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Kumari K, Koivisto H, Viluksela M, Paldanius KMA, Marttinen M, Hiltunen M, Naarala J, Tanila H, Juutilainen J

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Authors not listed · 2017

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7.5 kHz magnetic fields from induction cooktops and security systems may impair learning and memory through brain inflammation.

Plain English Summary

Summary written for general audiences

Researchers exposed mice to 7.5 kHz magnetic fields for 5 weeks and found that higher exposure levels (120 μT) impaired learning and memory abilities. The mice showed slower learning in maze tests and memory problems after 48 hours, along with increased brain inflammation markers. This suggests intermediate frequency magnetic fields from common devices like induction cooktops may affect cognitive function.

Why This Matters

This study provides concerning evidence that intermediate frequency magnetic fields - the type emitted by induction cooking hobs and electronic security systems - can impair cognitive function in mammals. The 7.5 kHz frequency tested here sits right in the range of everyday consumer devices, making these findings directly relevant to human exposure scenarios. What's particularly noteworthy is that the researchers observed clear learning and memory deficits at 120 μT, a field strength that's achievable near induction cooktops and other household appliances. The fact that these effects occurred alongside increased inflammatory markers in the brain suggests a biological mechanism that could translate to human health impacts. While industry often dismisses non-thermal EMF effects, this research adds to the growing body of evidence that electromagnetic fields can influence brain function through pathways beyond simple heating.

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 7.5 kHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 7.5 kHzPower lines50/60 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Specific exposure levels were not quantified in this study.

Cite This Study
Unknown (2017). Kumari K, Koivisto H, Viluksela M, Paldanius KMA, Marttinen M, Hiltunen M, Naarala J, Tanila H, Juutilainen J.
Show BibTeX
@article{kumari_k_koivisto_h_viluksela_m_paldanius_kma_marttinen_m_hiltunen_m_naarala_j_tanila_h_juutilainen_j_ce4088,
  author = {Unknown},
  title = {Kumari K, Koivisto H, Viluksela M, Paldanius KMA, Marttinen M, Hiltunen M, Naarala J, Tanila H, Juutilainen J},
  year = {2017},
  doi = {10.1371/journal.pone.0188880},
  
}
DOI: 10.1371/journal.pone.0188880PubMed: 29206232

Quick Questions About This Study

Yes, this study found that 5-week exposure to 7.5 kHz magnetic fields at 120 μT impaired memory retention over 48 hours in mice. This frequency and field strength are similar to what you'd encounter near induction cooking hobs and electronic security systems.
The 120 μT exposure level caused learning impairments, while 12 μT did not. For context, 120 μT is achievable near induction cooktops and some electronic article surveillance systems, making this finding relevant to everyday human exposure scenarios.
Yes, mice exposed to 7.5 kHz magnetic fields at 120 μT showed significantly increased tumor necrosis factor alpha mRNA in brain tissue. This inflammatory marker suggests the magnetic field exposure triggered an immune response in the brain.
The study used 5 weeks of continuous exposure to observe learning and memory deficits. This relatively short timeframe suggests that intermediate frequency magnetic fields can impact cognitive function faster than previously thought for this frequency range.
This research raises questions about safety, as electronic article surveillance systems emit similar 7.5 kHz frequencies. While the study used continuous exposure rather than brief encounters, the cognitive effects observed suggest potential concerns for workers with chronic exposure.