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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 security systems and induction cooktops may impair memory through brain inflammation.

Plain English Summary

Summary written for general audiences

Researchers exposed mice to 7.5 kHz magnetic fields (the frequency used in electronic security systems and induction cooktops) for 5 weeks and found memory impairment at higher exposure levels. Mice exposed to 120 μT showed slower learning and poorer memory retention after 48 hours, along with increased brain inflammation markers.

Why This Matters

This study reveals concerning evidence that intermediate frequency magnetic fields can impair memory and learning through brain inflammation. The 7.5 kHz frequency tested here is exactly what you encounter from electronic article surveillance systems at store entrances and induction cooking hobs in your kitchen. The reality is that these 'intermediate' frequencies between power lines and cell phones have received far less safety research, yet our exposure is rapidly increasing. What makes this particularly significant is that the memory impairment occurred at 120 μT, a level you could easily encounter from close proximity to induction cooktops or when walking through store security systems. The inflammatory response in the brain's memory center suggests a biological mechanism that could have long-term consequences we're only beginning to understand.

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_ce3320,
  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

This study found that 7.5 kHz magnetic fields at 120 μT impaired memory formation and retention in mice. Store security systems use this same frequency, suggesting potential cognitive effects from repeated exposure during shopping trips.
Induction cooktops emit 7.5 kHz magnetic fields, the same frequency that caused slower learning curves in this mouse study. The research suggests close proximity cooking could potentially affect cognitive performance through brain inflammation.
Memory impairment occurred at 120 μT but not at 12 μT exposure levels. This suggests a threshold effect where stronger 7.5 kHz magnetic fields are more likely to disrupt memory formation and retention.
The study found increased tumor necrosis factor alpha mRNA in the hippocampus, indicating inflammatory responses. This brain inflammation appears to be the mechanism behind the observed learning and memory impairments from 7.5 kHz exposure.
After 5 weeks of 7.5 kHz exposure, mice showed clear memory impairment over 48 hours. While the study didn't test recovery, the brain inflammation suggests these intermediate frequencies can cause measurable cognitive effects.