Characterising core body temperature response of free-moving C57BL/6 mice to 1.95 GHz whole-body radiofrequency-electromagnetic fields

Abstract

Overview

This study examines the core body temperature (CBT) response in free-moving adult male and female C57BL/6 mice. The mice were exposed to 1.95 GHz radiofrequency electromagnetic fields (RF-EMF) within custom-built reverberation chambers. Temperature measurements were collected using implanted temperature capsules, with continuous data logging and radiotelemetry post-exposure.

Findings

• RF-EMF exposures were conducted at various whole-body average specific absorption rates (WBA-SAR): 1.25, 2.5, 3.75, and 5 W/kg.
• There was a peak core body temperature increase within the first 16 minutes of RF-EMF exposure: +0.15°C, +0.31°C, +0.24°C, and +0.37°C at the respective exposure levels, with statistical significance observed at 2.5 W/kg.
• Only the 5 W/kg exposure showed a statistically significant increase in CBT immediately before exposure ended when compared to control (sham) conditions.
• The increased thermal load for exposures up to 5 W/kg was effectively compensated by the mice's thermoregulation systems.
• After the exposure, the elevated CBT at the 5 W/kg level was significantly reduced when compared to sham-exposed mice, suggesting post-exposure CBT measurements may not accurately reflect the impact of RF-EMF.
• An extended habituation period before RF-EMF exposure is essential due to the significant effects of handling on CBT in mice.

Conclusion

Exposure to 1.95 GHz RF-EMF at higher power densities can result in significant transient core body temperature increases in mice, indicating a clear link between electromagnetic field exposure and physiological change. Although thermoregulation can manage these changes within certain limits, these findings underline the importance of considering health risk connections when evaluating EMF exposures.