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The hypothesis that sleep deprivation depresses immune function was tested in 20 adults, selected on the basis of their normal blood chemistry, monitored in a laboratory for 7 d, and kept awake for 64 h. At 2200 h each day measurements were taken of total leukocytes (WBC), monocytes, granulocytes, lymphocytes, eosinophils, erythrocytes (RBC), B and T lymphocyte subsets, activated T cells, and natural killer (NK) subpopulations (CD56/CD8 dual-positive cells, CD16-positive cells, CD57-positive cells). Functional tests included NK cytotoxicity, lymphocyte stimulation with mitogens, and DNA analysis of cell cycle. Sleep loss was associated with leukocytosis and increased NK cell activity. At the maximum sleep deprivation, increases were observed in counts of WBC, granulocytes, monocytes, NK activity, and the proportion of lymphocytes in the S phase ofthe cell cycle. Changes in monocyte counts correlated with changes in other immune parameters. Counts of CD4, CD16, CD56, and CD57 lymphocytes declined after one night without sleep, whereas CD56 and CD57 counts increased after two nights. No changes were observed in other lymphocyte counts, in proliferative responses to mitogens, or in plasma levels of cortisol or adrenocorticotropin hormone. The physiologic leukocytosis and NK activity increases during deprivation were eliminated by recovery sleep in a manner parallel to neurobehavioral function, suggesting that the immune alterations may be associated with biological pressure for sleep. (J. Clin.

Quasi-continuous work settings often involve sleep loss and requirements to perform at unpredictable times. Napping may alleviate some of the sleep-loss problems, but it increases the risk that the person will have difficulty functioning upon abrupt awakening. This paper describes an experimental approach, techniques, and analyses for investigating performance upon abrupt awakening from 2-h naps placed near either the circadian peak (P) or trough (T) in body temperature and preceded by 6, 18, 30, 42, or 54 h of sleep deprivation. Five groups of healthy young adults performed quasi-continuously for 54 h and were permitted a 2-h nap at one of five times. Reaction time (RT) to answer a phone terminating the nap, subjective estimates, and performance of a brief, challenging cognitive task were related to nap-sleep parameters of each group. Sleep deprivation increased the amount of deep sleep in the naps, and this was associated with greater postnap cognitive performance decrements; subjective estimates were unaffected, and RT performance was related simply to stage of sleep prior to awakening. Circadian placement of the naps also modulated the postnap cognitive decrement: T naps produced greater cognitive decrements than P naps, even when the latter involved more prior sleep loss. These findings have both practical and theoretical significance for evaluating the awakening process, and would not have been possible without the approach, techniques, and procedures described.There is a fundamental dilemma faced in planning sleep logistics for quasi-continuous work situations, such as those often encountered in the military. The person may have to perform at full capacity, at a moment's notice, at unpredictable times, over a period of many days, weeks, or months. If the individual is kept awake throughout the period, the inevitable effects of sleep deprivation take their toll, performance deteriorates, and involuntary sleep onsets become commonplace. If, on the other hand, the person sleeps, performance upon abrupt awakening from sleep may be severely compromised.Paradoxically, people actually function less well immediately upon awakening from sleep than they do prior to going to sleep (Kleitman, 1963), although the detrimental effect does not usually last beyond 15 to 30 min after subjects awaken. Decreased performance upon sudden awakening from sleep has been shown to occur for a broad range of tasks, including simple reaction time (RT) (Dinges, Orne, Evans, & Orne, 1981;Okuma, Nakamura, Hayashi, & Fujimori, 1966 Gillberg, 1979;Bonnet, 1983;Grosvenor & Lack, 1984;Stones, 1977), time estimates (Carlson, Feinberg, & Goodenough, 1978), complex-behavior simulation tasks Hartman, Langdon, & McKenzie, 1965;Langdon & Hartman, 1961;Seminara & Shavelson, 1969), and a number of cognitive tasks, such as mental arithmetic, cancellation, and clock reversal (Dinges et al., 1981;Fort & Mills, 1972; Pritchett, 1964 Pritchett, /1969Scott, 1969;Tebbs, 1972; Wilkinson & Stretton, 1971).Not only is the immediate postsleep performance dec...

Some children and adolescents with sickle cell disease experience frequent painful episodes. To gain information about the natural history of the pain and its impact on sleep and school attendance, we developed a home-based diary system. Eighteen children and adolescents completed 4756 diary days, with an average compliance of 75%. Pain was reported on 30% of days and was managed at home nine-tenths of the time. Girls reported more days with pain than did boys, and age was positively correlated with the length of the painful episodes. The pain affected school attendance and sleep. Patients were absent from school on 21% of 3186 school days, with half of the absenteeisms on days with reported pain. Of the pain-associated absenteeisms, two-thirds occurred when pain was managed at home, and one-third when patients were hospitalized. The average consecutive number of school days missed was 2.7. These findings have implications for developmentally critical activities.

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This study was a 19-week prospective conducted to determine the effectiveness of a self-hypnosis/relaxation intervention to relieve symptoms of psychological distress and moderate immune system reactivity to examination stress in 35 first-year medical students. Twenty-one subjects were randomly selected for training in the use of self-hypnosis as a coping skill and were encouraged to practice regularly and to maintain daily diary records related to mood, sleep, physical symptoms, and frequency of relaxation practice. An additional 14 subjects received no explicit training in stress-reduction strategies, but completed similar daily diaries. Self-report psychosocial and symptom measures, as well as blood draws, were obtained at four time points: orientation, late semester, examination period, and postsemester recovery. It was found that significant increases in stress and fatigue occurred during the examination period, paralleled by increases in counts of B lymphocytes and activated T lymphocytes, PHA-induced and PWM-induced blastogenesis, and natural killer cell (NK) cytotoxicity. No immune decreases were observed. Subjects in the self-hypnosis condition reported significantly less distress and anxiety than their nonintervention counterparts, but the two groups did not differ with respect to immune function. Nevertheless, within the self-hypnosis group, the quality of the exercises (ie, relaxation ratings) predicted both the number of NK cells and NK activity. It was concluded that stress associated with academic demands affects immune function, but immune suppression is not inevitable. Practice of self-hypnosis reduces distress, without differential immune effects. However, individual responses to the self-hypnosis intervention appear to predict immune outcomes.

Traditionally, posthypnotic amnesia has been construed as a subjectively compelling deficit in memory retrieval. Alternatively, it may represent a motivated failure to utilize appropriate retrieval cues, lack of effort in recall, active suppression of memory, or unwillingness to verbalize the critical material. In an effort to test the alternative hypothesis of amnesia, 488 subjects were presented with four kinds of instructions designed to overcome the effects of suggested posthypnotic amnesia. The instructions particularly affected subjects of low and moderate hypnotizability who failed the criterion for amnesia. For those of moderate and high hypnotizability who met the criterion for amnesia, however, explicit requests for temporal organization, exhortations to maximize recall, and demands for honesty in reporting produced no greater effect on memory than did a simple retest. These results place some boundaries on both the traditional and alternative views of posthypnotic amnesia and invite further exploration of both cognitive and contextual models of the phenomenon.

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