only exists in the minds of
those who have not read these scientific reports. This report, taken off the internet, is just one of doz-
ens of reports done on bio-electrical impedance analysis. If one but takes the time to look on the inter-
net they will find many such reports that give this same information.

This report along with all of the bio-electrical impedance analysis reports shows that frequencies do in
fact pass through the skin into the tissue of the body, using electrodes, as long as the proper methods
are used. There are limits to frequency penetration depending on whether a low frequency (5,000
hertz) is used or a high frequency (1,000,000 hertz or 1MHz) is used. These limits only apply to cell
penetration. These reports show that low frequencies only go through the connective tissue where
high frequencies can penetrate the cells of the body.

Because most of these types of reports are very technical we will give a simple explanation at the end
of each section, in blue print, if one is needed. The following report was once on the internet.

Bio-Electrical Impedance Analysis Report

Bio-electrical impedancemetry or Bio-electrical lmpedance Analysis (B.I.A.) initiated in France by A.L.
THOMASSET in 1962 today forms part of the arsenal of the means of exploration of biological tissues.
Already widely diffused in the USA and the Anglo-Saxon countries, this method has a promising fu-
ture. After a brief historical recapitulation, this work will present the basis on which the method was
founded, followed by some examples illustrating its numerous applications in the medical field, as well
as the perspectives opened up in biological research in general. In a word, bio-electrical
IM-
PEDANCEMETRY
is a simple technique allowing easy measurement of body water and its extra and
intra-cellular distribution in the organism.

Water is the main component of the human body where it represents 58 to 62%, of the body weight. In
many pathological cases this quantity varies. However, until now, because of the absence of simple
means, it was not measured. Today, this measurement is at the disposal of all physicians thanks to
BioElectrical Impedance Analysis: B.I.A.
2
The first concerned are nephrologists for the monitoring of hemodialysis, and nutritionists. But many
other physicians are concerned by this work, as for example those in medical and surgical intensive
care, those in units for the severely burned, cardiologists and those involved in metabolic disorders.
Moving away from such specialties, other physicians and researchers in sports medicine, occupational
medicine, thermal medicine, and of course in physiology and biology will find in this work many argu-
ments allowing them to develop their activities.

Historical Background

It was by studying the electrical activity of the brain by EEG that A.L. Thomasset in Lyon from 1955 to
1960 observed that the differences of potential could be similar to the law of Ohm and comply to the
formula:
U = R. I
. This idea led the author to look for the value of
R
, the electrical resistance of the
brain tissue, then step by step to measure that of the whole body. For this, the body being both an
ionic and non-homogeneous conductor, it was necessary to use an alternating current and not a direct
current. Because of this, the resistance studied took the name of impedance, a value expressed by
the symbol
Z
. The equality
U = R. I
is therefore written
U = Z. I
i.e.
Z = U/I, U
being the difference of
potential,
I
the intensity of the measurement current. Then, if we use for the measurement a current of
constant intensity
I
the potential in volts that is collected between two electrodes is equivalent to
Z

multiplied by this constant
U = Z.

Cte
and is representative of the impedance of the conductor. None-
theless, this measurement should be performed in certain precise conditions that we shall examine
later.

Now as from the beginning of the study most of these conditions were fulfilled, as the measurements
were systematically recorded in the morning, between 8 and 9am, in a medical department where
men and women were hospitalized for various reasons, it allows us to confirm that the measurements
were reproducible.

This reproducibility was the fundamental and determining quality without which the study could no
longer be pursued. All the authors who had studied the problem before, since d' Arsonval, Cole and
Curtis, Barnett, to mention only a few, placed without success the un-moistened electrodes on the skin
a capricious barrier for the current that needs only to be traversed by using moistened electrodes or
needle-electrodes inserted under the skin to avoid this pitfall.

Given this, the meaning of the body impedance measurements was a simple game thanks to the work
of the school of F.D. Moore at Harward, while H.P. Schwann in Philadelphia, Ch. Eyraud and J. Lenoir
[15] of the C.N.R.S. in Lyon validated the study scientifically.

3
In defense of physicians, it should be admitted that, until now, they had no simple means at their dis-
posal to perform such a measurement. Today, this means is now available to them through electrical
impedance measured by a method that we developed as from 1962 and experimented in various
fields of physiology and medical practice.

We trust that the readers will find in this presentation the basic elements of the method as well as
some examples of applications liable to throw light on their own observations.

Explanation: Alternating current (AC) is used for biological tissue. Earlier experimenters were unable
to read body impedance because they did not moisten the skin or insert needles. Today many body
impedance devices, which do not use needles, are used to determine if there are any blockages in the
electrical flow in the body. Many of these instruments, such as the Bio-Meridian an FDA approved de-
vice, use a metal probe to access meridians of the body. The skin must be moistened at each merid-
ian point in order to check the impedance.

Defibrillators used to electrically shock the heart use a con-
ductive jell in order to prevent burning of the skin, allowing the electrical current to enter the body.
Moisture is the key to getting frequencies into the body.


Electrical impedance

The word impedance comes from the Latin impedire meaning
to prevent, to stop from going on
. In
terms of electricity, impedance signifies the resistance of a conductor when an electric current passes.

However, conventionally speaking, the term
resistance
refers to the obstacle to the
direct current
,
and it is represented by the letter
R
.

The terms
impedance
refers to the obstacle to the
alternating current
and it is represented by the
letter
Z
.

Impedance
Z
, as resistance
R
, is expressed in
ohms
.

Explanation: Resistance refers to the obstacle of direct current. Impedance refers to the obstacle of
alternating current.

Electrical conductivity

The electric conductivity of a conductor is its capacity to conduct the current. It is called
conductance

for a direct current and
admittance
for an alternating current.
4
Conductance is equal to the inverse 1/R of the resistance.

Admittance is equal to the inverse 1/Z of the impedance.

In both cases, conductivity is expressed in
mho
(the inverse of the word ohm). In practice, use has
prevailed, and most often the designations resistance or impedance expressed in ohms are employed
to define conductivity.

Resistivity of a conductor

This is the resistance that a sample of this conductor with a length and section equal to one unit op-
poses to an electric current passing through it between two electrodes each with a section equal to
one unit and placed on two opposite faces of the volume thus defined of the sample to be measured.

Figure 3.1:
Determination of the resistivity












Example: The resistivity of copper is the resistance of a cube of this metal measuring 1 cm on each
side, through which passes a current between two electrodes measuring 1
cm2
placed on sides A and
B of this cube.

Resistivity is conventionally expressed by the Greek letter
p
. It is measured by means of a direct cur-
rent if we are dealing with an electric conductor such as iron or copper, and by means of an alternat-
ing current if it is an ionic conductor and furthermore non-homogeneous such as a biological tissue,
but in this case resistivity varies with the frequency of the measurement current, and one should indi-
cate the frequency of the current used in the following manner :
p
5kHz or
p
1MHz

Explanation: Resistance depends on both material used (body tissue) and frequency used.

1 cm
1 cm
1 cm 5
Notion of frequency of an electric current

A direct current has a null frequency. It passes through a conductor always in the same direction from
the positive pole to the negative pole.

An alternating current is an oscillating current usually sinusoidal which passes through a conductor
alternately in one direction then in the opposite direction, a certain number of times per second.

This number of times depends on the generator that produces it. It may vary from a few units (as is
the case for domestic current of 50 Hz (hertz), or cycles per second, in France), to several million cy-
cles per second. This number is called current f