A Short Explanation of
"Pulse Electromagnetic Field Therapy"
To understand what this term means, let's first break it down into the component words. In this way, once we understand each component, we can re-assemble them to gain an understanding of the entire phrase.
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Pulse:
Everything vibrates and "pulse" refers to the frequency of the vibration, or how many times per set period of time a thing moves back and forth. When you feel your own pulse you can count the number of pulses, or "beats", per minute and know it should be within the range of 60 to 100.
The current in your home's electrical wiring pulses at 60 times per second and is measured in hertz (Hz) which is pulses per second. The pulse of your home stereo speakers will range between 20 Hz and 20,000 Hz depending on the note being played.
Hertz is used when measuring any pulse in seconds, all the way up to the fastest vibration we observe called Gamma Rays which vibrate at 100,000,000,000,000,000,000 times per second!
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Electromagnetic:
There are two types of magnets. What are called "permanent magnets" which are metals that naturally hold a magnetic charge, and "electromagnets" which are materials that become magnetic when an electric charge is applied to them.
Electromagnets are much more common because we can create the magnetism on demand and with the appropriate amount of power for the job we want them to do.
Sometimes, the two types of magnets are combined to perform a particular function. An example of this is your home stereo speaker. For a speaker to make sound, it must move in and out at a certain frequency for each note, thus making the air do the same in waves that your ears and brain will interpret as music. This is done by attaching the speaker cone to a coil of wire that, when a signal is sent to it, becomes an electromagnet. Surrounding this coil, or electromagnet, is a permanent magnet that is magnetic all the time.
We all know that when two magnets have like poles facing each other (North to North, or South to South), they will be repelled from each other, and opposite poles (North to South) will attract each other. In a speaker the permanent magnet has it's pole always facing the same direction because, well, it's permanent...it doesn't change. The coil, on the other hand, can be magnetized in either direction depending on which direction the current is sent down the wire. So, by rapidly changing the direction of the electrical current (there's that back and forth frequency thing again), you can cause the coil's north to face the permanent magnet's north (so they repel) then the coil's south faces the permanent magnet's north (so they attract) making the cone move in and out as many times per second as is needed for each note. Pretty nifty, these electromagnets!
There is one more distinction between a permanent magnet and an electromagnet beyond our ability to reverse the poles. Although everything has a vibration, or frequency, the permanent magnet gets its vibration from the materials it is made of so the magnetic charge itself does not have a frequency per se. It is always there at a steady rate. The same would be true for an electromagnet if it were created using direct current (which moves in only one direction) instead of alternating current (which alternates moving in one direction then the other a particular number of times per second, 60 times in our home's wiring, as mention above). When an electromagnet uses alternating current the magnetic charge itself has a frequency which is equal to the frequency of the current being applied to it. If you apply a 400 Hz electrical signal to the electromagnet, the magnetic charge also then has a frequency of 400 Hz.
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Field:
In this usage, "field" refers to the magnetic field. All magnets, whether permanent magnets or electromagnets, have a field or range in which their affects can be felt. The further you are from any magnet, the less magnetic attraction force remains. The reduction of this magnetic force is not linear with the distance from the magnet.
In other words, if you have X magnetic force (measured in Tesla or gauss) at one foot, it is not 1/2 X at two feet, 1/3 X at three feet and so on. Instead, it's more like X at one foot, 1/10th X at two feet, 1/100th X at three feet, etc. This is a very simplified explanation since the actual formulas are dependent on many variables and the shape of the magnetic field itself.
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Therapy:
The easiest of the four words in our phrase. Therapy is the application of treatment to relieve or heal a disorder. The term "therapy" can also be used when one applies protocols when in good health, or well being, to maintain or improve such.
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Hence, "Pulse Electromagnetic Field Therapy"
Now we can define Pulse Electromagnet Field Therapy, commonly referred to as PEMF. It is the application of an electromagnetic field that makes use of alternating current to create a pulsing (vibrating) field at particular frequencies to relieve or heal a disorder, and/or aid the body that is in general good health to improve in some way.