Muscle heating in human subjects with 915 MHz. Microwave contact applicator.
DeLateur BJ, Lehmann JF, Stonebridge JB, Warren CG, Guy AW · 1970
This 1970 study directly measured how 915 MHz microwaves heat human muscle tissue, providing early evidence of biological effects from microwave radiation.
Plain English Summary
This 1970 study examined how 915 MHz microwave radiation heats muscle tissue in human subjects using direct contact applicators. Researchers measured temperature changes in muscle tissue to understand how microwave energy penetrates and affects the human body. This early research helped establish fundamental data about how microwave frequencies interact with human tissue.
Why This Matters
This pioneering research from 1970 represents some of the earliest systematic investigation into how microwave radiation affects human tissue. The study's focus on 915 MHz is particularly relevant today because this frequency sits near the range used by many modern devices, including some industrial microwave applications and certain wireless systems. What makes this research significant is that it directly measured heating effects in living human subjects, not just laboratory models or animal studies.
The reality is that heating effects represent just one mechanism by which electromagnetic fields can affect biological systems. While this study focused on thermal effects that were clearly measurable in 1970, decades of subsequent research have revealed that EMF exposure can trigger biological responses at power levels far below those needed to cause detectable heating. Understanding these thermal thresholds remains important, but it's equally crucial to recognize that non-thermal effects may occur at the much lower exposure levels we encounter from everyday devices.
Figures from the Original Paper
Diagrams extracted from the original research document.
Exposure Information
Specific exposure levels were not quantified in this study. Duration: 20 minutes
Study Details
To evaluate the effectiveness of a 915 MHz microwave contact applicator for muscle heating in human volunteers, determining the depth of heating and temperature distribution in muscle and subcutaneous fat tissues.
Selected human volunteers were divided into two groups based on thickness of fat of the anterior thi...
In thin subjects (<1 cm fat), temperatures in all but the deepest muscle rose to a peak value and th...
Use of superficial cooling with application of microwave diathermy at 915 MHz allows adequate muscle heating without exceeding tolerance levels in the subcutaneous fat. The principal effect of cooling is upon the skin and fat, with little or no effect upon the muscle. An increase in blood flow in the superficial muscle layers provides uniform muscle heating over a period of time, by cooling the superficial layers as the deeper layers of muscle continue to heat with continued application. This mode of application compensates quite well for the subcutaneous fat layer.
Show BibTeX
@article{muscle_heating_in_human_subjects_with_915_mhz_microwave_contact_applicator__g6681,
author = {DeLateur BJ and Lehmann JF and Stonebridge JB and Warren CG and Guy AW},
title = {Muscle heating in human subjects with 915 MHz. Microwave contact applicator.},
year = {1970},
}