under the medicated treatments, but it was not statistically significant. Sleep inertia was deepened by the use of zolpidem and may prolong degraded performance, sleepiness and fatigue. In this study, there were no advantages for morning or afternoon sleepers for nighttime alertness, mood or performance. The Foret & Lantin (1972) findings of 34 hours of sleep during the day do not appear to hold for sleep-deprived people sleeping under ideal conditions. For two consecutive work nights, ideal daytime sleeping conditions appear to provide nearly as much sleep as a sleep aid and without any risk to nighttime performance or side effects., Prepared in cooperation with General Dynamic AIS, San Antonio, TX.

Zaleplon appears to be a prime candidate for assisting individuals in obtaining sleep in situations not conducive to rest. The primary objective of this study was to determine whether zaleplon (10-mg) effectively promoted sleep during the daytime in well rested individuals when compared to placebo. A secondary objective was to see if, while not expected, the use of zaleplon impacted the performance of these well rested indivIduals upon awakening. Twelve participants, 6 males and 6 females, participated in this study. The study was conducted using a repeated measures design with two within-subject factors: dmg (placebo/zaleplon) and trial (hourly testing during waking hours). Each participant experienced both drug conditions, with drug administration being counterbalanced and double-blinded. During a 3.5 hour nap following drug administration, polysomnographic variables were recorded to measure quality of sleep. Performance measures (cognition, memory, balance, and strength) and subjective reports were collected during every waking trial of each session. Total sleep time, and consequently, sleep efficiency, was statistically higher under zaleplon than under placebo (sleep efficiency = 87% and 76%, respectively). The majority of the gain in sleep occurred during sleep stages 3 and 4. Unexpectedly (given that the participants were well rested) a few of the cognitive performance and memory variables showed improvement after awakening under zaleplon when compared to placebo. Zaleplon, when used by rested individuals for daytime sleep, improves sleep quality., Prepared in cooperation with NTI, Inc., Brooks City-Base, TX.

Primary objective was to determine if zaleplon (10-mg) negatively impacted human performance, compared to placebo, after a sudden awakening from a short period (1 hour) of daytime sleep 16 volunteers, 8 males and 8 females, were formed into 4 groups of 4 participants each. The study used a repeated measures design with 2 within-subject factors drug and trial. Each participant experienced both drug conditions. Drug administration was counterbalanced and double-blinded. Performance measures (cognition and memory, balance, strength) and subjective reports were collected during every waking hour. Performance was significantly negatively impacted in the zaleplon condition up to 3-hrs post-dose. A few measures remained significantly below baseline at 3-hrs post-awakening. All measures returned to baseline by 4-hrs post-awakening. Caution is advised regarding daytime zaleplon use in operational settings involving extreme environments or emergency procedures that include higher cognitive tasks. Findings support insertion of a minimum of lO-min recovery time prier to any work activities following a daytime nap.