Heart rate often much lower than actually is during exercise

[Yorsh]

Sometimes it seems to get stuck around 110, when the machine I'm on gives me a much more realistic 150. It hovers around 110 for a while before slowly rising and catching up with the machine. This can take 30 seconds.

It only happens half the time, and even happens when I'm on a bike, barely moving my arms. I've tried tightening it during exercise, and wearing it on inner arm to avoid hair. Still happens.

Anyone else have this problem? Might exchanging it for another one help?

Thanks!

[Zoni68]

I have the same problem, but mine doesn’t catch up, it is consistently 20-50 bpm too low. Only once I got accurate readings, but it only lasted about a minute. 

[Yorsh]

Definitely sounds like you need a replacement. Does it happen even when on a machine that doesn't involve much arm movement like a bike?

Can anyone who doesn't have this problem tell me how they wear it during exercise?

[Zoni68]

Forgot to mention: the inaccuracy only seems to be a problem during exercise; my resting hr seems about right

[Zoni68]

Yes, today I tried it on a treadmill. My arms were stationary since they were gripping the hr monitor bar in front