Study type: Medical/biological study (experimental study)

Thermoregulatory, metabolic, and cardiovascular response of rats to microwaves med./bio.

By: Phillips RD, Hunt EL, Castro RD, King NW
Published in: J Appl Physiol 1975; 38 (4): 630-635
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Aim of study (acc. to author)

To study the effects of 2450 MHz microwave irradiation on thermoregulation, metabolism, and cardiovascular function of rats.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.45 GHz
Modulation type: pulsed
Exposure duration: 30 min
  • SAR: 11.1 mW/g maximum (cf. remarks) (6.5 mW/g, 4.5 mW/g, and 0 mW/g)

Exposure 1

Main characteristics
Frequency 2.45 GHz
Exposure duration 30 min
Additional info Phillips R.D. Mechanisms of injury for radiation-induced decrease in cold tolerence. J. Appl. Physiol. 28: 821-825, 1970.
Modulation
Modulation type pulsed
Pulse width 2.5 ms
Repetition frequency 120 Hz
Exposure setup
Exposure source
Setup Rats were contained in holders of Bollman type which were constructed of polyform end plates that were joined by Lutice rods to form a cylindrical space for the animals, 18 cm long by 6.2 cm in diameter.
Additional info A base plate of Polyfoam was located between the two end plates to provide a footrest.
Parameters
Measurand Value Type Method Mass Remarks
SAR 11.1 mW/g maximum cf. remarks cf. remarks 6.5 mW/g, 4.5 mW/g, and 0 mW/g

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Animals that received 27.7 cal/min (4.5 mW/kg) for 30 min exhibited an initial transient increase in colonic and skin temperatures but no changes in other functions.
Animals irradiated at 40.1 cal/min (6.5 mW/kg) had greater increases in colonic and skin temperatures immediately after exposure, followed by overcompensation and lower than normal colonic temperatures for about 3 h. The metabolic rate was depressed in this group of rats for 3 h. Bradycardia developed within 20 min after irradiation and persisted for about 3 h.
Rats that received 68.2 cal/min (11.1 mW/kg) for 30 min had responses similar to those of the 40.1 cal/min group, but the alterations were more severe and lasted longer. Additionally, a number of transient abnormalities were observed in the ECG tracings of rats that had received the highest dose, including irregular rhythms and incomplete heart block.
The physiological changes found in this study can be attributed to the heating induced by irradiation.

Study character:

Study funded by