Wolff-Parkinson-White (WPW) syndrome erratic HB readings

[sobe001]

Luxe reads ~130 bpm (instead of ~85) during level outdoor walk at 16 minute mile pace, but it reads correctly (~115) during higher intensity treadmill session at 14 minute mile pace and incline of 7. I've tried different wrist positions and wristband fits, and updating software. Can this be caused by unusual EKG of WPW user?

[Odyssey13]

Hi @sobe001  your health care professional would be the best one to ask about this. Fitbit isn't a medical device and I'm sure they didn't do beta tests with many people with WPW. Changing bands or updating software probably wouldn't change the readings. Have you checked your results with the Fitbit to what the doctor's office has your heart rate as during an office visit?

[sobe001]

Thanks for your comments Odyssey. I’ll be asking my cardiologist about this during my next scheduled visit. The curious thing is the Luxe does track closely, across a range of values, with my cardiologist-verified blood pressure device, as well as with the pulse readings from two different branded pairs of stationary bicycles and treadmills. It even seems to give accurate readings during outdoor walks at slower paces, but invariably goes haywire at a slightly faster pace.

[Odyssey13]

@sobe001  the Luxe has a firmware update. Have you received notice on your app for it? Maybe that would make a difference.

[sobe001]

Yes thx I applied it 2 or 3 days ago.

[LZeeW · Accepted solution]

@sobe001   WPW is diagnosed on an ECG.  Your Luxe uses the optical heart rate monitor (green LEDs) to measure heart rate.  It looks for pulsations in tiny blood vessels under the skin.  So if you and I were side by side on a treadmill with a 115 bpm heart rate, the Luxe has no way of "knowing" that you have WPW and I don't.  That being said, many independent reviewers say that LED heart rate monitors are less accurate at faster heart rates, but they can over count or under count.  If your stationary bike or treadmill measure heart rate with your hands on metal grips, then they are using an ECG to collect the data.  The heart rate from those machines is likely more accurate than a Fitbit measurement.

People with WPW can have episodes of very, very fast heart rates.  My background is physiology and biomedical engineering.  Please feel free to discuss anything with your cardiologist.  But it's my opinion that, if you're not having an episode, any erratic reading is part of LED limitations.  As a reminder, Fitbit recommends wearing your Fitbit three finger widths away from your bony bone on your wrist when exercising.  One finger width during normal wear.

[sobe001]

Thank you so much, LZeeW, for taking time to respond and for your very helpful descriptions of the different pulse measuring technologies, electromagnetic and optical. It leads me to speculate about a logical reason why Luxe readings are erroneously high at faster walking paces outdoors while they are accurate throughout an even wider range of paces on a treadmill or stationary bike. I suspect the fact that, on the indoor equipment, my hands firmly grab the handles with the metal detectors and this allows the Luxe to obtain more reliable readings than when my hands are not as stable outdoors (especially at higher paces). And, by the way, I have tried positioning the Luxe higher on my wrist as noted in their instructions and in your message.

In any event, I originally got the Luxe to monitor my heart rate outdoors in order to maintain an optimum Zone 2 rate for aerobic cardio, but it's proving itself inadequate for that purpose (as well as redundant on indoors equipment). I do like many of its other features and feel it provides a certain amount of value. Thank you again for your much appreciated feedback!