Study type: Medical/biological study (experimental study)

Effects of chronic exposure to radiofrequency electromagnetic fields on energy balance in developing rats. med./bio.

Published in: Environ Sci Pollut Res Int 2013; 20 (5): 2735-2746

Aim of study (acc. to author)

To study the effects of a chronic radiofrequency electromagnetic field on the main functions of body energy homeostasis (food intake, sleep and thermoregulatory processes). Another aim was to analyze the impact of the vasodilatator Prazosin on the tail temperature.

Background/further details

Two experiments were performed. First, 13 juvenile male rats were exposed to a radiofrequency electromagnetic field for 5 weeks at 24°C and 31°C (remark EMF-Portal editor: duration of exposure at 31°C room temperature not clear) room temperature and compared to 11 unexposed rats. Sleep pattern and EEG power spectrum were analyzed as well as food intake. Additionally, the subcutaneous tail temperature and the cortical temperature were recorded for 10 exposed rats and for 9 control rats.
For the second experiment, Prazosin (inhibits the peripheral vasomotor tone) was injected into 5 exposed and 5 unexposed rats and the tail temperature was recorded.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: CW
Exposure duration: continuous for 23.5 h/day, 7 days/week for 5 weeks

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Charakteristic
Exposure duration continuous for 23.5 h/day, 7 days/week for 5 weeks
Modulation
Modulation type CW
Exposure setup
Exposure source
Setup rats housed in individual 32 cm x 35 cm x 20.5 cm plastic cages with metallic grids at the bottom; cages placed inside a 2.4 m x 2.43 m x 1.6 m air-conditioned, sound-proofed climatic chamber; four 23 cm x 14 cm x 5 cm broadband, directional, vertically polarized gain antennas positioned horizontally 80 cm above the rats' cages; distance between the antennas = 48 cm
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 1 V/m - - - -
SAR 0.3 mW/kg - calculated whole body for 3 weeks old rats
SAR 0.1 mW/kg - calculated whole body for 8 weeks old rats

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

The frequency of REM sleep episodes was greater in the radiofrequency field exposed group than in the unexposed group, independently of the room temperature. At 31°C room temperature the exposed group showed a lower frequency of waking state and non-REM sleep episodes, compared with the control group, whereas at 24°C in exposed animals only the duration of waking states was lower than in control animals. Additionally, exposure to a radiofrequency field did not have a significant effect on the spectral power density of the EEG signal.
At 31°C room temperature, exposed animals had a significantly lower subcutaneous tail temperature than controls. No significant differences in the temperature of the tail were observed between exposed and unexposed animals at 24°C. Exposure did not appear to have a significant effect on the temperature of the cerebral cortex. After an injection of Prazosin, the temperature of the tail increased in exposed rats, while the temperature of the tail did not change in the control group.
In general, food intake was less at 31°C room temperature than at 24°C. At 31°C, exposed rats consumed more food than unexposed rats. There was no such a difference between exposed and unexposed rats at 24°C.
The authors conclude that electromagnetic field exposure did not modify strongly the overall sleep pattern and increased the peripheral vasoconstriction which promoted heat storage and the food intake.

Study character:

Study funded by

Related articles