Are you an endurance athlete?

I was surprised at how quickly my rhr came down after I started cycling more even though I've never been very active in my life.

It also (I think!) helped with my sleep apnea/general sleep problems, and I've always assumed a good bit of that was literally just being better at breathing.

An average of 60-70 according to watch.

Unless you're an elite marathon runner or something in this vein I think having a resting HR of 39 isn't the flex you think it is.

You're either humble bragging or you need to ask a few questions to your doctor