Gauss strength is measure of
magnetism named after the German mathematician Karl
Friedrich Gauss ( 1777–1855 ), who applied
mathematical principles to magnetism.
The gauss rating of a magnet
determines the speed in which it works, and the
thickness determines the depth of penetration. Some
magnet companies list their products by internal
gauss, not the external gauss rating. A quick rule
of thumb in determining proper gauss strength is
take the external gauss rating and multiply this
number by 3.9. So, a 600 gauss external strength
rated magnet can also be called a 2,340 gauss
internal strength rated magnet. It is important that
you are not misled into believing you're getting a
higher strength product, as both are correct ratings
for the same magnet.
Gauss strength can be misleading,
as the strength of the magnetic field falls off very
quickly as the distance from the surface of the
magnet increases. Depending upon the strength, size,
and distance from the skin, actual gauss strength
inside the human tissue can be much less than the
gauss rating of the magnet. If the magnet is to
penetrate deep into the body, it will need to be
stronger. To act one inch deep, it should be a 700
to 1000 gauss external strength rated magnet. For
two inches deep a 1200 to 2000 gauss external
strength rated magnet is best.
It is important to note that the
material of a magnet alone does not determine its
strength. It is a combination of material (strength)
and mass (size). To illustrate, lets take one
neodymium magnet (12,000 gauss) and one ceramic
magnet (4,000 gauss). If both magnets are the same
size, the neodymium will have the stronger field,
because it has a larger gauss rating.
Now let's assume that the same
neodymium magnet has a 1/2" diameter and 1/8"
thickness, and the ceramic magnet a 3/4" diameter
and 1/4" thickness. Even though the neodymium magnet
is rated 12,000 gauss and the ceramic is 4,000
gauss, the ceramic magnet will have the stronger
field. Why? Because, its greater mass helps to
produce a stronger field.
In most clinical studies the best
results are achieved with a magnetic field of 500 to
600 gauss within the tissue, which often requires a
much stronger magnet to deliver that amount of
energy within the body itself. The depth of
penetration of the magnetic field appears to be at
least as important as its strength. This is
extremely important. The larger the mass of the
magnet, the stronger and more effective it will be.
If the magnets are too small, the magnetic field
will drop below therapeutic levels before it even
reaches the injury site. Magnets made from Neodymium
(a rare earth metal), commonly called
Rare Earth Magnets, are unusually strong in
relation to their size, and therefore believed to
have the deepest penetrating fields. Some people may
have a skin reaction to direct exposure to some Rare
Earth Magnets. For this reason, many therapeutic
magnets are plated with gold or other non-reactive
metal, or contained within a wrap or magnetic
mattress pad.
Note:
If you come across a product that simply states
gauss strength without stating that it is the
surface or external rating, divide the value of the
product by 3.9. For example a 10,500 manufacturers
rating for a neodymium magnet, will measure
approximately 2,690 surface gauss using a digital
gauss meter (which is a very accurate instrument).
Something else to be aware of is
that gauss strength is not cumulative. In other
words if each magnet has a manufacturers gauss
rating of 3,000 and there are 10 magnets in the
product, the strength is still 3,000 gauss, NOT
30,000 gauss. Although, more magnets in a products
means that the magnets are spaced closer together,
creating a more uniform magnetic field. The number
of magnets needed to create a consistent field is
also dependent upon the size of the magnets. As
stated previously, larger magnets will create larger
fields. The key is that you do not want large spaces
between the magnets, as large spaces will create
empty gaps in the magnetic field, in which there is
no therapeutic benefit.