Versa2 Heart Rate latency

[jbirchy]

What is the latency of the displayed heart rate to my actual heart rate on the Versa2?

I assume that there is some kind of running average algorithm going on.

It looks like 30 seconds because when I do interval training I see the HR on the watch keep going up even though I have slowed down, it then takes about 30 seconds to start ramping back down.  I see the same when increasing my workout.

[Guy_]

Hi @jbirchy -  it depends where you are looking, 30 seconds seems a bit long.

It could be if you are using a special clock face without seconds that updates are less regularly.

Try with a different clock face. There are many in the gallery. SimpleClockPro clock face has a pulsing heart rate readout which pulses for each new reading received in order to see if it is working.That might give you your answer.

[jbirchy]

Thanks, but I was using the spinning exercise function, nothing to do with a clock face.
And yes, 30s latency is very long, which is the problem.

[LZeeW]

Hello @jbirchy and welcome to the Community.  There is a true physiologic lag between the time that a pulse is generated from the heart to when it is detected at the wrist by an optical heart rate monitor (OHRM).  This time will vary from person to person and is only a part of what you are observing.  I think you are more interested in the latency of the OHRM itself.  Fitbit uses different configurations of emitters and sensors.  I'm sure Fitbit considers all this information to be proprietary and you won't get an answer to your question.  I can think of two places you can look for real world comparisons.  DC Rainmaker and The Quantifies Scientist do side by side reviews of many device brands.  You will need to do some searching, but you might find your answer.

And you are absolutely correct about your clock face comment.  A clock face or your heart rate as a real time stat are still taking that measurement at your wrist.

[jbirchy]

Thanks, yes Fitbit would definitely not share their algorithms, but I would like to know what they expect the OHRM latency to be.  I'm trying to track some anomalies between my breathing and my heart rate and with such a lag it's very difficult to evaluate.