B Do contracting muscles emit electric fields?

[jaketodd]

I bought an EMF meter that can discriminate to electric fields, and it is highly sensitive to the proximity of my body. What is it in the human body that emits electric fields? Is it muscle activity? Maybe many things in the body? Thanks.

 

[.Scott]

People conduct radio energy. They pick it up from one place and retransmit it.
For example, if you are sitting close to a CRT (old TV or oscilloscope) you will be transmitting lots of EM.

 

[Baluncore]

Detecting muscle noise, EMG, is difficult.
https://en.wikipedia.org/wiki/Electromyography

 

[berkeman]

People conduct radio energy. They pick it up from one place and retransmit it.
For example, if you are sitting close to a CRT (old TV or oscilloscope) you will be transmitting lots of EM.

We don't do anything different compared to any other bag of saltwater our size...

I bought an EMF meter that can discriminate to electric fields, and it is highly sensitive to the proximity of my body.

Go out into the middle of an open field and try it again. Most likely you will not see anything. If in your test you are in your house near AC Mains wiring, the AC voltage (current) from your parasitic capacitance to that wiring is probably what your EM meter is sensing.

 

[sophiecentaur]

Detecting muscle noise, EMG, is difficult.

ECG instruments are commonplace and not too high tech. They used to consist of nothing more than sensitive galvanometers, in the past. The electrical activity of the heart is measured by placing electrodes (pads) at a number of places on the torso. They record signals in the order of a few mV but that is very different from a radiated field. Is EMG a different thing, apart from the muscles it looks at?

The OP is referring to an EMF meter which, afaiaa, is for assessing the potential harm from exposure to EM fields. What he's been measuring / detecting will almost certainly be the effect of the presence of his body on the fields that are there anyway. An FM radio can be affected greatly by the presence of a human - either improving or worsening the signal strength, depending, in the same way as wiggling the whip antenna about. The body acts like a piece of metal of similar size and re-radiates signals in the vicinity.

Without knowing about the frequencies involved, it's hard to comment usefully on what he's seeing but there's not much chance of it coming from his body if a simple hand held device can register it.

PS EM Hazard assessment is a bit of a black art and getting relevant and meaningful readings of fields is pretty hard. Not least, the antenna / probe needs to be well calibrated and characterised if the results could be accepted in a court of law when someone claims Industrial Injury!

 

[berkeman]

This thread has become a magnet for pseudoscience nonsense posts (which have been deleted). @jaketodd please do the "outstanding in your field" experiment that I suggested. Thank you. Thread is closed.