Circular tracks your breathing rate continuously but uses your nightly values to make an average that will be taken as an element of analysis for your day. 

Variation within a day is more impacted by activities. Measuring breathing rate throughout the day provides less insight than does measuring breathing rate during sleep. Since the need for oxygen is roughly constant during sleep period, you would expect breathing rate to be the same.

This metric varies much less than your resting heart rate and your HRV and is therefore much more stable. Breathing rate tracking becomes very useful when it increases a lot compared to your reference. This metric acts as a threshold that can warn you when something is highly unusual. The difference between your daily value and your Reference shows to what degree you are in good condition or not. 

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Normal values for a resting adult range from 12 to 18 breaths per minute. 

Breathing rate tracking has become more valuable with the recent events related to the covid 19 health crisis. Thanks to this metric and by correlating it with others, we could detect that a person had covid, 1 to 2 days prior to the onset of symptoms. Indeed breathing rate combined with SpO2 allows us to have an additional contributor to validate a sudden biometric changes and detect symptoms related to respiratory conditions. 

Respiration rates may increase with fever, illness, pain and other medical conditions but also with alcohol, prescription drugs and bad recovery for example, that’s why breathing rate is one of the many contributors to your energy score. 

If you want to read more about the energy score you can read the article about Understanding the Circular® Energy score: are you ready or not for the day? 

We remind you that the Circular™ ring is not a medical device and should not be used to diagnose or monitor a pathology.

Scientific sources: 

• Wearable technology: role in respiratory health and disease, Andrea Aliverti
• Characterizing Performance for Emerging Technologies. Kelley, Scott D. MD*; Ramsay, Michael A. E. MD, from the *Respiratory & Monitoring Solutions, Covidien, Mansfield, Massachusetts; and †Department of Anesthesiology and Pain Management, Baylor University Medical Center, Dallas, Texas.
  

• Recent development of respiratory rate measurement technologies. Haipeng Liu, John Allen, Dingchang Zheng and Fei Chen. Published 2 August 2019 Physiological Measurement, Volume 40, Number 7