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EMF Study
(Database last updated on Mar 27, 2024)

ID Number 635
Study Type In Vivo
Model 350, 700 MHz, 1.2, 2.45, 2.8, 5.6, 9.3 GHz (CW, PW - simulating military radar) exposure at thermal levels to rats and analysis of thermoregulation and physiological responses
Details

Series of studies of RF exposure to rats at thermal levels and analysis of thermoregulation and physiological responses (heart rate, bp, respiratory rate, and core temperature / thermoregulation). In one study, Sprague Dawley rats were exposed to RF and analyzed for heart rate, bp, respiratory rate, and core temperature / thermoregulation. In early studies, rats were exposed to 5.6 GHz (CW or PW- 2 usec pulses, 250 or 500 pulses/sec) RF under far-field conditions in an anechoic chamber (ambient temperature 24.0 +/- 0.5 C) at SARs of 6 or 12 W/kg to simulate military tracking radar exposure. Exposure was performed until core body temperature reached 39.5 degrees C, at which time exposure was stopped and re-continued when the temperature returned to 38 degrees C for 3 cycles. Changes in heart rate were observed and correlated with the rate of change and not the absolute change in core temperature. No changes in mean arterial blood pressure or respiratory rate were observed. The authors concluded such exposures would probably not have serious long-term physiological consequences. In subsequent studies (1988, Physiol Chem Phys Med NMR 20:135-143, rats were injected with Thorazine (chlorpromazine; CPZ) which significantly decreased the rate of core temperature increase, lowered arterial bp, and decreased survival time with exposure. Similar results were observed in other studies with 5.6 and 2.8 GHz exposures (Aviat Space Environ Med (1961) 55:1036-1040; Clin Exp Pharmacol Physiol (1985) 12:1-8; Int. J. Radiation Biol. (1989) 56:1033-1044) indicating that anesthetized rats receiving drugs may be more susceptible to thermal effects at high levels of RF exposure, although thermoregulatory efficiency during limited RF exposure (1 C cycles) is minimally affected. In other studies, Sprague-Dawley rats (female) were intermittently exposed to 2.06 GHz (CW or PW) at 50-200 mW/cm, or to 9.3 GHz (CW or PW-500 pulses per second, 2 usec pulse duration) whole-body average SARs of up to 18.6 W/kg at various chamber ambient temperatures for a time sufficient to increase rat colonic temperature 1 degree. Exposure was then discontinued, and after Tc recovery, the procedure was repeated for as many cycles as desired. Repeated exposure over periods of several months resulted in a loss of thermoregulatory efficiency as heat dissipation times gradually increased, although it returned to near-normal after a 40 day rest period. No major differences between the effects of CW and PW MW exposure were observed using either 2.06 or 9.3 GHz. During exposure at 9.3 GHz, skin and tympanic temperature increased significantly at a faster rate than colonic temperature. Although heart rate increased, blood pressure and respiratory rate did not change with 9.3 GHz exposure. Skin heating and heart rate change were greater using 9.3 GHz as compared to 2.06 GHz. In other studies, Sprague-Dawley rats were exposed to 2.8 GHz (CW or PW - 2 usec, 500 pps) at SARs of 8.4, 12.6, 16.8, or 21 W/kg in the far field in an anechoic chamber. Each animal exposed to produce seven cycles of 1 C colonic temperature swings (from 38.5 to 39.5 degrees C) over the course of 3-4 hr. Core and skin & tympanic temperature, heart rate, arterial blood pressure, and respiratory rate were monitored. The authors conclude that no significant difference was observed between CW & PW exposure in various physiological responses. In another study, Fisher 344 rats were exposed to 2.8 GHz at whole body SARs of 14.4 W/kg (colonic temperature increase of 1 degree C). Ketamine anesthesia increased the time necessary for the 1 degree colonic temperature increase, as well as stabilized heart rate and blood pressure, during MW exposure. Other studies looked at the effects of 700 MHz and 2.45 GHz exposures with similar results.

Findings Effects (only at thermal levels)
Status Completed With Publication
Principal Investigator Brooks AFB, USA
Funding Agency AF, USA
Country UNITED STATES
References
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  • Jauchem, JR et al. Aviat. Space Environ. Med., (1995) 66:992-997
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  • Frei, MR et al. Physiol. Chem. Phys. & Med. NMR, (1992) 24:1-10
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  • Frei, MR et al. Physiol. Chem. Phys. Med. NMR, (1989) 21:65-72
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  • Frei, M et al. J. Microwave Power & EM Energy, (1988) 23:81-84
  • Frei, M et al. J. Microwave Power & EM Energy, (1988) 23:85-93
  • Jauchem, JR et al. Physiol. Chem. Phys. Med. NMR, (1988) 20:135-143
  • Jauchem, JR et al. Aviat. Space Environ. Med., (1985) 56:1183-1188
  • Jauchem, JR Gen. Pharmacol., (1985) 16:307-310
  • Jauchem, JR et al. Clin. Exp. Pharmacol. Physiol., (1985) 12:1-8
  • Jauchem, JR et al. Proc. Soc. Exper. Biol. Med., (1984) 177:383-387
  • Jauchem, JR et al. Aviat. Space Environ. Med., (1984) 55:1036-1040
  • Jauchem, JR et al. Physiol. Chem. Phys., (1983) 15:429-434
  • Heinmets, F Physiol. Chem. Phys., (1982) 14:519-531
  • Heinmets, F et al. Report, (1982) :-
  • Jauchem, JR International archives of occupational and environmental health., (1997) 70:9-21
  • Jauchem, JR Autonomic & autacoid pharmacology., (2006) 26:121-140
  • Comments

    Frey and Eichert critizised the work performed at 5.6 GHz and suggested effects due to exposure to the heart would not be expected because the energy would not penetrate the skin and reach the heart (J Bioelectricity 5:201-210, 1986). Jauchem and Frei (J Bioelectricity (1987) 6:219-221) responded that the heart rate increased due to peripheral heating of blood and circulatory transport of heat to the heart.

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