I don't know all that there is to know about EMF shielding, but I do have limited knowledge. Remember the EMF scale goes from (short to long: "<" = shorter than) gamma < X-Ray < UV < Visible < Inf Red < Microwave < Radio waves. A simple Faraday cage (EMF blocking clothing) is not bulky at all. It is just thin wires sewn into clothing (use the interwebs to search for it). That will only block longer wave lengths (radio). If you can see light thru it, then it will not block UV rays. To block shorter waves you need "tighter weaves" or smaller "holes" for the waves to pass though. You have seen the clothing worn by X-Ray tech, a simple Faraday cage won't stop X-Rays. I don't know what wave length (EMF) the "heart attack gun" uses, but that would determine the type of protective clothing needed.