Effect of non-thermal radiofrequency on body temperature in mice

Abstract

Communication technologies based on radiofrequency (RF) propagation bring great benefits to our daily life. However, their rapid expansion raises concerns about possible impacts on public health. At intensity levels below the threshold to produce thermal effects, RF exposure has also recently been reported to elicit biological effects, resembling reactions to cold. The objective of the present study was to investigate the effects of non-thermal RF on body temperature in mice and the related mechanisms. 3-months-old C57BL/6 J mice were exposed to a continuous RF signal at 900 MHz, 20 ± 5 V.m −1 for 7 consecutive days, twice per day during the light phase, for one hour each time. The SAR was 0.16 ± 0.10 W.kg −1. We showed that body temperature patterns in mice change synchronously with the RF exposure periods. Average body temperature in the light phase in the exposed group was higher than in the control group. The expression of the TRPM8 gene was not affected by RF in trigeminal ganglia. Furthermore, the injection of a TRPM8 antagonist did not induce a temperature decrease in exposed mice, as this was the case for sham-controls. These findings indicate that 900 MHz RF exposure at non-thermal level produce a physiological effect on body temperature in mice. However, the involvement of TRPM8 receptors in the mechanism by which RF induced changes in body temperature of mice which remains to be further explored. It must then be assessed if this effect is extrapolable to man, and if this could lead to consequences on health. Radiofrequency (RF) is known to carry insufficient quantum energy to eject electrons from atoms, in contrast to energy of CT scans or X-rays in medical applications. However, RF energy can penetrate the body and induce an elevation of temperature in body tissues as used with the microwave oven technology that is referred to as thermal effects of RF. To protect humans from harmful effects induced by excessive tissue heating, safety limits of RF exposure were established and were described in regulatory guidelines, such as those from ICNIRP (International Commission on Non-Ionizing Radiation Protection) and IEEE (Institute of Electrical and Electronics Engineers) 1. Up to now, except for the microwave auditory effect 2 , the effects of RF at non-thermal levels remain unexplained, poorly reproducible and controversial. In recent years, studies revealed responses induced in rodents by chronic or repeated RF exposure at low intensity which were similar to those observed in cold conditions. Pelletier et al. demonstrated that rats repeatedly exposed (5 weeks, 23 hours per day) to RF at 900 MHz with an intensity of 1 V.m −1 at warm ambient temperature, had a subcutaneous tail temperature 1.2 °C lower than controls, due to maintained vasoconstriction 3. This cannot be explained by a classical dielectric absorption. Also, exposed rats ate more than controls and spent more time to sleep at an ambient temperature of 31 °C, whereas controls spent more time at 28 °C 4. These results led the authors to suggest th...

The Effect of GSM Electromagnetic Field Exposure on the Waking Electroencephalogram: Methodological Influences

“…This is consistent with suggestions that a thermal mechanism may be responsible for the effect of RF-EMF exposure on the sleep EEG [Danker-Hopfe et al, 2016]. Similarly, a thermal change was recently demonstrated in mice in response to daily exposure to 0.16 W/kg whole body average SAR, which was not present during the first exposure (and thus due to an indirect physiological change rather than dielectric absorption) [Mai et al, 2020]. It follows that low-level RF-EMF is sufficient to engage physiologically meaningful thermoregulatory changes, and provides indirect support for the view that the RF-EMF effect on the EEG may represent an 'indirect' response to exposure [Perentos et al, 2013].…”

“…The possibility that the effect is mediated by direct activation of brain thermoreceptors (TRPM8) was tested in the above [Mai et al, 2020] study, where no support for this proposal was found. Although equivalent research has not been conducted in humans, and although there remains the possibility that different TRP receptors are involved, there is currently no evidence that direct activation of thermoreceptors by RF-EMFs is responsible for the above thermoregulatory changes.…”

Low‐Level Radiofrequency Exposure Induces Vasoconstriction in Rats

“…Instead, it may correspond to non-shivering thermogenesis, which is a heat production mechanism in adipose tissues that contributes to mammals' thermoregulation during cold exposure. With the same exposure pattern to 900 MHz RF with an SAR of 0.16 W.kg -1 , we could confirm that after 4 days, body temperature in mice was shown to increase synchronously with RF exposure sessions, which also did not occur on the first days [Mai et al, 2020]. In these studies, the rodents' responses to RF were similar to those described for thermoregulation in cold conditions.…”

Research for self-reported health problems after excessive talking time on mobile phones among university students

“…These non-thermal effects are also considered the most important from a medical point of view and are not covered by the established safety limits, because they are not directly measurable with a scientific instrument. This biophysical mechanism is defined as non-thermal if the interaction of the electromagnetic field with living material leads to specific effects that do not occur through the heating process (Glaser, 2005;Mai et al, 2020;Szasz et al, 2016). Non-thermal effects can be defined as biological effects resulting from a change in body temperature that is either less than 1°C or less than measurable or in the region of thermal noise (Scientific Committee on Emerging and Newly Identified Health Risks, 2015).…”