The respiratory rate (RR) is the number of breaths a person takes per minute and is a fundamental marker of health. While awake, RR is influenced by movement, emotion, and conscious control. Monitoring RR during sleep provides an unbiased view of how the body regulates its involuntary functions. Breathing during rest is controlled entirely by the autonomic nervous system, making the sleep respiratory rate a sensitive indicator of underlying physiological changes. Technology now allows for continuous, non-invasive tracking of this vital sign.
Understanding Normal Respiratory Rate During Sleep
For a healthy adult, the typical respiratory rate while at rest during the day is between 12 and 20 breaths per minute. When sleep begins, the rate slows down, and most healthy adults maintain this range throughout the night. This rate is not static, however, as it fluctuates naturally while cycling through the different phases of sleep.
During Non-Rapid Eye Movement (NREM) sleep, especially the deep slow-wave stages, breathing becomes slow, deep, and rhythmic. This stability reflects the body’s decreased metabolic demand, reaching the slowest and steadiest rate of the night. The breathing pattern changes noticeably during Rapid Eye Movement (REM) sleep, characterized by heightened brain activity and vivid dreaming. In this stage, breathing becomes faster, more shallow, and irregular, often mirroring the erratic nature of the dream state.
Methods for Tracking Sleep Respiration
The most accurate method for measuring sleep respiration is Polysomnography (PSG), a clinical test often performed in a sleep lab. PSG uses specialized sensors, such as chest and abdominal belts, to measure respiratory effort and airflow. This technology provides detailed data and is considered the gold standard for diagnosing sleep-related breathing disorders. However, this method requires a prescription and is not intended for routine nightly monitoring.
Consumer-grade devices have made continuous tracking widely accessible outside of a clinic. Wearables like smart rings and watches use photoplethysmography (PPG) to measure changes in blood volume, which correlates with breathing patterns. Other consumer devices, such as under-mattress mats, use pressure or movement sensors to detect the rise and fall of the chest and abdomen. These devices are useful for tracking long-term trends and establishing a personal baseline, but they should be viewed as wellness tools rather than diagnostic instruments.
What Deviations in Respiratory Rate Can Indicate
A sustained deviation from the normal range signals that the body is under stress or experiencing a health issue. A consistently high respiratory rate, known as tachypnea, reflects an increased physiological demand. This elevation can be linked to conditions such as fever, infection, underlying lung issues like asthma or chronic obstructive pulmonary disease, or cardiovascular strain. Anxiety or a high-stress state can also lead to persistently rapid and shallow breathing patterns during sleep.
Conversely, a sustained low respiratory rate, called bradypnea, may indicate a different set of concerns. This reduced rate can be a side effect of certain medications, particularly central nervous system depressants like opioids or sedatives. A persistently low rate can also signal an issue with the central control of breathing, potentially related to neurological conditions or specific forms of sleep apnea.
The most common deviation is significant variability, where the rate frequently spikes and drops throughout the night. Highly irregular breathing patterns, including pauses, are the hallmark of sleep-disordered breathing. An apnea is a complete cessation of airflow, while a hypopnea is a significant reduction in airflow, both lasting for several seconds. These events cause the body to briefly wake up to resume breathing, resulting in a sudden spike in the respiratory rate after the pause. If a consistent pattern of abnormally high or low rates, or frequent breathing pauses, is noted, consult a healthcare provider for evaluation.