Microwave ovens work at a frequency of 2.45 GHz. Their principle of operation is that molecules of fat, or water, absorb this radiation, because they are polar molecules with an electric dipole moment and rotate in response to the stimulus of the electromagnetic field of the microwaves. This absorbed energy is then dispersed throughout the material through vibrations and collisions between molecules and atoms.
Apparently, bluetooth works at around frequencies of 2.4 GHz. You are made up mostly of fat and water! It is therefore a fact that you are also an effective absorber of microwaves including bluetooth signals.
As for the health effects, a typical microwave oven produces around 800 Watts of power in order to heat small quantities of food. A bluetooth device for a mobile phone or similar will have a typical power of at most a few milli-Watts. I don't think there is too much danger of you cooking yourself. If there were any danger from this then you'd best be getting rid of your mobile phone entirely, since mobile phone signals are orders of magnitude stronger.