Charge 5 HR inaccurate when exercising

[DudleyM]

I recently upgraded to Charge 5 from Charge 4.  I have been consistently experiencing this issue – when doing aerobic exercise such as spinning, it fails to show the proper HR for the first 10-15 min.  I know it because I also use a chest strap HR monitor.  While the chest strap HR shows 130-150 beats/min, Charge 5, at least for the first 10 min, is stubbornly around 60-70. Then it quickly adjusts and suddenly it matches the chest strap monitor.

I did not have this issue with my older Charge 4. Any advice? Thank you.

[DavideFitbit]

Hi, I appreciate all the information that you've shared about the inconvenience that you've been experiencing with your Charge 5, @DudleyM.  

Before considering other options, I recommend that you try restarting the device using the three pulse restart method mentioned here below, instead of the restart option found on the Charge 5 itself: 

1. Connect your device to the charging cable. For instructions, see How do I charge my Fitbit device?
2. Press the button located on the flat end of the charger 3 times, pausing for 1 second between presses. Then wait 10 seconds or until the Fitbit logo appears.

In addition, please follow the instructions in this article to improve the accuracy of heart rate information and check the information mentioned here about other factors that could affect your heart rate reading, this has been useful to other users who have experienced something similar. 

I'll be around. 

[ssond]

I'm having exactly same problem as Dudley and others have reported.  When exercising, Charge 3 nearly matches my polar chest strap, new Charge 5 almost never gets over 100 BPM (while actual HR is near 150 as measured by polar, double checked with fingers on wrist).  Sounds like a product defect, no?

[SunsetRunner]

@DudleyM it's a long shot but maybe the reading might be affected by skin sweating (and hence helping the HR to become more accurate). I'm saying this because when running in summer (now it's cold and I became a couch potato) I experience the opposite phenomenon but our skins might react differently.

@ssond could you try to fasten your band a lilttle more than what you were used to do with Charge 4? I've never used a Charge 5 but the different shape and sensor might require different positioning.

[ssond]

I've tried tighter, looser ... higher up my arm, closer to my wrist ... rotating to the inside of my wrist, moving to other arm ... nothing seems to affect it.  I am relying on it to autodetect exercise, so maybe if I manually started excercise it would behave differently; I've read that it samples at a higher rate when in exercise mode.  What I do know is the charge 3 was accurate either way.

[DavideFitbit]

@ssond Thank you for your reply and for confirming that you already tried the steps suggested. 

The restart should to refresh the performance and adjusting the position of the device on the wrist is usually helpful as well to improve the accuracy, but in case that you experience this behavior again and you already tried all the steps suggested earlier, I would recommend that you get in touch with the Customer Support team for further assistance with this. The best way to get help for this problem is to chat with us online or give us a call. Click here to get connected. 

See you around.