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Temperature dependence of the dielectric constant of blood at low frequencies

Bioeffects Seen

H. Schwan · 1948

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Early research showed human blood's electromagnetic properties change with temperature, establishing how EMF interacts with living tissue.

Plain English Summary

Summary written for general audiences

This 1948 research by Schwan examined how temperature affects the dielectric properties of human blood when exposed to low-frequency electromagnetic fields. The study investigated how blood's electrical characteristics change with temperature variations, providing foundational data for understanding how EMF interacts with biological tissues. This early work helped establish the scientific basis for measuring electromagnetic effects in living systems.

Why This Matters

This foundational 1948 study represents some of the earliest scientific investigation into how electromagnetic fields interact with human biological materials. Schwan's research on blood's dielectric properties laid crucial groundwork for our modern understanding of how EMF penetrates and affects living tissue. The temperature dependence findings are particularly relevant today because they help explain why EMF exposure effects can vary based on physiological conditions. What this means for you is that your body's response to electromagnetic fields from power lines, appliances, and other ELF sources isn't constant - it changes based on factors like body temperature and blood flow. This research helped establish the scientific foundation that later studies would build upon to demonstrate biological effects from everyday EMF exposures.

Finding

Es ergibt sich, daß, im Gegensatz zur Leitfähigkeit, die DK nicht temperaturabhängig ist und infolgedessen die im mittelfrequenten Gebiet beobachteten Dispersionserscheinungen auf der inhomogenen Struktur des Materials beruhen.

In their words

Es ergibt sich, daß, im Gegensatz zur Leitfähigkeit, die DK nicht temperaturabhängig ist und infolgedessen die im mittelfrequenten Gebiet beobachteten Dispersionserscheinungen auf der inhomogenen Struktur des Materials beruhen.

Figures from the Original Paper

Diagrams extracted from the original research document.

chartPage 2 - AI-described figure: Figure 1 illustrates the wavelength dependence of the dielectric constant (DK) of blood.
diagramPage 3 - AI-described figure: Figure 3 illustrates the arrangement of spheres at maximum achievable volume concentration.
diagramPage 5 - AI-described figure: Figure 5 illustrates the setup of a bridge circuit used for measuring blood dielectric constant.
diagramPage 6 - AI-described figure: Diagram showing the setup and measurement of electrical properties in blood cells (Figure 6)

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 10 MHz to 1 GHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 10 MHz to 1 GHzPower lines50/60 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Specific exposure levels were not quantified in this study.

Study Details

Die Temperaturabhingigkeit der Dielektrizitatskonstante von Blut bei Niederfrequenz zu untersuchen

Die DK von Blut wurde bei Niederfrequenz gemessen. Die Messungen wurden mit einer Briickenanordnung ...

Die DK des Blutes ist praktisch konstant. Sie schwankt von drei Werten abgeschen, um lediglich etwa ...

Die DK von Blut ist nicht temperaturabhingig. Im Gegensatz zur Leitfahigkeit ist die DK nicht temperaturabhingig und infolgedessen die im mittelfrequenten Gebiet beobachteten Dispersionserscheinungen auf der inhomogenen Struktur des Materials beruhen. Die hohe DK biologischer Substanzen erschwert die Bestimmung der DK von Blut nicht einfach.

Cite This Study
H. Schwan (1948). Temperature dependence of the dielectric constant of blood at low frequencies.
Show BibTeX
@article{temperature_dependence_of_the_dielectric_constant_of_blood_at_low_frequencies_g67,
  author = {H. Schwan},
  title = {Temperature dependence of the dielectric constant of blood at low frequencies},
  year = {1948},
  
  
}
No DOI on file for this study.

Quick Questions About This Study

Schwan investigated how temperature changes affect blood's dielectric constant when exposed to low-frequency electromagnetic fields. This research examined the electrical properties of human blood under different temperature conditions, providing foundational data for EMF-biological tissue interactions.
Temperature changes alter blood's electrical properties, affecting how electromagnetic fields penetrate and interact with tissue. Warmer blood has different dielectric characteristics than cooler blood, which influences EMF absorption and biological responses in the human body.
This foundational work established that biological materials like blood respond differently to electromagnetic fields under varying conditions. It helped scientists understand that EMF effects aren't constant but depend on physiological factors like body temperature and circulation.
Dielectric properties describe how blood responds to electromagnetic fields - essentially how it conducts or resists electrical energy. These properties determine how deeply EMF penetrates tissue and how much energy is absorbed by biological systems.
Low-frequency electromagnetic fields from power lines and electrical systems interact directly with blood circulation. Understanding these interactions helps explain how everyday EMF exposures might affect cardiovascular function and overall health through blood-based mechanisms.