Heating of Living Tissues
H. P. Schwan, A. Anne, L. Sher · 1966
This foundational 1966 Navy study on microwave tissue heating established thermal-based safety standards that still govern today's EMF regulations.
Plain English Summary
This 1966 U.S. Navy technical report examined how microwave energy heats living tissues, using skin simulants to measure temperature rise and energy absorption patterns. The research provided foundational data on how biological tissues respond to microwave radiation exposure. This early military study helped establish the thermal effects that became the basis for modern EMF safety standards.
Why This Matters
This Navy report represents some of the earliest systematic research into how microwave radiation affects living tissue - work that laid the groundwork for today's EMF safety standards. The focus on heating effects reflects the prevailing scientific view in 1966 that thermal damage was the primary concern from microwave exposure. What's significant is that this military research established the foundation for our current safety guidelines, which still rely almost exclusively on preventing tissue heating.
The reality is that decades of subsequent research have revealed biological effects occurring well below these heating thresholds. Yet our regulatory standards remain largely based on this thermal-only approach from the 1960s. Modern devices like smartphones, WiFi routers, and smart meters all operate under safety limits derived from this early heating-focused research, despite mounting evidence of non-thermal biological effects at much lower exposure levels.
Exposure Information
Specific exposure levels were not quantified in this study. Duration: Not specified
Study Details
To determine threshold sensations of warmth in terms of the incident power density when human subjects are irradiated with 10 cm electromagnetic waves
Human subjects were irradiated with 10 cm electromagnetic waves. Subjects sat in a shielded room exp...
The forehead skin of four subjects was irradiated with microwaves to determine the threshold sensati...
Human subjects irradiated with 10 cm electromagnetic waves showed that subjective awareness of warmth is not a very good indication of personal hazard. The reaction time should depend upon the thickness of the irradiated skin. The currently accepted safety standard for microwave irradiation says that 75 mw/cm² can be safely tolerated for two minutes. The average reaction times measured in these experiments varied between 15 and 73 seconds. These reaction times represent the minimum times for which an aware subject under ideal environmental conditions could detect the slightest perceptible sensation of warmth.
Show BibTeX
@article{heating_of_living_tissues_g7332,
author = {H. P. Schwan and A. Anne and L. Sher},
title = {Heating of Living Tissues},
year = {1966},
}