Human exposure at two radio frequencies (450 and 2450 MHz): Similarities and differences in physiological response

Adair, E. R.; Cobb, Brenda L.; Mylacraine, Kevin S.; Kelleher, Sharon A.

doi:10.1002/(sici)1521-186x(1999)20:4+<12::aid-bem4>3.0.co;2-n

Cited by 49 publications

(34 citation statements)

References 23 publications

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“…Both mechanisms are plausible; however, up to date, no relevant literature reports are accessible. Human experimental studies performed thus far have revealed subtle thermophysiological changes during exposure to radiofrequency EMF [15,16]. However, those results cannot be compared with our findings due to different exposure conditions (whole body vs. head), different operating frequency of EMF exposure system (450 and 2450 MHz vs. 900 MHz) and site of measurement of the core temperature (esophageal vs. tympanic).…”

Section: Resultsmentioning

confidence: 99%

Changes in tympanic temperature during the exposure to electromagnetic fields emitted by mobile phone

Bortkiewicz¹,

Gadzicka²,

Szymczak³

et al. 2012

International Journal of Occupational Medicine and Environmental Health

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Objective: Mobile phones generate microwave radiation which is absorbed by exposed tissue and converted into heat. It may cause detrimental health effects. The aim of the experiment was to check if exposure to EMF emitted by mobile phone influenced the tympanic temperature. Material and Methods: Human volunteer study was performed on ten healthy young men, aged 22.1±4.7 years, examined three times: 1. on a day with 2×60 min of no exposure (sham day), 2. on a day with continuous, 60 min exposure and 60 min of no exposure, 3. on a day with intermittent exposure (4×15 min "on" and 4×15 min "off"). Exposure was generated by mobile phone (frequency 900 MHz, SAR 1.23 W/kg). The study was double-blind, performed under controlled conditions (at 24°C and 70% humidity). The tympanic temperature (T ty ) was monitored every 10 sec by a thermistor probe placed close to the aural canal membrane in the ear opposite the one in contact with mobile phone (contralateral position). Multivariate repeated-measures analysis of variance was used to calculate the results. Results: The mean T ty in the whole group during continuous exposure was significantly higher than during sham exposure (p = 0.0001). During intermittent exposure the temperature was lower than during sham day (difference was up to 0.11°C). Within an hour after continuous exposure, T ty was higher by 0.03°C and after intermittent exposure T ty was lower by 0.18°C in comparison with sham day. Two hours after exposure T ty was significantly lower (p = 0.0001) than after sham exposure (0.06°C and 0.26°C respectively). The trends in T ty during experiment differed significantly in relation to exposure conditions (p < 0.05). Conclusions: The results of this analysis indicate that the physiological response to EMF exposure from mobile phone was mostly related to type of exposure (continuous or intermittent).

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Section: Resultsmentioning

confidence: 99%

Changes in tympanic temperature during the exposure to electromagnetic fields emitted by mobile phone

Bortkiewicz¹,

Gadzicka²,

Szymczak³

et al. 2012

International Journal of Occupational Medicine and Environmental Health

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“…While many recent experimental studies have dealt with the macroscopic effects of high-frequency exposures, both whole-body [Adair et al, 1998;Adair et al, 1999] and single-organ [Vollrath et al, 1997;de Seze et al, 1998;Freude et al, 1998;Walters et al, 1998] calculations presented in this paper call for evaluation of effects at a microscopic, single-cell level. If exposures to high-frequency ®elds actually cause much higher power dissipation in cell membranes than in the cell interior and cell exterior, this could lead to structural changes in membrane proteins and the lipid matrix.…”

Section: Discussionmentioning

confidence: 99%

Theoretical evaluation of the distributed power dissipation in biological cells exposed to electric fields

Kotnik

Miklav?i?

2000

Bioelectromagnetics

150

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The paper deals with the power dissipation caused by exposure of biological cells to electric fields of various frequencies. With DC and sub-MHz AC frequencies, power dissipation in the cell membrane is of the same order of magnitude as in the external medium. At MHz and GHz frequencies, dielectric relaxation leads to dielectric power dissipation gradually increasing with frequency, and total power dissipation within the membrane rises significantly. Since such local increase can lead to considerable biochemical and biophysical changes within the membrane, especially at higher frequencies, the bulk treatment does not provide a complete picture of effects of an exposure. In this paper, we theoretically analyze the distribution of power dissipation as a function of field frequency. We first discuss conductive power dissipation generated by DC exposures. Then, we focus on AC fields; starting with the established first-order model, which includes only conductive power dissipation and is valid at sub-MHz frequencies, we enhance it in two steps. We first introduce the capacitive properties of the cytoplasm and the external medium to obtain a second-order model, which still includes only conductive power dissipation. Then we enhance this model further by accounting for dielectric relaxation effects, thereby introducing dielectric power dissipation. The calculations show that due to the latter component, in the MHz range the power dissipation within the membrane significantly exceeds the value in the external medium, while in the lower GHz range this effect is even more pronounced. This implies that even in exposures that do not cause a significant temperature rise at the macroscopic, whole-system level, the locally increased power dissipation in cell membranes could lead to various effects at the microscopic, single-cell level.

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“…A second study [Adair et al, 1999b] compared the results described above with those collected on a second group of volunteers, exposed to 2450 MHz CW energy. The basic protocol was identical, as were the three T a and response measures, with the addition of local skin blood flow (SkBF) at three sites on the body.…”

Section: Laboratory Studies Of Human Volunteersmentioning

confidence: 99%

“…In general, the steady state thermoregulatory responses (T co and 4 T sk , M, conductance, and sweating rate) to PW and CW fields were found to be the same at a given frequency, T a , and whole body SAR. These studies laid the groundwork for the studies of human volunteers reported earlier [Adair et al, 1998[Adair et al, , 1999b[Adair et al, , 2001a[Adair et al, ,b, 2002.…”

Section: Pulsed (Pw) Versus Cw Field Effectsmentioning

confidence: 99%

Thermoregulatory responses to RF energy absorption

Adair¹,

Black²

2003

Bioelectromagnetics

Self Cite

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This white paper combines a tutorial on the fundamentals of thermoregulation with a review of the current literature concerned with physiological thermoregulatory responses of humans and laboratory animals in the presence of radio frequency (RF) and microwave fields. The ultimate goal of research involving whole body RF exposure of intact organisms is the prediction of effects of such exposure on human beings. Most of the published research on physiological thermoregulation has been conducted on laboratory animals, with a heavy emphasis on laboratory rodents. Because their physiological heat loss mechanisms are limited, these small animals are very poor models for human beings. Basic information about the thermoregulatory capabilities of animal models relative to human capability is essential for the appropriate evaluation and extrapolation of animal data to humans. In general, reliance on data collected on humans and nonhuman primates, however fragmentary, yields a more accurate understanding of how RF fields interact with humans. Such data are featured in this review, including data from both clinic and laboratory. Featured topics include thermal sensation, human RF overexposures, exposures attending magnetic resonance imaging (MRI), predictions based on simulation models, and laboratory studies of human volunteers. Supporting data from animal studies include the thermoregulatory profile, response thresholds, physiological responses of heat production and heat loss, intense or prolonged exposure, RF effects on early development, circadian variation, and additive drug-microwave interactions. The conclusion is inescapable that humans demonstrate far superior thermoregulatory ability over other tested organisms during RF exposure at, or even above current human exposure guidelines. Bioelectromagnetics Supplement 6:S17-S38, 2003.

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Human exposure at two radio frequencies (450 and 2450 MHz): Similarities and differences in physiological response

Cited by 49 publications

References 23 publications

Changes in tympanic temperature during the exposure to electromagnetic fields emitted by mobile phone

Changes in tympanic temperature during the exposure to electromagnetic fields emitted by mobile phone

Theoretical evaluation of the distributed power dissipation in biological cells exposed to electric fields

Thermoregulatory responses to RF energy absorption

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