Are the LED lights safe?

[tjohej]

I wonder if the LED lights that shine through your skin on the clock are completely harmless, or if there is any chance it could cause "issues" with the body?
I read the description on what they do: "Your current HR uses the optical HR sensor located on the inside of the device. This optical HR sensor uses two green LED lights to shine through your skin and illuminate blood-flow within your capillaries. In doing so, the sensor in the middle will read that blood-flow and determine your heart rate.""

Is having these light shining through your skin day and night 100% safe? Anyone that know more about this technology?

 

[Dave47]

AFAIK, light has been used to measure HR in clinical settings for decades. I don't recall it ever being a problem. I'd say the same for the B2 and other fitness devices.

 

[Nate Silver]

Its not unheard of for some people to experience some skin irritation underneath the hr sensor in these devices. I couldn't say whether it is caused from the LED lights, or just skin contact with the device itself though. I've never experienced it with the Band, but I also have a Garmin Fenix 3 HR which I also wear pretty much 24/7......well, 23/7 anyway, and from time to time I've noticed a red spot under where the sensor is located. So far it hasn't caused anything further. We probably won't definitively know whether its 100% safe for a number of years, since sometimes that's how long it takes for problems to surface. But I'd think the likelihood is pretty slim for any actual problems beyond something like Contact Dermatitis, which could happen with anything you wear for long periods where air can't circulate, and dirt could build up.