| Sleep inertia (SI) defines a period of transitory hypovigilance, confusion, disorientation of behavior and impaired cognitive and sensory-motor performance that immediately follows awakening. SI, the cognitive and behavioral correlate of the transition from sleep to wakefulness, has been incorporated in several models of sleep and vigilance regulation. SI is one of the most serious contraindications to the use of napping during quasi-continuous operations if the individual may be required to perform complex tasks immediately after sudden awakening at unpredictable times. In a military crisis, sleep deprivation (SD) is a usual phenomena which is one of causes that can lead to fatigue, loss of battery effectiveness and depletion of numbers. Nap is an effective countermeasureagainst SD, so SI after nap must be considered. Our studies on SI, firstly, is to validate the exist of SI after siesta in a natural states, and analyze how to influence on cognitive performances during SI, as well as to choose some more sensitive tests to measure the negative effects of sleep inertia. Farther, we evaluated effects of 30h sleep deprivation and Ih nap factors on cognitive performance upon awakening in the studies. At the same time, the results of subjective test compared with the scores of cognitive performance test. Finally, this study sought to establish the effects of coffee on sleep inertia. There were mainly three parts in our studies.First, Effects of sleep inertia in the normal condition on cognitive functions.Objective: To investigate the influence of sleep inertia after siesta on cognitive functions. Methods: The 10 healthy male youths took part in the study. An electroencephalogram machine was used to record the conditions of subjects' falling asleep at noon. The subjects were awakened after they had been asleep for 60 minutes, then their cognitive functions were tested immediately including: test of successive calculation( TSC), orientation-2D test(O-2D) , letter cancellation test(LCT), verbal and space work memory test(VSWMT). They were tested twice after awakened and there was 20 minutes between the first and the second test. The results of two tests were compared each other and with the baseline. Result: In orientation-2D test and space work memory test, the results only revealed a statistically significant decrease in the result of the first tests compared with that of the baseline (p<0.05). In the test of successive calculation and letter cancellation test, there are statistically differences in the result of the first test compared with that of the second test and the baseline (P<0.05). There was no statistical difference between the result of the second test and that of the baseline.In the verbal work memory test, the results after awaken were under the baseline all along (P<0.05). Conclusions: sleep inertia induced different effect in different aspects of cognitive tests. It normally lasts some time that can be longer than what it had ever been considered to be 10-20 minutes. Cognitive tasks involving high attentional load seem to be much more affected by SI than simple motor ones.Second, Effects of sleep inertia on cognitive functions and mood after sleep deprivation.Objectives: To study the effect of a 1 hour nap on cognitive performance and mood after 30 hours sleep deprivation, and to evaluate the process of gradual recovery from sleep inertia. Methods: Eight healthy male volunteers participated in this study. They attended a series of tests including three parts: the Successive Addition Tests, the Work Memory Tests, POMS and VAS tests after 1 hour nap during which EEG was recorded. The series of tests had been done 5 times immediately after the volunteers were awoken and each lasted about 10 minutes with an interval of 20 minutes between tests. The cognitive performance of 5 times was compared across times and with the best cognitive performance in awakening to estimate whether or not the cognitive abilities regained the normal condition. The results of nap group compaire wit...
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