Do you have any information about the absolute heating caused? I dunno, but a 4W light bulb is still hot to the touch - not sure I'd want to poke my brain with a 1W heat source.
Here's a simple experiment: wrap you hand around your cellphone antennae and call someone. Do you feel ANY heat? Didn't think so.
There are several problems with your bulb analogy. 1) While human body is almost opaque to the infrared light (i.e. absorbs most of the heat from the bulb) it is almost transparent to radio waves (that's why you don't lose cell phone signal when in a crowd of people). 2) Only a small spot heats up from the bulb - spread the same heat over the whole hand and you'd barely feel it. Spread over the volume of your body and you won't feel anything.
Btw, photons from Bluetooth headset ~3 times more energetic than the ones from your cell phone (2.4GHz vs 850MHz)
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