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Physiological interaction processes and radio-frequency energy absorption.

Bioeffects Seen

Adair ER, Adams BW, Hartman SK · 1992

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Squirrel monkeys exposed to microwave fields showed metabolic heat production reductions proportional to the SAR, with skin temperature changes identified as the primary source of the neural signal for physiological changes during exposure in the cold.

Plain English Summary

Summary written for general audiences

Researchers exposed adult male squirrel monkeys to 450-MHz or 2,450-MHz continuous-wave fields in cool environments to study how the body responds to radio-frequency heating. During brief exposures in the cold, the reduction of metabolic heat production was directly proportional to the SAR, and 2,450-MHz energy was a more efficient stimulus than the resonant frequency. In the steady state, exposure at the resonant frequency produced a regulated increase in deep body temperature, described as not unlike that which occurs during exercise. Researchers concluded that skin temperature changes are the primary source of the neural signal for a change in physiological interaction processes during radio-frequency exposure in the cold.

Why This Matters

The study monitored colonic and several skin temperatures, metabolic heat production, and evaporative heat loss continuously throughout exposures. Whole-body SARs ranged from 0 to 6 W/kg at 450 MHz and from 0 to 9 W/kg at 2,450 MHz. The researchers set out to determine both the thresholds for response change and the steady-state thermoregulatory compensation for body heating during exposure at resonant and supra-resonant frequencies. Exposure to microwave fields at the resonant frequency may generate heat deep in the body, potentially resulting in hyperthermia.

Exposure Details

SAR
0 - 6 W/kg
Source/Device
450-MHz
Exposure Duration
10 min or 90 min

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextExtreme Concern - 0.1 W/kgFCC Limit - 1.6 W/kg
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 450 MHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 450 MHzPower lines50/60 HzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Study Details

Because exposure to microwave fields at the resonant frequency may generate heat deep in the body, hyperthermia may result. This problem has been examined in an animal model to determine both the thresholds for response change and the steady-state thermoregulatory compensation for body heating during exposure at resonant (450 MHz) and supra-resonant (2,450 MHz) frequencies

Adult male squirrel monkeys, held in the far field of an antenna within an anechoic chamber, were ex...

Colonic and several skin temperatures, metabolic heat production, and evaporative heat loss were mon...

Detailed analyses of the data indicate that temperature changes in the skin are the primary source of the neural signal for a change in physiological interaction processes during RF exposure in the cold.

Cite This Study
Adair ER, Adams BW, Hartman SK (1992). Physiological interaction processes and radio-frequency energy absorption. Bioelectromagnetics 13(6):497-512, 1992.
Show BibTeX
@article{er_1992_physiological_interaction_processes_and_790,
  author = {Adair ER and Adams BW and Hartman SK},
  title = {Physiological interaction processes and radio-frequency energy absorption.},
  year = {1992},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/1482414/},
}
PubMed: 1482414

Cited By (22 papers)

Quick Questions About This Study

The study used adult male squirrel monkeys held in the far field of an antenna within an anechoic chamber.
During brief radio-frequency exposures in the cold, the reduction of metabolic heat production was directly proportional to the SAR.
2,450-MHz energy was a more efficient stimulus than the resonant frequency.
A regulated increase in deep body temperature accompanied steady-state exposure at resonance, described as not unlike that which occurs during exercise.
Researchers found that temperature changes in the skin are the primary source of the neural signal for a change in physiological interaction processes during radio-frequency exposure in the cold.