Fitbit vs Garmin RHR

[baghe61]

I am coming down with something. Last night I had both sense 2 and 965 on.

Both detected worse hrv and other metrics to indicate I’m sick.

One major difference is RHR - Fitbit detected 69 and my Garmin said 59.

Seems to be a large difference. With how I’m feeling 69 seems more accurate. 59 seems much closer to my norm.

Although sleep data the Fitbit said I had a good sleep 75 sleep score. Garmin said 43.

I think Garmin got that more accurate.

[Triletics]

@baghe61 both watches use different algorithms and different input data to calculate RHR. You comparing apples to oranges. The accuracy is unknown without something that serves as the "ground truth" for the data. In this case, see whether trends match rather than absolute values (for example, HRV trends mostly match between my Fitbit and Garmin watch despite the absolute values being different).

[LZeeW]

Hello @baghe61 and welcome to the Community.  @Triletics is right, you're comparing apples to oranges.  Fitbit's proprietary algorithm uses your heart rate, day and night, during all periods at rest.  Garmin uses a 30 minute time period when your heart rate was at its slowest, usually during sleep.

As a physiologist, I can tell you, for certain, that Garmin is the outlier here.

[Triletics]

@LZeeW the problem with Fitbit is that the algorithm is unknown hence it cannot be validated so I wouldn't blindly assume its superiority. Also, sleep is also a rest state so I see nothing wrong with using it for the computation. Fitbit would need to be a little more open about how they do their magic 🤷 Understanding the algorithm is key to knowing what the value really means in a particular system.