Good review by DCRainmaker which basically replicates what we've all experienced. Can't add link for some reason but check out:-
This just started happening to me over the past 2 weeks. Have had the watch for a month now. Everytime I go on a run, within minutes the HR flatlines. I thought I left these problems behind with Fitbit lol guess not.
It's really quite ridiculous that I cant find a decent watch where the heart rate will be consistently monitored even while running. About to just buy a chest strap monitor 🤣
@lisafox16 - From DCR review, this probably sums the Galaxy Watch / Active up -
"Heart rate accuracy is an unmitigated mess. Pretty much the worst device I’ve seen in a long time, no matter the sport or app used."
Good lord it's painful to see how old this post is, and for me to have this problem still in April of 2019.
I'll be lucky if my Galaxy Watch obtains my heart rate for the first 5 mins of a walk (yes, a walk - low intensity, sweat free walk). I don't even know why I physically initiate a run on my Galaxy Watch because there's honestly little chance it'll trace. If I had to give an honest estimation, given my three most common types of exercises that I do (walk, outdoor run, outdoor bike), I would have to say my Galaxy Watch has been able to track my heart rate 25% of the time, otherwise I'm flatlining at what the watch last detected (e.g. a 40min run flatlined at 65bpm).
Let is be known that I wear my watch snug, as I hate dislike when my watch is flying around. Also, that I have tried it both tighter and looser to no avail. I have my heart rate sensor set to always on.
I was in the market for a watch that supported the basics of a smartwatch (Galaxy Watch was acceptable as its app selection is puke worthy, but it covered the basics), internal storage (Galaxy Watch has plenty enough, and supports Spotify - Bonus!), and had a reliable heart rate monitor (we all know my opinion on this by now).
I rarely had an issue with my Fitbit Charge 2 when it came to heart rate sensing, besides when I was drenched in sweat (that I can understand). I understand that this watch isn't labeled as a 'Fitness Tracker', but c'mon, heart rate sensing at this time is just a fundamental component. Especially when you have your own dedicated health app and are charging this much sweet $$$.
In summary, I am dissappointed with the product. The shotty heart rate sensor is a massive nail in the coffin for me. Even for the average, not overly fitness focused individual, this watch will fail for you, as a walk won't even provide you with a reliable heart rate tracing.
I'll be returning this Watch in a couple days and will continue shopping around! Open to suggestions!