Note: This study found no significant biological effects under its experimental conditions. We include all studies for scientific completeness.
ON THE POSSIBILITY OF NONTHERMAL BIOLOGICAL EFFECTS OF PULSED ELECTROMAGNETIC RADIATION
No Effects Found
LAWRENCE D. SHER, EDWARD KRESCH, HERMAN P. SCHWAN · 1970
1970 study found pulsed EMF fields no more biologically active than continuous waves at equal power levels.
Plain English Summary
Summary written for general audiences
This 1970 study examined whether pulsed electromagnetic fields could cause biological effects through non-thermal mechanisms, specifically field-induced forces rather than heat generation. Researchers found that pulsed fields have no greater ability than continuous wave fields to produce these force effects, and that heating always occurs before any potential field-induced biological changes.
Cite This Study
LAWRENCE D. SHER, EDWARD KRESCH, HERMAN P. SCHWAN (1970). ON THE POSSIBILITY OF NONTHERMAL BIOLOGICAL EFFECTS OF PULSED ELECTROMAGNETIC RADIATION.
Show BibTeX
@article{on_the_possibility_of_nonthermal_biological_effects_of_pulsed_electromagnetic_ra_g4441,
author = {LAWRENCE D. SHER and EDWARD KRESCH and HERMAN P. SCHWAN},
title = {ON THE POSSIBILITY OF NONTHERMAL BIOLOGICAL EFFECTS OF PULSED ELECTROMAGNETIC RADIATION},
year = {1970},
}Quick Questions About This Study
Pearl-chain formation refers to cells lining up in chains under electrical field exposure, used as a model to study field-induced force effects. This study showed the effect's time constant varies inversely with field strength squared.
No, this research demonstrated that pulsed fields have no greater ability to produce field-induced force effects compared to continuous wave fields of equal RMS (root mean square) field strength.
The study concluded that ANSI radiation protection guidelines would prevent genetic effects in humans via field-induced force mechanisms, if such effects exist, because thermal heating would always occur first.
In biological tissue with physiologic electrical conductivity, the study showed that heat development through electrical resistance losses occurs before field-induced forces can manifest, making thermal effects the primary concern.
The study identified heat development through electrical resistance losses and field-induced force effects caused by differences in passive electrical properties as the two primary interaction mechanisms between electromagnetic fields and tissue.