Forschungsgemeinschaft Funk e.V.

Edition Wissenschaft

Back to overview

Edition No. 21/E December 2005

Are thermoreceptors responsible for „non-thermal“ effects of RF fields?

Prof. Dr. Roland Glaser, Humboldt University Berlin


The existence of “non-thermal“ effects of weak RF-fields has been discussed again and again. In these papers the expression “non-thermal“ is mostly not related to the biophysical mechanism, but used in a empirical sense.

Usually, an effect is considered “non-thermal“ if it is not accompanied by a predictable or measurable temperature increase, or if it does not correspond to effects occurring after conventional heating of a similar degree. This approach does not take into consideration the real system of thermoregulation, its ambivalence, and its high sensitivity. Recently, a specialized class of transport proteins have been found functioning as thermosensors in cell membranes not only in cells of specialized organs, but also in normal keratinocytes and other cells. The signal-to-noise ratio in this system of thermoreception is optimized by averaging the response of many proteins and cells and many steps of information processing with various time constants from below microseconds for the primary reactions of the membrane proteins, milliseconds for nerve excitations, and eventually, tenths of seconds or even minutes for behavioral consequences. The threshold of this system can be lower than the sensitivity of our technical devices for measuring or controlling temperature in experiments. Considering this, the effects found in experiments with weak RF-fields in fact could be “quasi-thermal“ or “subtle thermal“ reactions of the biological system of thermosensation and thermoregulation.

A number of reactions is conceivable, occurring at temperature elevations that are not high enough to be registered by the central nervous system. Protein expression, influences on local blood circulation, or other effects could be the the result of thermal stimulation, even if there is no measurable temperature increase and no behavioral consequences or conscious “warm“ sensations. If “non-thermal“ effects, at least those found in experiments using accurate exposure systems and exact dosimetry, really are based on the activation of the molecular system of thermosensors, they consequently must be classified as ‘everyday’ responses without real significance to health.

Back to overview