I decided to start with this parameter because the intensity of pulsing magnetic fields, generated by PEMF devices, is one of the most crucial specifications in order to obtain successful results.
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". In the past magnetic field strength was also expressed in Gauss (symbol G) which number is 10.000 times larger than Tesla.
Since intensity is very relevant for pulsed electromagnetic field 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.
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.
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 your own alarm clock. Your clock contains a piezo crystal with an electrical connection at both sides. When your clock reaches the preset wake-up time, an oscillating electrical voltage is applied to the crystal causing small mechanical movements and 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 and if the intensities of the pulsing magnetic fields are too low to sufficiently penetrate deep inside the body, no effect will take place!
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 be possible to show its existence still 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.
You can clearly smell a rat when a company starts talking about the intensity of the earth magnetic field. Claiming that weak natural magnetic fields work better than stronger fields is not only pure scientific nonsense but also clearly misleading.
Here is the proof: 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. How will a device generating only 70 micro Tesla perform according the claims of these manufacturers??? Your guess is as good as mine!
Attempts are made to scare potential customers by misquoting the World Health Organization who indicates magnetic field strengths for continuous magnetic fields, e.g. radiated by power lines. People making this claim clearly have no clue about the differences between a continuous magnetic field and a pulsed electromagnetic field, which only have in common the words ‘magnetic field’!
A micro Tesla device has the same intensity as an air-conditioner, fridge, mixer etc. and possibly offer not more than a placebo effect.