Inaccurate HR during weight training and HIIT

[samulrich]

I upgraded from a Change 5 to the Sense 2 and the short-term HR accuracy is horrible. Am I doing something wrong? Any tricks to improve?

The Charge 5 wasn't perfect but still measured my HR averaging around 125 (which is actually low for my weight training  - more precise measurements put it in low 130s) which was fine with me. The sense 2 on the exact same schedule at the same time will show an average of 90. 

It works great for long-term HR tracking like running, biking, elliptical but short-term is just so bad. 

[NatomCZ]

Exactly the same experience here. I train kettlebell swings and get ups, Sense 1 used to measure my HR max during these exercises somewhere around 160..170 bpm. Sense 2 measures max as 106 bpm with average at 85 bpm. Total nonsense. No active zone minutes.

[JerryHam]

Interesting results. I guess it completely depends on the type of workout or something. I find Sense 1 and Sense 2 to be almost exactly the same (both very bad) but in the other direction. They usually show well over what they should for me. Sometimes even 100% over. I end up getting Active Zone Minutes like crazy that I should not be getting because it reads so high. But I am doing running, jogging, and power walking. I don't usually bother looking at what FitBit says for my resistance training. I think this will be my last FitBit as the bad data is just so useless. Too bad as I have been using them for many years.

[NatomCZ]

Thanks @Dopovo for posting the link to the Quantified Scientist's accuracy analysis. That really does not look well - the results seem to be quite disappointing (especially for a new iteration of a premium device)  😕

[Jerseycitysteve]

Thanks. Fitbit must know but the company is silent.