Intensity

PEMF therapy can only be effective if the field strength of the pulsing electromagnetic signal is sufficiently powerful to penetrate deep enough inside the cells and bones to cause the desired effect. In order for this to happen the applied energy levels must be sufficiently high, otherwise only a minimal and superficial effect will occur.

 

Magnetic field intensity or magnetic field strength is defined in Tesla (symbol T) and named after the scientist Nikola Tesla. It is also known as "magnetic flux density" or "magnetic induction". Previously electromagnetic field intensity was expressed in Gauss (symbol G) which is 10,000 times larger than Tesla.

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Because intensity is very important for effective PEMF therapy devices, and because very often confusion exists between micro Tesla and milli Tesla (milli is a factor 1000 x larger than micro), hereunder is a table showing the differences between these values. Some manufacturers write mTesla in order to confuse the reader, but the correct scientific way for use of these symbols is mT for milli Tesla and μT for micro Tesla.

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In 1956 two Japanese scientists discovered the so called piezo-electric effect of bones. By mechanically bending a bone and measuring an electrical voltage between two electrodes attached over the bone, they proved that electrical properties exist inside bones. An example of the piezo electric effect is the alarm clock, which contains a piezo crystal with an electrical connection at both sides. When the clock reaches the preset wake-up time, an oscillating electrical voltage is applied to the crystal causing small mechanical movements, resulting in the sound you hear.

When a pulsing magnetic field penetrates into a bone the opposite effect takes place. The pulsing magnetic effects cause tiny mechanical movements, resulting in small electrical currents inside the bones and cells. These micro currents are responsible for the beneficial effects occurring inside the body, but if the intensities of the pulsing magnetic fields are too low to sufficiently penetrate deep inside the body, no effect will take place.

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The only way to prove if the field indeed completely penetrates the body is to check if it is still possible to detect a pulsing magnetic field at the opposite side of the body. E.g. if the field is applied at the back, it must also be detectable at the chest, otherwise it can never penetrate deep enough into the body.

The human body is unable to feel the magnetic pulses themselves but only the effects they cause. You can, however, easily detect a sufficiently strong pulsed magnetic field by holding a static magnet in your hand above the applicator containing the coils. You can now clearly feel the pulses in your hand with exactly the same pulse repetition rate (frequency) generated by the device. This effect happens because the pulsing magnetic fields distort the static magnetic field of the magnet, resulting in the pulsing movements you can now easily feel in your hand.

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Something is wrong if a company talks about the intensity of the earth magnetic field and tells you that weak natural magnetic fields work better than strong PEMF. Some even like the expression "Less is more" which is of course scientific nonsense. The geomagnetic field strength varies over the surface of the earth. The intensity of the magnetic field over South America has a minimum strength of 22 micro Tesla and reaches a maximum of 67 micro Tesla over the south of Australia. This explains why a PEMF device with a field strength of only 70 micro Tesla cannot penetrate deep into the human body and influence cells and cannot have much beneficial effects.