The respiratory rate is a measure of a person’s overall health. For a healthy adult, a sleep breathing rate of nine breaths per minute (BPM) falls at the lower edge of what is typically considered a normal range. While the accepted average for adults is higher, a consistently low rate of 9 BPM can be natural for some individuals, particularly during deep rest. The context of this rate—such as fitness level, age, and medications—determines whether it is a sign of optimal rest or a potential concern.
Defining Normal Sleep Breathing Rates
The respiratory rate naturally decreases when the body is at rest, reflecting lower energy demands during sleep. For most healthy adults, the average respiratory rate while awake is between 12 and 20 BPM. During sleep, the rate usually stabilizes within this range, though some sources suggest a slightly lower average.
A breathing rate consistently below 12 BPM is medically categorized as bradypnea, or abnormally slow breathing. However, 9 BPM does not automatically signal a problem. A healthy person’s rate fluctuates, but a consistent average of 9 BPM places it on the low end of the normal spectrum for sleep.
The Mechanics of Slowed Respiration During Sleep
The slowdown in breathing rate during sleep results from a shift in the autonomic nervous system. As a person transitions to sleep, the parasympathetic nervous system gains dominance, initiating a relaxation response and decreasing metabolic activity.
Reduced metabolic activity means the body consumes less oxygen and produces less carbon dioxide. Since the brain’s respiratory control centers are sensitive to carbon dioxide levels, this lower demand signals the brain to decrease the frequency of breaths. The result is a steady, rhythmic, and shallower pattern of breathing that supports rest and recovery.
Individual Factors That Influence Breathing Rate
The specific rate of 9 BPM is heavily influenced by the individual’s physical state and the current sleep stage. Breathing patterns are not uniform throughout the night, differing between non-rapid eye movement (NREM) and rapid eye movement (REM) sleep.
During NREM sleep, particularly in the deep, slow-wave stages, breathing slows to its most consistent and lowest rate, making 9 BPM most likely to be recorded then. Conversely, during REM sleep, when brain activity increases due to dreaming, breathing can become more irregular, erratic, and sometimes faster or shallower.
A person’s physical conditioning is another factor. Highly trained athletes often have a significantly lower resting metabolic rate, and for them, a sleeping rate of 9 BPM may be completely normal, reflecting highly efficient cardiovascular and respiratory systems. Age also plays a role; infants and children have much higher baseline rates, while older adults may experience slightly more variable or lower rates than younger adults.
Certain substances and medications can artificially suppress the respiratory rate. Alcohol, sedatives, and opioid pain medications are central nervous system depressants that reduce the respiratory drive. Using these substances before bed can push the average breathing rate lower than the natural baseline, potentially resulting in readings around 9 BPM or less.
Recognizing Concerning Breathing Patterns
While 9 BPM may be acceptable for a healthy, deeply sleeping individual, a persistently low rate accompanied by other symptoms can indicate an underlying health issue. The primary concern is not the number itself but whether that rate effectively maintains proper oxygen levels.
Worrying signs include excessive pauses in breathing, known as sleep apnea, or noticeable gasping, choking, or labored breathing during the night. Other indicators of insufficient nighttime respiration are persistent symptoms like morning headaches, excessive daytime fatigue, or a bed partner noticing blue or grayish discoloration of the lips or nail beds.
Conditions such as obstructive sleep apnea, central sleep apnea, or central hypoventilation can all lead to an abnormally slow or irregular breathing pattern. If a low rate is accompanied by any of these concerning symptoms, consulting a healthcare professional is necessary.