Respiratory rate is one of the most stable physiological metrics you can monitor during sleep. Understanding what it means, what's normal for you, and why changes matter can help you make smarter decisions about your health and recovery.
What is respiratory rate?
Respiratory rate, reported in respirations (breaths) per minute (rpm), typically ranges from 12 to 20 rpm at rest. Each respiration has two phases: Inhalation and exhalation. During inhalation, oxygen is brought into the lungs and transported throughout the body via the bloodstream. During exhalation, carbon dioxide is eliminated.
What is a normal respiratory rate during sleep?
A normal respiratory rate for healthy adults typically ranges from twelve to twenty breaths per minute. During sleep, this number can drop slightly as your body rests and recovers. What matters most is understanding your personal baseline, not comparing your number to a universal standard.
Normal respiratory rate fluctuation and why we measure it during sleep
In a healthy individual, daily respiratory rate fluctuates based on oxygen demand. When you exercise, you breathe harder and faster because your need for energy and oxygen is higher during intense physical strain. Because activity level creates more variation than changes in efficiency, measuring respiratory rate during sleep provides better insight into your body's baseline function.
Your need for oxygen is roughly constant from night to night, assuming air quality remains the same. When you see a sudden increase in sleeping respiratory rate, it likely reflects changes to respiratory efficiency rather than energy demand.
How does WHOOP measure respiratory rate?
WHOOP became the first wrist-worn wearable device to validate the accuracy of respiratory rate measurement during sleep. In a third-party study published in the Journal of Clinical Sleep Medicine, WHOOP respiratory rate was shown to be within one breath per minute of gold-standard truth. WHOOP reports the median respiratory rate during sleep.
We calculate respiratory rate from heart rate data by taking advantage of a phenomenon known as respiratory sinus arrhythmia. When you breathe in, your heart rate increases. When you breathe out, your heart rate decreases.
This allows blood to preferentially pass by the lungs while they are full of oxygen. Because your autonomic nervous system creates this cyclical increase and decrease pattern, we can identify respiratory rate in continuous heart rate data.
Take for example 25 seconds of heart rate data—you can see that the heart rate cycles up and down about every 5 seconds, corresponding to a respiratory rate of about 12 breaths per minute.
Why measuring respiratory rate matters
While respiratory rate indicates cardiovascular fitness and load, it is also remarkably stable. From night to night, you should not expect much change in your median respiratory rate. When it does change, that change tends to be meaningful.
In statistics, this is known as signal-to-noise ratio. It helps determine how much change you need to confidently conclude that a change is meaningful and not random variation. Median respiratory rate has a remarkably high signal-to-noise ratio, making it easy to interpret and trust.
What an elevated respiratory rate means
An elevated respiratory rate indicates that your body is experiencing additional stress. This can be caused by sleeping in a hot environment, traveling to a higher altitude, or recovering from intense physical strain. When your respiratory rate jumps significantly above your baseline, your body is working overtime to maintain oxygen levels and support recovery.
Take for example, the resting respiratory rate data of one WHOOP member, shown here with the member's permission, as they came down with the coronavirus. This WHOOP member was exposed to COVID-19 on March 7th and began experiencing symptoms on March 11th. During the 10 days before they became sick, respiratory rate varied only from a low of 15.4 rpm to a high of 16.1 rpm.
Compare this to the 11th through 13th where respiratory rate shot up to over 18.1 rpm. While in absolute numbers this increase might not seem huge, when ordinarily stable baselines suddenly jump up over 17%, something significant is happening.
To view your long-term respiratory rate trends, open the WHOOP mobile app and access the Health Monitor or tap the Sleep Dial from the Homescreen to view your Sleep Details.
It's worth noting that it doesn't take a deadly pandemic to increase respiratory rate. I took a handful of overnight flights, and some of my personal highest respiratory rates happened when sleeping on an airplane. Traveling from low to high altitude can also cause an elevated respiratory rate that resolves upon return to lower altitude.
When respiratory rate is elevated due to sleeping on a plane with stale, dry air or at altitude with lower oxygen content, that's a response to the environment and not necessarily cause for concern.
How illness impacts your respiratory rate
When you are fighting off an illness, particularly a lower respiratory tract infection, your body's demand for oxygen changes. If an infection impacts your lungs, each breath becomes less efficient. Lower respiratory tract infections take root below the larynx and are commonly associated with coughing, fatigue, and shortness of breath.
In a viral lower respiratory tract infection, the virus enters through the nose, mouth, or eyes and travels down the respiratory tract. The virus infects the alveoli, which are the blood/lungs interface where oxygen passes from the lungs to the blood and carbon dioxide passes from the blood to the lungs. Without functioning alveoli, each respiration does not remove as much carbon dioxide or provide as much oxygen to the blood.
To make up for the loss of efficiency per breath, the body is forced to undergo more respirations to provide the same oxygen supply. Monitoring your respiratory rate during sleep can serve as an early warning sign that your body is fighting something off. This allows you to prioritize rest and recovery.
Frequently asked questions about respiratory rate during sleep
Is sleep apnea linked to a high respiratory rate?
A low respiratory rate during sleep can sometimes be a sign of underlying health conditions, including sleep apnea. Conversely, a high respiratory rate may be caused by factors like anxiety, respiratory infections, or chronic lung conditions. If you consistently see abnormal numbers, consult a medical professional.
What is the ideal respiratory rate by age?
For most adults, a normal resting respiratory rate is between twelve and twenty breaths per minute. Children and infants naturally have higher respiratory rates. As you age, your baseline remains relatively stable, making it a reliable metric for long-term health monitoring.
Is 9 breaths per minute too low?
While twelve to twenty breaths per minute is the average for adults, some individuals—particularly highly trained endurance athletes—may have a resting respiratory rate below twelve. If your baseline is consistently around nine breaths per minute and you feel healthy, it may be normal for you. However, sudden drops below your established baseline warrant attention.
WHOOP is not a medical device, our products and services are not intended to diagnose COVID-19, the flu or any other disease, and should not be used as a substitute for professional medical advice, diagnosis or treatment.