Good questions. I did a cursory search, I found some sites I trust that mentioned concerns of arrhythmias caused by Radio Frequency Energy, but not a lot of info at this time.
There were a plethora of advocacy sites about the health implications of RF Energy exposure, but I don't trust such pages. They may be well meaning, but may use data that has not fully been validated. I often use internet searches followed by the letters NIH (For the National Institutes of Health). Even at the NIH, published studies can often be found that contradict themselves, but the site is convenient for the more technical studies on health issues.
That said, a few things about radio frequency energy:
""Electromagnetic radiation has the following interesting properties
It can be found in nature or be man-made.
It does not require a medium for propagation.
It travels with the speed of light.
It carries energy as it propagates. The higher the frequency, the higher the energy associated with the wave.
It can transfer its energy to the matter on which it impinges.
Its transferred energy may be sufficient to break chemical bonds, ionizing the matter on which it impinges.
Its propagation obeys the inverse square law (see below).
It can be broadcast outwards to reach many locations or it can be formed into beams to reach a particular spot.
It travels in straight lines.
It can pass through walls.
In free space, all electromagnetic waves (radio, light, X-rays, etc.) obey the inverse-square law which states that the power density of an electromagnetic wave is proportional to the inverse of the square of the distance from a point source or:
Doubling the distance from a transmitter means that the power density of the radiated wave at that new location is reduced to one-quarter of its previous value.
The power density per surface unit is proportional to the product of the electric and magnetic field strengths. Thus, doubling the propagation path distance from the transmitter reduces each of their received field strengths over a free-space path by one-half.""
The radios, when receiving, obviously don't present much RF Energy. The Energy is transmitted by the antenna, unless your model differs, so the speaker/microphone won't represent much exposure. You won't be using both radios simultaneously, so the amount of RF Energy is limited to one radio, the same as if you were only wearing one. If they are worn at waist level, I'd be concerned about the exposure in those areas, such as the hips, but again, the exposure is largely limited to the amount of time you transmit, not the amount of time you wear the radios.
The vehicle radio uses coaxial cable to transmit the RF Signal to the antenna on the vehicle, so exposure to the RF Energy by the Radio itself is very limited, and the exposure to the RF Energy from the Antenna is more than partially shielded by the metal in the car.
Phones, they transmit short pings to the most available Cellular Antenna, this occurs all day long. The weaker the signal as received by the Cell Phone from the Cell Tower, the stronger will be the RF Energy from the Cell Phone attempting to communicate with it. Unlike Radios, Cell Phones handshake with the tower when receiving Text Messages and other notifications, thereby increasing the amount of time they actually are transmitting in addition to their use as a phone.
These are my opinions, I'm an Amateur Radio Operator, and I may not have everything right, but to the best of my knowledge it is.
I'd like to see links or search words for the material you have read, the topic interests me.
Thank you for you response to the query I posted and the interesting information you provided. In response to your request, here are some of the links I referenced;
MA/COM Manual for P7200 Portable radios:
http://www.manualslib.com/manual/484385/Tyco-Electronics-M-A-Com-P7200-Series.html?page=11#manual
Some quick links that I found, again, still dissecting them to check legitimacies and the studies and also continuing to research other sources:
http://beyondradiation.blogs.com/mblog/2012/05/heart-problems-and-pulsed-radiofrequency-rf-radiation.html
http://www.defenderpad.com/electromagnetic-radiation-studies/
http://www.ecolibria.com.au/Resources/electromagnetic-radiation-emr-and-potential-adverse-health-affects
http://www.whale.to/b/cherry6.html#Cardiac_Electrical_Sensitivity:__
http://www.suomensyh.fi/tiedostot/magda_havas_de_gruyter.pdf
Thanks for the links. I used to work for MA/Com Telecommunications (in digital communications). Been a long time since I've seen that name (I doubt they exist anymore, they were taken over by Hughes Networking.
Thanks much for the links, I'll take time to go through them.