Wave height doesn't really enter into electromagnetic waves. It matters for mechanical things like ocean waves.
I think you might be looking for 'wave length', which is the distance between corresponding portions of a repeating wave. Back to the ocean wave: wave height would be the height from peak to trough, wave length would be the distance between peaks (or troughs). For em waves the corresponding values would be amplitude (related to electrical or magnetic field strength) and length (related to frequency).
The is a relationship between wavelength and photon energy for em waves; higher frequency means shorter wavelength and higher energy per photon. Once energy is high enough, then a single photon can cause chemical ionization. This is the realm of x-ray and gamma ray ionizing radiation.
Microwaves (including bluetooth) are much too low energy to be ionizing radiation. The photon energy is also so low that it is much better to approximate microwave radiation as being continuous for most purposes. But microwave radiation can still do damage.
The classic and known issue is thermal heating. Enough microwave radiation can damage tissue by heating it up.
Currently there is significant debate about the risk of non-thermal injury caused by microwave radiation. I think that there is lots we don't know on this topic. We can set a bound on the risk, because we are exposed to lots of microwave radiation and people haven't suddenly started dropping dead rapidly, but it is plausible to me that there are subtle risks.
A couple of years back there was a preliminary report from the National Toxicology Program study of cell phone radiation. (See
https://ntp.niehs.nih.gov/results/areas/cellphones/index.html for a general link, not the prelim report). As I recall they saw some very interesting results, including statistically significant increase in certain heart lesions, but also an increase in over-all life span, when exposed to rather high levels of cell phone type radiation. The levels were high but not 'thermal', and they saw differences in health effects with different types of modulation.
The last result is quite telling to me: my guess is that the radiation itself is not causing the injury directly, but is somehow being 'demodulated' and triggering the body to do things that can cause injury.
Bluetooth: much lower power levels than cell phones, in the same general frequency range, using different modulation. I think you could honestly say that the risk is very very low, but can't honestly say the risk is zero.
-Jon