ELECTRICAL IMPEDANCE OF THE HUMAN BODY FOR HF (2-30 MHz) BAND (INITIAL RESULTS)
R. W. Carson, W. E. Innis · 1970
This 1970 study mapped how human bodies conduct 2-30 MHz radio signals, foundational research for understanding EMF bioeffects.
Plain English Summary
This 1970 technical report by Carson examined how the human body conducts electrical signals in the high-frequency (HF) radio band from 2-30 MHz. The research measured electrical impedance, which determines how electromagnetic energy interacts with human tissue. This foundational work helped establish how radio frequency energy penetrates and affects the human body.
Why This Matters
This research represents crucial foundational work in understanding how radio frequency energy interacts with human biology. The 2-30 MHz frequency range Carson studied includes amateur radio, shortwave broadcasting, and various industrial heating applications that people encounter today. What makes this significant is that electrical impedance determines how deeply RF energy penetrates tissue and where it deposits its energy in the body.
The reality is that this type of basic research from 1970 laid the groundwork for understanding EMF bioeffects, yet regulatory agencies still rely heavily on thermal-only safety models developed from similar early studies. Put simply, we've known for over 50 years that the human body responds electrically to RF energy, but safety standards haven't kept pace with the biological implications of this fundamental interaction.
Exposure Information
Specific exposure levels were not quantified in this study.
Study Details
To measure actual whole-body rf impedances of human beings in the 2 to 30 MHz range, verify the estimate of the theoretical study, establish tolerance limits for the human body impedance in the 2-30 MHz range, develop a general statistical model to describe the whole-body impedance, and detect variations between individuals as guidance for further investigation.
A randomized complete block design was initially chosen as the best approach to the experimental stu...
The results of the experiment are contained in Appendix C. The data set for each individual consists...
The data collected during the experimental program show that the real part of the impedance of the human body follows approximately a negative exponential for the frequency range of interest. The impedance for each of the individuals measured was in good agreement with the theoretical values established during the theoretical study of Reference 1. During the experimentation several covariates suggested themselves as possible explanations of the variation between individuals. These covariates may be the size of the hand, the cross section area of the arm, the length of the arm, and the weight of the individual. Further studies of the human body parameters in this frequency range are planned; construction of a precise mathematical model which incorporates the significant covariates will be attempted; replicate measurements will be collected to provide a measure of experimental error; and further instrumentation accuracy studies will be conducted in order to refine the mathematical model.
Show BibTeX
@article{electrical_impedance_of_the_human_body_for_hf_2_30_mhz_band_initial_results__g5547,
author = {R. W. Carson and W. E. Innis},
title = {ELECTRICAL IMPEDANCE OF THE HUMAN BODY FOR HF (2-30 MHz) BAND (INITIAL RESULTS)},
year = {1970},
}