So, how far does the human electric field extend outside the body? May be only picovolts or in that range... But can we measure that? Does the field exist past our skin? Can things like meditation modify that? Or how about stuff like OOBE's like what some folks call astral projection? What do those practices to to the body's electric field?
There are some capacitive sensors (Electric Potential Integrated Circuit or EPIC) that can work through clothing fabric (which is a resistor). Within a few millimeters they are good enough for a diagnostic EKG. It's also used for stress monitoring, and can be embedded in a mattress or seat back.
There are also magnetoencephalography, magnetocardiography, magnetogastrography, and magnetomyography systems in use, which use superconducting quantum interference devices (SQUID). Those are orders of magnitude sensitive enough (10^-18 T sensitivity vs 10^-6 T to 10^-9 T for some body processes or 10^-15 T for neural activity).