Study type: Medical/biological study (experimental study)

Human exposure at two radio frequencies (450 and 2450 MHz): similarities and differences in physiological response. med./bio.

Published in: Bioelectromagnetics 1999; 20 Suppl 4: 12-20

Aim of study (acc. to author)

To study thermoregulatory responses of heat production and heat loss in seven volunteers during exposure to 2450 MHz continuous wave radiofrequency fields.
The results of this study were compared to results of an earlier study at 450 MHz (publication 2256).

Background/further details

Two power densities were tested at each of three ambient temperatures (24, 28, and 31°C).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2,450 MHz
Modulation type: CW
Exposure duration: continuous for 45 min

Exposure 1

Main characteristics
Frequency 2,450 MHz
Type
Charakteristic
Exposure duration continuous for 45 min
Additional info A report on the comparable earlier 450 MHz study (using identical procedures) can be found in the reference article.
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 1 m
Chamber The electrically shielded anechoic chamber was 2.45 m x 2.45 m x 3.66 m. A small climate-conditioned cubicle of 1.47 m x 2.00 m x 2.06 m was created by a 5-cm thick Styrofoam partition.
Setup Subjects wearing a bathing suit sat in a light plastic chair with their back towards the 15-dB standard-gain horn antenna. The electric field vector was aligned with the long axis of the subject's body (E-polarization).
Sham exposure A sham exposure was conducted.
Additional info After 30 min of equilibration to the prevailing temperature (24, 28, or 31 °C), the subjects were exposed or sham exposed for 45 min.
Parameters
Measurand Value Type Method Mass Remarks
power density 27 mW/cm² maximum measured - -
SAR 5.94 W/kg maximum measured - at the surface
power density 35 mW/cm² maximum measured - -
SAR 7.7 W/kg maximum measured - at the surface

Reference articles

  • Adair ER et al. (1998): Thermophysiological responses of human volunteers during controlled whole-body radio frequency exposure at 450 MHz.

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

No alteration in metabolic heat production occurred under any irradiation conditions at either frequency (450 and 2450 MHz). The magnitude of increase in those skin temperatures under direct exposure was directly related to frequency, but local sweating rates on back and chest were related more to ambient temperature and SAR. Both efficient sweating and increased local skin blood flow contributed to the regulation of the deep body temperature to within 0.1°C of the baseline level.

Study character:

Study funded by

Related articles