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Immune System

Effects of 21-kHz intermediate frequency magnetic fields on blood properties and immune systems of juvenile rats.

No Effects Found

Ushiyama A, Ohtani S, Suzuki Y, Wada K, Kunugita N, Ohkubo C. · 2014

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Two weeks of 21-kHz magnetic field exposure showed no immune system effects in young rats, suggesting short-term intermediate-frequency exposures may not immediately compromise immune function.

Plain English Summary

Summary written for general audiences

Researchers exposed young rats to 21-kHz magnetic fields (similar to frequencies used in induction heating and some wireless charging) for one hour daily over two weeks to test effects on blood and immune system function. The study found no significant changes in immune cell activity, blood cell counts, or other immune markers, with only a minor phosphorus level change that remained within normal ranges. This suggests that short-term exposure to these intermediate-frequency magnetic fields may not substantially impact immune function in developing animals.

Why This Matters

This study addresses an important gap in our understanding of intermediate-frequency magnetic fields, which fall between the well-studied extremely low frequency (ELF) and radiofrequency ranges. The 21-kHz frequency tested here is relevant to induction heating systems, some wireless power transfer technologies, and certain industrial applications that people may encounter. While the researchers found no immune system effects at 3.8 mT exposure levels, this represents relatively high-intensity, short-duration exposure compared to typical environmental levels. The study's focus on juvenile rats is particularly valuable since developing immune systems may be more sensitive to electromagnetic exposures. However, the 14-day exposure period represents just a snapshot of potential effects. What this research demonstrates is that acute exposure to intermediate-frequency fields doesn't produce immediate, measurable immune dysfunction, but longer-term studies examining chronic, lower-level exposures would strengthen our understanding of real-world health implications.

Exposure Details

Magnetic Field
3.8 mT
Source/Device
21-kHz
Exposure Duration
1 h/day for 14 consecutive days.

Exposure Context

This study used 3.8 mT for magnetic fields:

Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 3.8 mTExtreme Concern - 5 mGFCC Limit - 2,000 mGEffects observed in the Extreme Concern range (Building Biology)This level is 19 times the FCC limit
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 21 kHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 21 kHzPower lines50/60 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Study Details

The aim of this study is to investigate Effects of 21-kHz intermediate frequency magnetic fields on blood properties and immune systems of juvenile rats.

Male Sprague-Dawley rats (4-5 weeks old) were divided into three groups: Cage-control, sham, and 3.8...

Hematological parameters were not affected by IF-MF exposure. Other immune functions such as the cyt...

Our results suggest that exposure to 21-kHz sinusoidal IF-MF at 3.8 mT for 1 h/day for 14 days did not affect immune function in juvenile rats.

Cite This Study
Ushiyama A, Ohtani S, Suzuki Y, Wada K, Kunugita N, Ohkubo C. (2014). Effects of 21-kHz intermediate frequency magnetic fields on blood properties and immune systems of juvenile rats. Int J Radiat Biol. 90(12):1211-1217, 2014.
Show BibTeX
@article{a_2014_effects_of_21khz_intermediate_3459,
  author = {Ushiyama A and Ohtani S and Suzuki Y and Wada K and Kunugita N and Ohkubo C.},
  title = {Effects of 21-kHz intermediate frequency magnetic fields on blood properties and immune systems of juvenile rats.},
  year = {2014},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/24899391/},
}
PubMed: 24899391

Cited By (19 papers)

Quick Questions About This Study

A 2014 study found no significant immune system effects from 21-kHz magnetic fields similar to those in induction heating. Researchers exposed young rats daily for two weeks and found no changes in immune cell activity, blood cell counts, or immune function markers.
Research on 21-kHz magnetic fields (similar to wireless charging frequencies) found no effects on blood cells in juvenile rats. The study showed no changes in blood cell counts or other blood parameters after daily exposure for two weeks.
A controlled study found that 21-kHz intermediate frequency magnetic fields did not affect immune function in developing rats. Researchers measured immune cell activity, T cell populations, and other immune markers with no significant changes observed after exposure.
Current research suggests minimal immune risks from 21-kHz EMF exposure. A 2014 animal study found no significant effects on immune cell activity, blood parameters, or immune system function after daily exposure for two weeks.
Research on frequencies similar to induction cooktops (21-kHz) found no significant health impacts on immune or blood systems in animal studies. Only minor phosphorus level changes occurred, which remained within normal healthy ranges.