Out of curiosity, what are you trying to track wrt respiratory rate? Like what behaviors would you be modifying based on respiratory rate?

I have trouble to keep breathing normally while I work. At the end of the day, my breath is usually shallow.

This is extremely difficult because you need something around your lungs/diaphragm or mouth/nose to accurately measure your breathing rate. Even with precise readings of your pulse, blood pressure, etc... you can’t even remotely calculate your breathing rate.

Not true. Respiration can be extracted from heart beat by beat interval data. Happens all the time in heart rate monitors.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5390977/

But you can't reliably get beat by beat interval data from a wrist PPG under normal living conditions. Also, to get breathing rate from beat intervals only really works when the parasympathetic nervous system is dominating, and isn't very observable in older people.

Very cool. I had no idea things had gotten that accurate. My grandpa was a cardio-thoracic surgeon so I always had a bit of hobbyist’s interest. Most of my reading materials were obviously a bit dated.

No worries. Wrist measurements are noisy and difficult, but there is a great deal of info to be extracted from heart rate data. Lots of teams, including Apple, are working to figure it out. The better the extraction of heart rate from the data, the more that can be done done with it. For example, there are groups using heart rate variability (HRV) characteristics to predict neonatal sepsis, a leading cause of death in infants.

https://pubmed.ncbi.nlm.nih.gov/31295130/ https://pubmed.ncbi.nlm.nih.gov/11134441/

That work is not with a watch of course, but it is extending the understanding of the relationships of HRV to other physiological issues. Good stuff.

AirPods could do it. AirPods could accurately take your temperature as well.

I'm hoping this will happen. I don't wear my AirPods continually, unlike my watch; but I do wear them daily, and pretty consistently while exercising.

Apple has a related patent from back in 2009. Physical size seems problematic for AirPods when you could use that space for more battery, but I could see this showing up in Power Beats Pro in the not too distant future.

https://www.patentlyapple.com/patently-apple/2009/04/apple-r...

> The sensor can also be other than (or in addition to) an activity sensor, such as a psychological or biometric sensors which could measure temperature, heartbeat, etc. of a user of the monitoring system. Since sensors can be positioned proximate to the head or ear of the user, useful psychological or biometric data can be acquired. The sensor can also be other than (or in addition to) an activity sensor, such as a global positioning system (GPS) receiver or a proximity sensor.

There's enough room to tinker with the dimensions that adding a temperature probe seems feasible. Like the stem of the Pros is actually shorter, which was clever because it means people know you have the fancy new ones. This couldn't add more than a few cubic millimeters.

Breath tracking is pure software, offloaded to the phone, opt-in to auto activate when in exercise mode.

I think we'll see both in the next few iterations, the fitness push is huge and the temperature monitoring would be timely. We'll see.

Even if it's physically possible in the standard AirPods, they might still put it in Power Beats for branding reasons, since those are the more fitness-focused headphones.

Then a year or two down the line, it could make its way down to regular AirPods if the size/cost isn't an issue.

Some Garmin watches offer a "breaths per minute" metric.

https://support.garmin.com/en-US/?faq=2yEgS0Pax53UDqUH7q4WC6

It doesn't work without a chest strap.

My VivoActive 4 tracks this without any external accessories. I've never really looked at the data and can't tell you how accurate it is though.

I have spent some time testing it, it is useless. Maybe it's accurate if you're not doing controlled breathing. I haven't had someone else watch me and compare. (I am also a trained vocalist and do a fair amount of yoga, it might be that it's only accurate for people with minimal breath training, or people with more exercise-focused breath training.)

I have a Garmin 245 that reports respiration without a chest strap. It tracks throughout the day. You can view on a line chart, or view awake/asleep averages. No idea how it measures, or if it’s accurate.

I've been testing this with and without the chest strap and it's not at all correct. I deliberately slow my breathing to 1-2 breaths per minute and it goes from saying 13 to 12. The metric is there, I don't trust it at all.

The whoop strap tracks breaths per min as well

I was excited for a minute thinking this was a strap for the Apple Watch that also tracks respiratory data.