Respiratory Physiology During Sleep

The respiratory system provides continuous homeostasis of partial pressures of arterial oxygen, carbon dioxide, and pH levels during constantly changing physiologic conditions. During wakefulness, volitional influences can override this automatic control. Modifications occur in the regulation and control of respiration with the onset of sleep. Consequences of these alterations of respiratory control can result in the pathogenesis of sleep-related breathing disorders and limit the usual respiratory compensatory changes to specific disease states. This article reviews the normal physiology of respiration in both awake and sleep states, and discusses the effects of common disease processes and medications on the respiratory physiology during sleep.