heart rate sensor & tattoos?

[i_mitche]

I have a full sleeve on my left arm & my charge 5 will not pick up my heart rate -- is this due to the tattoos? 

[charleskn]

Skin tone and tattoos can adversely affect optical HR sensors, but I wouldn't expect there to be no HR at all. If you take your tracker off, and move it, do you see the optical sensor's LEDs flash? I know the Charge 4 has a setting to turn the HR on/off under the tracker's settings. Maybe check that. It seems (from the posts on Fitbit) that the HR setting sometimes "magically" turns off, sometimes.

REF: https://help.fitbit.com/manuals/manual_charge_5_en_US.pdf & 

https://help.fitbit.com/articles/en_US/Help_article/1582.htm

[Rich_Laue]

My thought would be yes it could, depending on the ink saturation and or color. If your tat is of the same color as the sensor led then possibly yes. Black ink absorbs all colors, passing little through the skin. 

A quick search seems to agree. 

You may also find sunscreen lotion affecting the ability to read the SpO2, for the same reason

[i_mitche]

I do see the LED flashing when I take it off, and if I move it to my right arm (where I also have tattoos but less dense in my wrist area) it picks it up some but not consistently. ☹️

[i_mitche]

Thanks Rich. After moving it around some I do think it must be due to the ink saturation on my wrist.. I tried my other wrist where my tattoos aren’t as dark & it will pick up some but not consistently ☹️ Bummer. Going to have my husband give it a wear around and see if it’s really the tattoos or if the sensor isn’t working properly.

[LZeeW]

@i_mitche   You're going to find out that it is the tattoos.  The heart rate sensor looks for pulsations in very tiny blood vessels in the upper layer of the skin, the same layer where tattoo ink is deposited.  The ink absorbs the light and can "hide" the blood vessels.

[i_mitche]

Thank you!! Definitely seems like that’s the case. Bummer. 

[charleskn]

You can switch the tracker to your other arm. There is a setting (in the app, I believe) for wearing the tracker on your dominant or non-dominant hand.

[i_mitche]

There is! & I did do that, but also have tattoos on that arm. Not as dense so it does get my HR but not as accurately 

[charleskn]

If you want good HR for exercise, I use a Polar Verity sense arm band that can be on my forearm, bicep (probably even my calf). It works great, assuming you have fewer tats on your other forearm/bicep.