Garmin 945 is capturing Respiration rate during Treadmill run, but not during outside run

It should work automatically. What Is the Respiration Rate Feature on My Garmin Device?

"NOTE: An HRM-Tri, HRM-Run, HRM-Pro, or HRM-Dual strap is required for all activity types with the exception of Breathwork or Yoga activity types. Activity movement impacts the ability to read heart rate variability using the optical heart rate sensor resulting in inaccurate respiration rate readings."

Are you using one of those HRM straps?

hmmm. when I run on the treadmill I use a chest strap that connects to my iFit machine. when I run outside I do not wear a chest strap. Now I wonder if the Garmin is picking up the chest strap inside and therefore getting respiration data...but outside with no strap, the Garmin is not getting respiration data

Easy way to check is to go to menu, sensors and accessories and see if you have a heart rate monitor paired to the 945. It has to be picking up the heart rate strap on some level, otherwise it shouldn't be picking up respiration rate. 

e7andy said:

"NOTE: An HRM-Tri, HRM-Run, HRM-Pro, or HRM-Dual strap is required for all activity types with the exception of Breathwork or Yoga activity types. Activity movement impacts the ability to read heart rate variability using the optical heart rate sensor resulting in inaccurate respiration rate readings."

I don't use any of those but I get a respiration rate graph in my post-activity file.  I think any external HRM is sufficient, not just the Garmin branded ones.

It could mean that during none activities it works without the heart rate strap. It was an explicit note about the HRM strap during activities.

I forgot to wear my HRM-Tri on my run yesterday and didn't get any respiration measurements. I compared it to one activity when I had the HRM-Tri and then I got respiration measurements.

I thought that's the way it worked as well but this thread prompted me to check.  On Sunday I forgot my external HRM and relied on the onboard OHR instead.  A "respiration rate" graph was present in my activity file but the data was not what I am used to seeing there (it's pretty flat).  Thus I looked at the little "?" mark hover-over and I got the above text which specifically says:

"Your compatible Garmin device tracks respiration using optical heart rate technology."

I interpret that to mean an external HRM isn't necessary.

well I cannot explain it. I ran a race on Saturday and got no respiration data. when I view the activity in connect.garmin website, the respiration graph is not there, and its not available from the drop-down menu. on the stats page the section for respiration is also not there.  I just ran on my treadmill and the respiration data was there after running....I was wearing a HR strap( not Garmin brand)

badbri said:

I interpret that to mean an external HRM isn't necessary.

Yes and no.  Refer to footnote #2

support.garmin.com/.../

Yes and no.  Refer to footnote #2

support.garmin.com/.../

That's in reference to the respiration widget whereas my text was from a more-relevant activity recording, but in any event, it's clear that's not correct.  In separate activities, I'm obtaining Respiration Rate data from both a non-Garmin external HRM (not listed there) as well as the onboard OHR.