The respiratory rate, or the number of breaths taken per minute, naturally adjusts as the body transitions from wakefulness to sleep. This change reflects the body’s shift toward a state of rest and reduced metabolic demand. During sleep, the respiratory system is under the primary control of the brain’s automatic centers, leading to a pattern that is typically slower and more consistent than when a person is awake. Monitoring this physiological rate serves as an indicator of general health.
Defining the Normal Range
A healthy adult’s respiratory rate while at rest during the day is typically measured between 12 and 20 breaths per minute. Once sleep begins, this rate usually decreases slightly, remaining within the 12–20 breaths per minute window. This subtle reduction reflects the body’s decreased need for oxygen and lower production of carbon dioxide. The most significant factor influencing this baseline rate is a person’s age.
Children and infants have dramatically faster respiratory rates than adults, and their normal range decreases progressively as they grow older. For instance, a newborn infant’s rate can range from 30 to 60 breaths per minute. This rate stabilizes in toddlers, falling to 24 to 40 breaths per minute, and continues to decline through the school-age years until adolescence, when it approximates the adult range.
How Breathing Changes During Sleep Cycles
The breathing pattern during the night changes dynamically as the body cycles through the different stages of sleep. The sleep cycle is divided into Non-Rapid Eye Movement (NREM) sleep and Rapid Eye Movement (REM) sleep, each imposing unique demands on respiration.
During the deeper stages of NREM sleep, breathing becomes highly regular, rhythmic, and slow, representing the most stable pattern of the night. This phase is associated with a slight reduction in overall minute ventilation. This stability is primarily controlled by the brainstem’s respiratory center, which is highly sensitive to the concentration of carbon dioxide in the blood. When breathing is slow and regular, the body maintains a steady, slightly elevated level of carbon dioxide compared to wakefulness.
As the sleep cycle progresses, the body enters REM sleep, characterized by intense brain activity and muscle atonia, or temporary paralysis. During REM sleep, the breathing pattern becomes notably irregular, faster, and shallower. The muscle paralysis affects the accessory respiratory muscles, leaving the diaphragm as the primary muscle for ventilation. This loss of muscle tone increases resistance in the upper airway, leading to greater variability in the depth and frequency of breaths. The control system also becomes less responsive to chemical signals, resulting in a more chaotic pattern.
Recognizing Signs of Concern
While natural fluctuations occur throughout the night, certain patterns and rates signal potential underlying health issues. A persistently slow breathing rate, medically termed bradypnea, is defined as fewer than 12 breaths per minute in an adult. Conversely, a consistently fast rate, known as tachypnea, is classified as exceeding 20 breaths per minute while at rest. Both of these deviations can indicate problems ranging from medication side effects to respiratory distress or metabolic disorders.
A particularly concerning abnormal pattern is sleep apnea, which involves repeated pauses in breathing, or apneas, that last for 10 seconds or longer. Obstructive sleep apnea occurs when the airway physically collapses due to muscle relaxation. Central sleep apnea, a less common form, happens when the brain temporarily fails to send the necessary signals to the breathing muscles.
Another significant deviation is periodic breathing, such as Cheyne-Stokes respiration. This is characterized by a cyclical pattern of progressively deeper and faster breathing followed by a temporary decrease in rate or a complete pause. If a person’s partner observes frequent pauses in breathing, loud snoring, gasping, or choking during the night, or if the individual experiences excessive daytime sleepiness, these signs warrant consultation with a healthcare provider.