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).
Two power densities were tested at each of three ambient temperatures (24, 28, and 31°C).
Modulation type: CW
Exposure duration: continuous for 45 min
|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.|
|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.|
|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|
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.