Assessment of the Possible Health Effects of Ground Wave Emergency Network (1993) / Chapter Skim
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Human Laboratory and Clinical Evidence of Effects of Electromagnetic Fields
Human Laboratory and Clinical Evidence of Effects of Electromagnetic Fields
Pages 109-120
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From page 109... ...
At extremely low frequencies, one perceives the presence of electric fields through stimulation of vibration or pressure sensors. Studies of electric-field perception at 50-60 Hz have yielded thresholds of 2-30 kV/m, depending on the subject, posture, and humidity.6 7' 30 The threshold for cutaneous perception of ELF magnetic fields is unknown, but Graham et al.6 report that seated subjects were unable to detect the presence of 6~07.
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From page 110... ...
CIRCAI) IAN RHYTHMS Wever35~37 used a specially constructed living environment with no time cues to demonstrate that human circadian periods are lengthened by an average of 20 men when the living space is shielded against natural electric and magnetic fields.
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From page 111... ...
Long-term effects of small RF exposure on cardiovascular function remain largely unstudied. REACTION TIME The effects of ELF electric fields on human reaction time in response to auditory or visual stimuli have been extensively studied, but the results have been inconsistent.~4 27 Increased auditory or visual reaction times have been noted at thresholds ranging from I-2 V/m in a 3-Hz fields to 10 kV/m in a 50-Hz field.45 Decreased visual reaction times were found by Hauf46 in 50-Hz fields of 1 and 15 kV/m, but were not verified by later experiments in the same laborato~y.4i 47
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From page 112... ...
, Graham et al. found no consistent effect of field exposures on reaction times.~4 ~2
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From page 113... ...
BLOOD COMPOSITION Human laboratory studies examining field effects on blood composition are limited to the ELF range. Sander and colleagues48 exposed volunteers to 50-Hz electric fields of 10-20 kV/m for 6-22 h/d for a week and found no effects of exposure on the concentrations of 33 constituents of blood.
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From page 114... ...
However, the many laboratory studies of human exposure to ELF fields have not identified any deleterious acute effects, although data on chronic exposure are lacking. Studies demonstrating bone growth induced by kilohertz fields are interesting, but there is no evidence of effects of such exposures on healthy tissues.
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From page 115... ...
1974. Behavioral changes in human subjects associated with ELF electric fields.
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1985. Fracture healing in the rabbit fibula when subjected to various capacitively coupled electrical fields.
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1989. Proliferative and synthetic response of bovine growth plate chondrocytes to various capacitively coupled electrical fields.
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1979. Influence on vision of extremely low frequency electromagnetic fields, Acta Ophthalmol.
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1989. Acute effects of ELF electromagnetic fields: a field study of linesmen working with 400-kV power lines.
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1991. Dosimetry in electromagnetic field stimulation.
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