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Reduced heart rate readings during activities

eeyou
over 1 year ago

Hi.

I've seen quite a few threads here regarding inaccurate hear rate readings, however, they don't seem to be describing exactly the weirdness that I'm observing.

General description: the watch (Venu 3, primary wearable) is reading way lower heart rate values during activities, when there is no activity being recorded on the watch.

What's happening: I do indoor cycling on Zwift using a smart trainer, I have Garmin HRM-DUAL heart rate chest strap paired with the trainer (this is where Zwift gets heart rate readings from), activity is recorded in Zwift and when finished riding Zwift exports the activity to Garmin Connect. Venu 3 is not used at all for the activity recording, it's just idling (in smartwatch mode). During the ride, the watch will consistently read far lower values than the values I see on Zwift from the chest strap.

For example, here's heart rate chart from an activity, that got imported from Zwift (i.e. readings from the chest strap):

And this is heart rate chart from day summary page on the day of the activity (i.e. readings from the watch):

Starts at ~88bpm, peaks at 111bpm and ends at 97bpm - way-way off from what the strap recorded. With sudden heart rate surge right after the activity...

Now, I can understand, that the watch probably has reduced sampling rate in "resting" mode (i.e. no activity being actively recorded) to save on the battery, so as an experiment I tried few times forcing the watch into "active" mode by recording simple "Cardio" workout at the same time as Zwift is recording the ride, and this results into matching data:

Heart rate from an activity from Zwift:

And from day summary page (obviously, some data aggregation happening here, but it's in the same ballpark):

I'm trying to understand whether there is any issue here with this heart rate discrepancy, could it lead to incorrect calculations of other metrics that rely on heart rate data...

I believe it does? For example, on the weeks when I do not use this "Cardio" workout "hack", I struggle to reach "intensity minutes" target. But doing the "hack" at least once easily fills the circle., and "vigorous minutes" are used in "fitness age" calculations...in fact, ever since I caved in and started Zwifting my fitness age value has returned to my real age (used to be 3-4 years lower). Wouldn't be surprised if VO2 Max estimations are also inadequate because of erroneous heart rate data...

I'm hesitant doing this "hack" all the time (even if immediately discarded when stopped recording), because now it could lead to sort of doubled amount of activity and throw calculations off again but to the other extremum?

Is there some setting I could tweak on the watch to have the watch realize I'm actually doing a workout so it needs to read heart rate more frequently without actually starting a workout on the watch?

  • 0 24 days ago

    I have been having an intermittent, but frequent’ issue with my Venu 3s heart rate measurement. Sometimes, the HR measurement is much lower than it should be. For example … starting from a resting HR of 63, when I sprint with maximum effort for 100 yds the Venu reads a HR of 89. I know this can’t be correct because when I measure my pulse I’m getting a HR between 135 and 145. Sometimes during the course of an extended activity, the HR measurement fluctuates dramatically, often decreasing with increased exertion. Over the past month, I have been developing all kinds of superstitious behaviors. Now, before I begin a measured activity, I turn the watch off, scrub my wrist with antibacterial soap, rinse thoroughly, dry, then rub 90% isopropanol on my toast, air dry, put on the watch, then cycle it on/ off 2 times. Clearly, this is superstitious, because over the month some of these actions correlated with correct performance of the watch. In all, this is very frustrating. I purchased the Venu because of Garmin’s overhyped depiction of the “amazing accuracy” of its HR measurements. Now I’m seeing this $350 purchase a complete waste of money. What is completely infuriating is that a $25 Chinese “fitness watch” I bought when I left my Venu home when I was on a 2-week business trip was more reliable. It may not  have been as accurate to the beat, but at least it was consistent over the period. 

  • 0 13 days ago in reply to 9168849

    I am the same. I have had enough of it. I need to do 1KM, then stop, reboot the watch and run the other 5KM of my run. The data from that is completely useless, and it destroys the rhythm of my runs.  It's been happening for ages now and with no fix incoming I am reluctantly changing brands.