Did you know that during your sleep, Oura tracks your nocturnal respiratory rate – the number of breaths you take each minute? This simple metric is one of our vital signs, but it can be easily overlooked. After all, how often do you think about breathing? Still, whether you’re checking out the effects of a new workout regimen or looking for markers of overall health, respiratory rate trends can yield fascinating data. In this article we’ll tell you how – and why – to track nocturnal respiratory rate trends with Oura.
Respiratory rate is a small portion of the overall picture of your health, but it can offer some fascinating insights into your wellbeing. So, how and why to track respiratory rate trends? What can you learn from them? In this blog you’ll learn:
Measuring respiratory rate in a clinical setting is as simple as it sounds: it’s just the number of times a person takes a breath within 60 seconds (usually measured by how often their chest rises and falls). At rest, a typical respiration for adults is between 12 and 20 breaths per minute.
Research settings can be trickier. Where a doctor might quickly observe a person’s rising and falling chest to check their vital signs, researchers who need to measure fluctuations during the course of sleep find this kind of observation more difficult.
A variety of measures, from devices attached to nasal passages to ones that monitor tissue changes, have been used in lab settings. In one study¹, researchers demonstrated that acoustic monitoring – counting respiratory rate based on audible breaths – could be complicated by something as innocuous as the lab’s forced-air warming system.
The Oura ring tracks your nocturnal respiratory rate optically, from your blood volume pulse. Generally speaking, respiratory rate can be tracked from blood volume pulse in two ways: from amplitude changes, and changes in the time between heartbeats. Breathing in accelerates the heart rate, breathing out decelerates it.
While you’re sleeping, the Oura ring’s infrared sensors take samples from the arteries and capillaries of your finger at the rate of 250 Hz. You don’t need to have any equipment that would disturb your sleep – wearing the ring is enough.
The samples the Oura ring collects indicate your inter-beat-interval (IBI), yielding data on heart rate, heart rate variability – and respiratory rate.
Oura Cloud shows your nocturnal average respiratory rate every day, and you can also follow up your weekly and monthly average respiratory rate trends. This allows you to find your established nocturnal respiratory rate baseline and track for possible changes in your nocturnal respiratory rate trends.
Before moving any further, a quick reminder: remember that respiratory rate, as all body signal metrics, is highly individual. So, as long as your nocturnal respiratory rate stays within the scale considered normal, don’t compare your values with others but with your own baseline.
With that out of the way, it seems that changes within an individual’s average nocturnal respiratory rate trends are typically quite small. This means that it’s relatively easy to point out exceptional values compared to your baseline. But what can these changes mean – why to track respiratory rate trends? Here’s a couple of examples.
When interpreting your respiratory rate trends data, you can look for insights into training and recovery. Tracking changes in your respiratory rate trends can be way to follow up the efficacy of, for example, a new training plan, stress reduction technique or sleep pattern over the long term. Coupling these insights with other metrics, such as heart rate variability (HRV) and your Readiness Score, will give you a thorough outlook into your readiness status.
On the other hand, your average respiratory rate can jump temporarily up when you have a cold, for example. Moreover, it can stay relatively high for some time after the actual symptoms have disappeared, meaning that your body is still recovering from the illness.
Example of a daily respiratory rate trend in Oura Cloud. Monday 18 marks a return to normal levels after a cold.
It seems that women have more variability in their average respiratory rate than men, as respiratory rate tends to correlate with the stage of menstrual cycle.
If your average nocturnal respiratory rate baseline is high or low compared to the values considered normal (12–20 breaths per minute), we recommend to consult your physician. The same applies to situations where you’re making changes to your exercise routines, medication and nutrition, and have a known illness, or if you don’t feel well. Indirect (optical) tracking of respiratory rate via blood volume pulse has limitations in that it cannot be used during special conditions such as heavy snoring, episodes of sleep apnea or arrhythmia. In case of OSA (Obstructive Sleep Apnea), measuring must be made via oxygen saturation and nasal airflow tracking.
If you’re interested in tracking your nocturnal respiratory rate and other readiness metrics, and you don’t yet have the tools for it, have a look at the new Oura ring in Oura Shop. If you have an Oura ring, you can also dig deep into your respiratory rate trends in the Oura Cloud.
¹Yabuki, Shizuha & Toyama, Hiroaki & Takei, Yusuke & Wagatsuma, Toshihiro & Yabuki, Hiroshi & Yamauchi, Masanori. (2017). Influences of environmental noise level and respiration rate on the accuracy of acoustic respiration rate monitoring. Journal of Clinical Monitoring and Computing. DOI: 10.1007/s10877-017-9997-y.