I think my watch is wrong about some caloric burns

I was reading an article the other day that was a bit disheartening about how a lot of the common and popular sports watches are very very wrong about the caloric burn that it provides you with and this is especially true with the cheaper ones.

Mine is one of the cheaper ones.

in a clinical study that I read almost all of the watches were around 20% wrong and some of the worse misbehaving ones were up to 90% wrong in their calculations of how many calories you burn during a particular exercise.

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let's take pickleball doubles as a recent example. I played about 90 minutes and none of it was anywhere near as intense as my runs normally are yet the watch is telling me that this burns just as much if not more than running does.

I got quite sweaty while I was doing this but I wouldn't say that at any point I was out of breath and exhausted feeling the way that I am if I do 90 minutes of running, or in my case about 75 minutes because that is how long it takes for me to do a 10k or thereabouts.

My heart rate jumps up and down because of all the walking or even breaks that we take between matches and I rarely enter the anaerobic state at all.

That's just 54 seconds spent in anaerobic state whereas when I go running I spend almost all of my time in that category... Yet the watch tells me that I am burning about the same amount of calories regardless of which of these I decide to do.

Now I had read in the past that once you cross a certain BPM threshold it doesn't really matter and this is why they encourage people that are trying to lose weight to stay in zone 2 or 3 which would be "intensive" and "aerobic" state of BPM. If I do that while I am jogging my jog turns into a walk.

I mean I guess there is some science there even based on my own observations as far as "burn" is concerned over longer periods of time with less intensity but to me it just feels as though it couldn't possibly be true.

I'm not really trying to lose weight right now anyway but after casually playing pickleball and not really even feeling like it was remotely difficult and having my watch tell me it is the same exercise output as a run that actually is quite draining on me, just feels wrong.

In the study on the watches that I read it commented that these watches are only really reliable about two things: Steps and sleep tracking. I suppose the rest should just be treated as a list that reminds you how much or how little exercise you have gotten in the week, month, or year.

here's a good article with some science to it that can help you to work around the inaccuracies of your fitness band / smart watch.