Measuring Body Voltage (EMF)
Measuring Body Voltage from our TR-3 Sauna
by Erik Johnson BSEE MBA
Education
What is Body Voltage?
Body voltage is a measurement that many people concerned about EMF (electromagnetic fields) use to judge the electric field exposure that comes from using a product. It is measured by taking an AC volt meter, connecting the black (negative) test lead to earth ground and having a person in the presence of the product, hold the red (positive) test lead. The AC volt meter then measures the low frequency voltage that is induced on the person by the electric fields they are exposed to. The higher the voltage is, the higher the electric field exposure and therefore the more undesirable the product.
What follows is the results of some measurements taken in our office. We measured our Transcend 3 Person sauna, with our patented triple antifield heaters and superior EMF mitigation, and compare that with measurements taken on a typical 2-person infrared sauna without EMF mitigation. What you will see is more evidence that High Tech Health is the undisputed leader in low-EMF infrared saunas.
Note that ambient body voltage levels in our office (levels totally unrelated to our product) contributed a significant amount relative to the extremely low levels coming from our product, so we present those as well.
Measurements in the High Tech Health Transcend 3-Person Sauna
Sauna Unplugged (ambient level)
Body Voltage: 97.5 mV (0.0975 V)
The sauna is not plugged in and contributes nothing to this measurement. This measurement shows the body voltage induced only by other sources of electric fields in our office.
Sauna Plugged In / Heaters Off
Body Voltage: 61.7 mV (0.0617 V)
The heaters are not on yet, but this measurement shows how the High Tech Health sauna lowers the body voltage from the external sources of electric field.
Heaters On / Light On
Body Voltage: 109.8 mV (0.1098 V)
Inside this TR-3 sauna, the lights are on and the heaters are all on. As in all of these measurements, the test subject is sitting back against the backrest as close to the back heater as possible.
Measurements in a Typical Infrared Sauna
Sauna Unplugged (ambient level)
Body Voltage: 150.5 mV (0.1505 V)
The sauna is not plugged in and contributes nothing to this measurement. This measurement shows the body voltage induced only by other sources in our office.
Heaters Off
Body Voltage: 52,690 mV (52.69 V)
The heaters are not on yet, but a significant voltage is induced on the test subject. This is caused by high electric field exposure.
Heaters On / Light On
Body Voltage: 29,950 mV (29.95 V)
Inside this typical infrared sauna, the lights are on and the heaters are all on. A high body voltage is induced on the test subject but, surprisingly, it is less than when the sauna is not heating.
Summary of Results
The High Tech Health sauna induced a body voltage of 109.8mV (0.1098 V). That is only 12.2 mV higher than the ambient level present during the test, and only 48.1 mV higher than the level in the sauna before it was turned on.
The typical infrared sauna when turned on induced a body voltage 272 times higher on the test subject than the High Tech Health sauna.
Discussion
The High Tech Health TR-3 sauna has the most heaters of any of our models and so should be the highest exposure of any of our models. The test subject sat as close to the center back heater as possible, which should produce the highest body voltage, however the results show that the High Tech Health sauna produces almost no body voltage and is the lowest body voltage by far of any infrared sauna.
It is worth noting that high body voltage measurements, like those seen from the typical infrared sauna, are easy to reproduce and are affected very little by variations in position of the test subject or different test subjects. However, the extremely low body voltage levels seen from the High Tech Health sauna can be easily affected by small changes to the position of the test subject. In these tests, the test subject tried to remain still between measurements.
Also, it would have been nice if we could have found a position in our office with unmeasurably low ambient body voltage. Then we could have seen results dependent only on our sauna, but we were not able to find such a location. If we get a chance to retest in such an environment, we will update this page
When it comes to designing an infrared sauna to have negligible electric field, all places with electricity in the sauna must be considered, not just the heaters. I find body voltage to be an excellent single measurement that reflects all the places in a sauna that need electric field mitigation and is probably the best single number you can use when comparing electric field exposure between saunas.