The Cumulative Cost of Additional Wakefulness: Dose-Response Effects on Neurobehavioral Functions and Sleep Physiology From Chronic Sleep Restriction and Total Sleep Deprivation
TL;DR: It appears that even relatively moderate sleep restriction can seriously impair waking neurobehavioral functions in healthy adults, and sleep debt is perhaps best understood as resulting in additional wakefulness that has a neurobiological "cost" which accumulates over time.
Abstract: OBJECTIVES: To inform the debate over whether human sleep can be chronically reduced without consequences, we conducted a dose-response chronic sleep restriction experiment in which waking neurobehavioral and sleep physiological functions were monitored and compared to those for total sleep deprivation. DESIGN: The chronic sleep restriction experiment involved randomization to one of three sleep doses (4 h, 6 h, or 8 h time in bed per night), which were maintained for 14 consecutive days. The total sleep deprivation experiment involved 3 nights without sleep (0 h time in bed). Each study also involved 3 baseline (pre-deprivation) days and 3 recovery days. SETTING: Both experiments were conducted under standardized laboratory conditions with continuous behavioral, physiological and medical monitoring. PARTICIPANTS: A total of n = 48 healthy adults (ages 21-38) participated in the experiments. INTERVENTIONS: Noctumal sleep periods were restricted to 8 h, 6 h or 4 h per day for 14 days, or to 0 h for 3 days. All other sleep was prohibited. RESULTS: Chronic restriction of sleep periods to 4 h or 6 h per night over 14 consecutive days resulted in significant cumulative, dose-dependent deficits in cognitive performance on all tasks. Subjective sleepiness ratings showed an acute response to sleep restriction but only small further increases on subsequent days, and did not significantly differentiate the 6 h and 4 h conditions. Polysomnographic variables and delta power in the non-REM sleep EEG-a putative marker of sleep homeostasis--displayed an acute response to sleep restriction with negligible further changes across the 14 restricted nights. Comparison of chronic sleep restriction to total sleep deprivation showed that the latter resulted in disproportionately large waking neurobehavioral and sleep delta power responses relative to how much sleep was lost. A statistical model revealed that, regardless of the mode of sleep deprivation, lapses in behavioral alertness were near-linearly related to the cumulative duration of wakefulness in excess of 15.84 h (s.e. 0.73 h). CONCLUSIONS: Since chronic restriction of sleep to 6 h or less per night produced cognitive performance deficits equivalent to up to 2 nights of total sleep deprivation, it appears that even relatively moderate sleep restriction can seriously impair waking neurobehavioral functions in healthy adults. Sleepiness ratings suggest that subjects were largely unaware of these increasing cognitive deficits, which may explain why the impact of chronic sleep restriction on waking cognitive functions is often assumed to be benign. Physiological sleep responses to chronic restriction did not mirror waking neurobehavioral responses, but cumulative wakefulness in excess of a 15.84 h predicted performance lapses across all four experimental conditions. This suggests that sleep debt is perhaps best understood as resulting in additional wakefulness that has a neurobiological "cost" which accumulates over time.
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TL;DR: These findings explain how various drugs affect sleep and wakefulness, and provide the basis for a wide range of environmental influences to shape wake–sleep cycles into the optimal pattern for survival.
Abstract: A series of findings over the past decade has begun to identify the brain circuitry and neurotransmitters that regulate our daily cycles of sleep and wakefulness. The latter depends on a network of cell groups that activate the thalamus and the cerebral cortex. A key switch in the hypothalamus shuts off this arousal system during sleep. Other hypothalamic neurons stabilize the switch, and their absence results in inappropriate switching of behavioural states, such as occurs in narcolepsy. These findings explain how various drugs affect sleep and wakefulness, and provide the basis for a wide range of environmental influences to shape wake-sleep cycles into the optimal pattern for survival.
2,295 citations
TL;DR: This paper reviews a novel hypothesis about the functions of slow wave sleep-the synaptic homeostasis hypothesis, which accounts for a large number of experimental facts, makes several specific predictions, and has implications for both sleep and mood disorders.
1,864 citations
TL;DR: Cognitive deficits believed to be a function of the severity of clinical sleep disturbance may be a product of genetic alleles associated with differential cognitive vulnerability to sleep loss.
Abstract: Deficits in daytime performance due to sleep loss are experienced universally and associated with a significant social, financial, and human cost. Microsleeps, sleep attacks, and lapses in cognition increase with sleep loss as a function of state instability. Sleep deprivation studies repeatedly show a variable (negative) impact on mood, cognitive performance, and motor function due to an increasing sleep propensity and destabilization of the wake state. Specific neurocognitive domains including executive attention, working memory, and divergent higher cognitive functions are particularly vulnerable to sleep loss. In humans, functional metabolic and neurophysiological studies demonstrate that neural systems involved in executive function (i.e., prefrontal cortex) are more susceptible to sleep deprivation in some individuals than others. Recent chronic partial sleep deprivation experiments, which more closely replicate sleep loss in society, demonstrate that profound neurocognitive deficits accumulate over time in the face of subjective adaptation to the sensation of sleepiness. Sleep deprivation associated with disease-related sleep fragmentation (i.e., sleep apnea and restless legs syndrome) also results in neurocognitive performance decrements similar to those seen in sleep restriction studies. Performance deficits associated with sleep disorders are often viewed as a simple function of disease severity; however, recent experiments suggest that individual vulnerability to sleep loss may play a more critical role than previously thought.
1,864 citations
TL;DR: Recent experiments reveal that following days of chronic restriction of sleep duration below 7 hours per night, significant daytime cognitive dysfunction accumulates to levels comparable to that found after severe acute total sleep deprivation.
Abstract: Adequate sleep is essential for general healthy functioning. This paper reviews recent research on the effects of chronic sleep restriction on neurobehavioral and physiological functioning and discusses implications for health and lifestyle. Restricting sleep below an individual's optimal time in bed (TIB) can cause a range of neurobehavioral deficits, including lapses of attention, slowed working memory, reduced cognitive throughput, depressed mood, and perseveration of thought. Neurobehavioral deficits accumulate across days of partial sleep loss to levels equivalent to those found after 1 to 3 nights of total sleep loss. Recent experiments reveal that following days of chronic restriction of sleep duration below 7 hours per night, significant daytime cognitive dysfunction accumulates to levels comparable to that found after severe acute total sleep deprivation. Additionally, individual variability in neurobehavioral responses to sleep restriction appears to be stable, suggesting a traitlike (possibly genetic) differential vulnerability or compensatory changes in the neurobiological systems involved in cognition. A causal role for reduced sleep duration in adverse health outcomes remains unclear, but laboratory studies of healthy adults subjected to sleep restriction have found adverse effects on endocrine functions, metabolic and inflammatory responses, suggesting that sleep restriction produces physiological consequences that may be unhealthy.
Citation:
Banks S; Dinges DF. Behavioral and physiological consequences of sleep restriction. J Clin Sleep Med 2007;3(5):519-528.
1,271 citations
TL;DR: The concept of sleep health synergizes with other health care agendas, such as empowering individuals and communities, improving population health, and reducing health care costs, and offers the field of sleep medicine new research and clinical opportunities.
Abstract: Good sleep is essential to good health. Yet for most of its history, sleep medicine has focused on the definition, identification, and treatment of sleep problems. Sleep health is a term that is infrequently used and even less frequently defined. It is time for us to change this. Indeed, pressures in the research, clinical, and regulatory environments require that we do so. The health of populations is increasingly defined by positive attributes such as wellness, performance, and adaptation, and not merely by the absence of disease. Sleep health can be defined in such terms. Empirical data demonstrate several dimensions of sleep that are related to health outcomes, and that can be measured with self-report and objective methods. One suggested definition of sleep health and a description of self-report items for measuring it are provided as examples. The concept of sleep health synergizes with other health care agendas, such as empowering individuals and communities, improving population health, and reducing health care costs. Promoting sleep health also offers the field of sleep medicine new research and clinical opportunities. In this sense, defining sleep health is vital not only to the health of populations and individuals, but also to the health of sleep medicine itself.
1,222 citations
References
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01 Jan 1968
11,993 citations
TL;DR: Techniques of recording, scoring, and doubtful records are carefully considered, and Recommendations for abbreviations, types of pictorial representation, order of polygraphic tracings are suggested.
Abstract: With the vast research interest in sleep and dreams that has developed in the past 15 years, there is increasing evidence of noncomparibility of scoring of nocturnal electroencephalograph-electroculograph records from different laboratories. In 1967 a special session on scoring criteria was held at the seventh annual meeting of the Association for the Psychophysiological Study of Sleep. Under the auspices of the UCLA Brain Information, an ad hoc committee composed of some of the most active current researchers was formed in 1967 to develop a terminology and scoring system for universal use. It is the results of the labors of this group that is now published under the imprimatur of the National Institutes of Health. The presentation is beautifully clear. Techniques of recording, scoring, and doubtful records are carefully considered. Recommendations for abbreviations, types of pictorial representation, order of polygraphic tracings are suggested.
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Journal Article•
TL;DR: Although the questionnaire appears to be valid, further evaluation using a wider subject population is required, as sleep habits are an important déterminant of peak time there are other contibutory factors, and these appear to be partly covered by the questionnaire.
Abstract: An English language self-assessment Morningness-Eveningness questionnaire is presented and evaluated against individual differences in the circadian vatiation of oral temperature 48 subjects falling into Morning, Evening and Intermediate type categories regularly took their temperature Circadian peak time were identified from the smoothed temperature curves of each subject Results showed that Morning types and a significantly earlier peak time than Evening types and tended to have a higher daytime temperature and lower post peak temperature The Intermediate type had temperatures between those of the other groups Although no significant differences in sleep lengths were found between the three types, Morning types retired and arose significantly earlier than Evening types Whilst these time significatly correlated with peak time, the questionnaire showed a higher peak time correlation Although sleep habits are an important determinant of peak time there are other contibutory factors, and these appear to be partly covered by the questionnaire Although the questionnaire appears to be valid, further evaluation using a wider subject population is required
4,758 citations
Book•
01 Jan 1989
TL;DR: Part 1: Normal Sleep and Its Variations; Part 2: Abnormal Sleep.
Abstract: 1. Normal Sleep and Its Variations History Of Sleep Physiology And Medicine Normal Human Sleep: An Overview Normal Ageing Daytime Sleepiness And Alertness Sleep Deprivation Phylogeny Of Sleep Regulation Mammalian Sleep 2. Sleep Mechanisms Brain Electrical Activity And Sensory Processing During Waking And Sleep States Brainstem Mechanisms Generating REM Sleep Basic Mechanisms Of Sleep-Wake States Control Of Motoneurons During Sleep 3. Physiology in Sleep Physiological Regulation in Sleep Cardiovascular Physiology: Central and Autonomic Regulation Cardiovascular Physiology: The Peripheral Circulation Respiratory Physiology: Central Neural Control Respiratory Physiology: Control of Ventilation Respiratory Physiology: Breathing in Normal Subjects Respiratory Physiology: Sleep at High Altitudes Host Defense Endocrine Physiology Gastrointestinal Physiology Temperature Regulation **Sleep-related Penile Erections 4. Chronobiology Introduction: Chronobiology Circadian Rhythms in Mammals: Formal Properties and Environmental Influences Anatomy and Physiology of the Mammalian Circadian System Molecular Genetic Basis for Mammalian Circadian System The Human Circadian Timing System and Sleep-Wake Regulation **Sleep Homeostasis and Models of Sleep Regulation Circadian Rhythms in Fatigue, Alertness and Performance Melatonin in the Regulations of Sleep & Circadian Rhythms 5. Pharmacology Hypnotics: Basic Mechanisms and Pharmacology Hypnotics: Efficacy and Adverse Effects Stimulants: Basic Mechanisms and Pharmacology Stimulants: Efficacy and Adverse Effects Drugs Which Disturb Sleep and Wakefulness 6. Psychobiology and Dreaming Approaches to the Study of Dream Content: Methods Measures
4,558 citations
TL;DR: Sleep debt has a harmful impact on carbohydrate metabolism and endocrine function similar to those seen in normal ageing and, therefore, sleep debt may increase the severity of age-related chronic disorders.
3,322 citations