I have been using a Garmin Vivosmart since the end of November last year. I was looking at the long term data and was very pleased to see my high heart rate levels are steadily dropping. It's only about 2bpm per month which isn't a lot but I'm happy with the overall trend. Day to day it often feels like nothing is changing but this is a positive thing to see.
Discussion on the Heart Rate Monitor Factsheet by the Workwell Foundation can be found here: https://www.s4me.info/threads/heart-rate-monitor-factsheet-workwell-foundation.19443/
My mom-in-law over the weekend found an article that suggested the 0.6(220-age) formula was out-of-date, and that the current guideline was to add 15 points to one's resting heart rate. I'll ask her if she can give me the article citation for that.
In our HRM pacing FB group PwME & LC tend to use 220 - age x 55% or 50% for the more severely affected. But also RHR plus 10 - 15. It's very helpful to keep brief records of physical, cognitive, social and emotional activity, along with any stressors such as allergies, sensitivities, hormonal fluctuations, infections etc. This along with HR data can help with identifying patterns and the impact of changing activity levels Short Factsheet from Workwell on HRM (pdf) https://workwellfoundation.org/wp-content/uploads/2023/01/HRM-Factsheet.pdf Significant changes in HR in response to positional changes may be an indicator of dysregulation of the Autonomic Nervous System, which may manifest as POTS, orthostatic hypotension etc.
This is a little off topic for this thread, but I'm currently doing a 9-day home cardiac test because my last sleep study showed my average heart rate for the 2-day sleep study test was 30 and 31, considered too low for a nocturnal HR. My HR is normal during the day. I've been much more fatigued lately, which could make sense if my heart isn't beating fast enough during sleep to keep me properly oxygenated.