Heart rate inaccurate during exercise

[ColoradoGman]

I have read posts and did suggested adjustments by placing unit further down wrist and loosening it.  Cleaned contacts as well.  Still, when I exercise on the stationary bike my HR is 20 BPM lower on the Fitbit vs the HR monitor on the bike which is accurate.  Please advise what I can do to fix this.  I bought the unti primarily to monitor my exercise and this is a miss. Thanks. 

[SunsetRunner]

Optical HR monitoring is never perfect; but to improve results the device should rest securely 2 finger widths above the wrist bone (moving from wrist towards elbow).  It should fit snug enough during the exercise that the device does not slip easily when you are sweating and moving.  If the device ambient light from the environment can make the sensor read a weaker reflected light from the device.  Also if device is too close to the wrist tendons moving and bone will interfere with delivering a consistent reading.

Hope that helps!

(For reference: see pages 10-11 in the Charge 5 user manual https://help.fitbit.com/manuals/manual_charge_5_en_US.pdf)

[ColoradoGman]

Thanks. I did try moving it 2 finger lengths above the wrist bone but it
was still off by almost 20 bps. Does sweat effect the sensors? I do get a
pretty good sweat going (on wrists as well).

[SunsetRunner]

Speaking from personal experience with Fitbits and other companies' wearables, the optical sensor can be affected by: sweat, arm hair, tattoos, skin type etc.  For example I have black arm hair and caucasian skin, so I trim the arm hair back on my wrist for less interference. Sometimes with more intense exercises I will wear a sweat-band above the fitbit. Then, if need I just adjust my heart zone ranges to calibrate to (match) my heart exertion. 

Ref: See the heading "Custom Zones" https://help.fitbit.com/articles/en_US/Help_article/1565.htm?Highlight=adjust%20heart%20rate%20zones

[ColoradoGman]

Appreciate the advice. I’ll give that a try.

[SunsetRunner]

Please share whether it helps or not.  

Take care