Effect of Exposure to a Radiofrequency Electromagnetic Field on Body Temperature in Anesthetized and Non‐Anesthetized Rats

Abstract

Exposure to a radiofrequency (RF) signal at a specific absorption rate (SAR) of 4 W/kg can increase the body temperature by more than 1°C. In this study, we investigated the effect of anesthesia on the body temperature of rats after exposure to an RF electromagnetic field at 4 W/kg SAR. We also evaluated the influence of body mass on rats' body temperature. Rats weighing 225 and 339 g were divided into sham-and RF-exposure groups. Each of the resulting four groups was subdivided into anesthetized and non-anesthetized groups. The free-moving rats in the four RF-exposure groups were subjected to a 915 MHz RF identification signal at 4 W/kg whole-body SAR for 8 h. The rectal temperature was measured at 1-h intervals during RF exposure using a small-animal temperature probe. The body temperatures of non-anesthetized, mobile 225 and 339 g rats were not significantly affected by exposure to an RF signal. However, the body temperatures of anesthetized 225 and 339 g rats increased by 1.9°C and 3.3°C from baseline at 5 and 6 h of RF exposure, respectively. Three of the five 339 g anesthetized and exposed rats died after 6 h of RF exposure. Thus, anesthesia and body mass influenced RF exposure-induced changes in the body temperature of rats.

Biological Effects of Exposure to a Radiofrequency Electromagnetic Field on the Placental Barrier in Pregnant Rats

“…In our previous study, however, we reported no significant changes in body temperature during exposure to RF‐EMF at an SAR of 4 W/kg in adult male rats. The body mass of male rats used in our previous study was heavier than those of the pregnant rats used in this study [Kim et al, 2020]. In our previous study, however, we reported no significant changes in body temperature during exposure to RF‐EMF at an SAR of 4 W/kg in adult male rats.…”

The effect of exposure to RF-EMF from the laboratory simulator of 5G NR base station on physiological parameters and cognitive abilities of male wistar rats of different ages

“…In our experiments, the temperature in the rooms where the animals were kept was constant at 21 ± 2 °C. It was shown previously that thermoregulatory sensitivity RF-EMF in rodents depends on body weight, ambient temperature, and ability to move 23 . They were found to be important factors influencing the SAR threshold to increase large intestine temperature.…”

Measuring radiofrequency field‐induced temperature variations in brain MRI exams with motion compensated MR thermometry and field monitoring

“…For instance, a study of RF exposure performed on anesthetized and non-anesthetized rats has shown that when exposed at the same SAR level, non-anesthetized rats were able to maintain their body temperature while the anesthetized ones had an increased body temperature eventually leading to death. 36 A study performed on the human calf, a poorly perfused muscle, also reported a continuous temperature rise that reached several degrees. 35 Interestingly, a study using an MR spectroscopy-based thermometry approach showed cerebral temperature increases in humans of 0.4°C when drinking hot water.…”

“…The comparison between these animal and the current human studies is, however, not straightforward due to anatomical differences between species and the use of anesthetic agents on the animals that can affect thermoregulation. For instance, a study of RF exposure performed on anesthetized and non‐anesthetized rats has shown that when exposed at the same SAR level, non‐anesthetized rats were able to maintain their body temperature while the anesthetized ones had an increased body temperature eventually leading to death 36 . A study performed on the human calf, a poorly perfused muscle, also reported a continuous temperature rise that reached several degrees 35 .…”