This review article by Siobhan Banks and David F. Dinges examines the behavioral and physiological consequences of chronic sleep restriction. Adequate sleep is essential for overall health, and chronic sleep restriction can lead to a range of neurobehavioral deficits, including lapses in attention, reduced working memory, impaired cognitive throughput, and depressed mood. Neurobehavioral deficits accumulate over days of partial sleep loss, becoming equivalent to those caused by 1 to 3 nights of total sleep loss. Recent studies show that chronic sleep restriction to less than 7 hours per night can lead to significant daytime cognitive dysfunction comparable to severe acute total sleep deprivation. Individual variability in responses to sleep restriction appears stable, suggesting a trait-like vulnerability or compensatory changes in neurobiological systems involved in cognition. While the causal role of reduced sleep duration in adverse health outcomes remains unclear, laboratory studies have found that sleep restriction can negatively impact endocrine functions, metabolic responses, and inflammatory markers, indicating potential physiological consequences. The review also discusses the effects of sleep restriction on driving ability, immune responses, and cardiovascular health, highlighting the importance of adequate sleep duration (7-8 hours per night) for maintaining optimal health and preventing adverse outcomes.This review article by Siobhan Banks and David F. Dinges examines the behavioral and physiological consequences of chronic sleep restriction. Adequate sleep is essential for overall health, and chronic sleep restriction can lead to a range of neurobehavioral deficits, including lapses in attention, reduced working memory, impaired cognitive throughput, and depressed mood. Neurobehavioral deficits accumulate over days of partial sleep loss, becoming equivalent to those caused by 1 to 3 nights of total sleep loss. Recent studies show that chronic sleep restriction to less than 7 hours per night can lead to significant daytime cognitive dysfunction comparable to severe acute total sleep deprivation. Individual variability in responses to sleep restriction appears stable, suggesting a trait-like vulnerability or compensatory changes in neurobiological systems involved in cognition. While the causal role of reduced sleep duration in adverse health outcomes remains unclear, laboratory studies have found that sleep restriction can negatively impact endocrine functions, metabolic responses, and inflammatory markers, indicating potential physiological consequences. The review also discusses the effects of sleep restriction on driving ability, immune responses, and cardiovascular health, highlighting the importance of adequate sleep duration (7-8 hours per night) for maintaining optimal health and preventing adverse outcomes.