two spaced lights alternating, what does it mean?

[BatteryDangers]

My two green lights continue to flash.  Is this normal?  Is this a health hazard?

[Rflynch]

That is normal. Your Fitbit uses the lights to measure your pulse. 

[BatteryDangers]

Thanks for taking the time to reply to my question.  I was wondering of the continuous flashing posed any kind of a health hazard.  Since I have a concern I will disable the heart rate function if I am not exercising.  Thanks again, and enjoy the holiday.

Steve L.

[Rflynch]

They are just green led lights. If led lights are a health issue then we all have a lot of problems.There are a ton of useful metric recording your pulse continuously can give you especially your rating heart rate which is a key indicator of overall health. 

Here is more info on the technology. 

https://www.fitbit.com/purepulse

[Rich_Laue]

The common Led goves of only visable light. This light is unable to burn the skin like the light from a light bulb or the Sun.

In short this is the only type of light that is safe around someone who can not go out in the sun light.