I'm not sure the body battery/stress measures are that great. Garmin is infamous for having an awful sleep algo and it still has a lot of trouble detecting naps. It doesn't bode well for being able to get stress data. I think it's good for generally determining high stress vs low stress and when you've overdone exercise recently but probably not much more.
replyBody battery is amazing. I had long COVID/ME/CFS, and looking at the body battery when waking up was an outstanding predictor of how my day was going to be. When I hit 5% body battery, I was really feeling horrible.
replyIt's just a collation of sleep-end RHR/HRV. It's completely trivial and many manufacturers do this correctly; both are extremely reliable predictors of recovery metrics.
replyGarmin has absolutely shitty sleep tracking but it doesn't matter; any wearable more or less nowadays can get static heart rate correct, leading to more or less accurate recovery metrics.
"Collect every paper you can find on RHR/HRV/etc. recovery metrics. Develop an algorithm for predicting recovery score per day based on the research" as a prompt to a Codex or Claude agent can probably get you 98-100% of the way there.
If the algorithm is proprietary, how do you know it is calculating something meaningful?
replyYes, and the sleep tracking that adds or subtracts. While not super accurate, it's good enough for me.
replyHRV from optical is garbage-in garbage-out
replyand post-2020 Garmin has totally lost their way with development/algorithms