Heart Rate lagging while exercising

[CindiLi]

I recently upgraded from my Inspire HR to the Versa 2 and am finding the Versa 2 is lagging in registering my HR while I am exercising.  Today I wore them both (for comparison after noticing this).  When I am walking up a steep hill where I am breathing heavily the Inspire HR will, I think quite accurately show my HR at around 135, the Versa 2 shows it as around 100.  Once I get to the top of the hill and am on level ground the Versa 2 will finally show it in the cardio zone around 130-135.  Then as I’m walking on level ground again at a decent pace they both show about 105 or so.  This happened today on all 4 hills I climbed.  

Is this a recent firmware issue or should I return my Versa 2 for another one and assume its faulty?

I have a fingers width between my band and arm which is my “normal” wearing style when exercising so it is not too loose or too tight.

[barnowl28]

This exact same thing is happening to me with my Versa Lite. Hiking up a steep hill, it was registering me at 108 when I clearly know it was closer to 130-135. After 58 mins of moderate hiking, I only got 27 "active zone minutes." If anyone has any tips for fixing the accuracy of the heart rate monitor, besides all the obvious troubleshooting instructions, please share. 

[CindiLi]

I am surprised I haven't heard from anyone at FitBit here.  So I just got off the elliptical which I did for 40 minutes.  I go at a decent pace on an interval program where normally my HR is in the 130-135 range.  First it showed my HR at 93 at 4 minutes in, then when I took a sip of water at 5 minutes it went up to 123 while I was standing there.  It was kinda all over the ball park for the next 5 minutes and then when I stopped to take another sip of water it showed 34 BPM!!  I think I'm dying lol.  I don't know if its just mine but I will be returning it for an exchange at Costco.  I have my fingers crossed that I have a faulty one and this isn't a problem for many of them.

[MrsGray75]

Hi, my new versa 2 is doing this as well. Working out and showing low heart rates when I’m sweating and know my bpm is up, then increasing when I’m just stood there. Today it is registering my resting bpm at 78! Hardly registering any fat burning when exercising when I know I’m in the fat burning zones from when I had my Alta HR!