For centuries acupuncture, the subcutaneous insertion of metallic needles in certain parts of (mostly) the human body, has been practiced in various parts of the world for diagnostic as well as remedial purposes.

There have been plenty of reports of surprising effects of acupuncture on many types of diseases or discomfort, but it should be stressed that these reports are normally anecdotal in character, often collections of single cases, and rarely based on strict scientific investigations, including double blind test etc.

As far as explanations of why and how acupuncture works (if it does) we are also at a loss.

There are volumes written about acupuncture practices relative to various ailments, and almost all of these treatises talks about meridians and acupuncture points, but I still haven't seen any (scientific) attempt to explain why the insertion of a needle in one of these points should have any kind of effect.

I, personally, have no belief, one way or another, whether or not medians and acupuncture points are scientific facts. But let's just assume they are, and that they represent especially sensitive zones of the body.

Can we then think of a way a needle in such a point might increase the possibility of interacting with the surrounding atmosphere ?

John Wetling, who has worked with ion therapy and acupuncture for years, recently put this question to me. He also suggested that it might have something to do with ions and electric fields.

Being a skeptic and a doubter in all non-proven scientific matters, I redefined the question to the following:

Is there any way a metallic needle inserted subcutaneously in the skin can interact physically with the environment ?

And I think there is. And in order to explain that we have to look a little at the fascinating topic of atmospheric electricity.

In the outdoor atmosphere there will always be an electric field.

Under fair-weather conditions the field will be directed towards ground, and at flat horizontal areas the field will be homogeneous and have a value about 150 V · m^-1,

Fig. 1. Homogeneous atmospheric field at ground level Field strength ~ 150 V · m-1

The origin of the atmospheric electric field is thunderstorms. At any given time about 2000 thunderstorms are active, creating a voltage difference of about 300.000 volt, between the lower part of the ionosphere and the ground. The field will make airborne, charged particles move, the positive particles in the direction of the field, the negative in the opposite direction. The most important of the charged particles are the atmospheric ions (see for instance Niels Jonassen: IONS, Compliance Engineering, June/July 1999). The field-induced motion of the positive ions constitutes a current to ground with an average value of about 3 pA · m-2 (3 · 10-12 ampere per square meter).

Fig 2. Inhomogeneous atmospheric field around mountain ridge or house roof. field strength ~ 1000 - 2000 V · m-1	If now the surface considered is not horizontal the situation changes dramatically. In Fig. 2 is shown the field around a sharp structure, like a mountain ridge or maybe just a house roof. The field will no longer be homogeneous, but is said to be distorted, having values in the order of 1000-2000 V · m-1, i.e. about 10 times the values at a horizontal surface. Consequently the current to ground will be about 10 times as dense.
Fig. 3 Field between lightning rod and thundercloud Maximum field strength 3-4 MV · m-1	A special case of a strongly distorted field is shown in Fig. 3. We here have a house supplied with a (grounded) lightning rod. Above the house is a thundercloud with a negative base. We notice that the direction of the field lines is the opposite of that in fair-weather conditions, as shown in Figs. 1 and 2. The field strength has its highest value at the tip of the rod, and if the field strength here exceeds a critical value, the break-down field strength, of 3-4 MV? m-1 (3-4 million volt per meter) an electric discharge takes place. The discharge may take the form of a silent corona discharge or it may start a violent and dramatic lightning discharge. The field strengths and currents will be much larger than with fair-weather conditions, but the point is, that in both cases a distortion of the electric field, caused by a sharp or pointed "electrode" will increase the current from the atmosphere to the electrode.
Fig, 4 Field around acupuncture needle	And here we are finally approaching the topic of acupuncture. In Fig. 4 is shown a finger with an acupuncture needle inserted. The finger and the rest of the body is assumed to be grounded and placed in a positive field, i.e. a field directed towards any grounded objects. In the absence of the needle the current to the finger, caused by the field will be distributed more or less evenly over the finger.

The needle, however, will distort the field and concentrate the current to the needle and hence to the point where the needle is inserted.

Now the question obviously arises: What are the probability for the body to be in an electric field ?.

First of all it should be stressed, that the outdoor atmospheric electric field, discussed in Figs. 1, 2, and 3, is shielded almost one hundred percent by most building materials.

On the other hand (weak) electric fields are almost always present, even in indoor environments, originating from people moving or insulating materials being acciden-tally charged.

And at the same time there are always ions present in the atmosphere, originating primarily from decay of naturally occurring airborne nuclides.

As a consequence weak currents will constantly be flowing to the body, the direction depending on the origin of the fields in the environment.

As explained above the insertion of needles in the skin may increase the currents to selected parts of the body, and it is obvious that it is possible to increase the magnitude of the fields as well as of the ion concentrations and thus of the resulting currents by using well-established principles of physics.

This is for instance done with the so-called 3A-therapy developed by John Wetling.

The present little dissertation has demonstrated that basic principles of Physics predict that the subcutaneous insertion of needles in the skin may increase the transport of charged particles to the point of insertion.

And that is all.

To repeat:

The author takes no stand to the question of medians and acupuncture point or more generally to the possible effects of acupuncture.

But I believe that the practitioners of acupuncture and related practices may gain a little more insight in the physical background of their work by applying the principles presented above.