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Effects of extremely low frequency magnetic field on oxidative balance in brain of rats

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Ciejka E, Kleniewska P, Skibska B, Goraca A · 2011

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Brain cells showed oxidative damage from 30-minute magnetic field exposures but adapted to longer 60-minute sessions, revealing complex dose-response effects.

Plain English Summary

Summary written for general audiences

Researchers exposed rats to 40 Hz magnetic fields at 7 mT (milliTesla) for either 30 or 60 minutes daily over 10 days to study brain cell damage. They found that shorter exposures (30 minutes) increased harmful oxidative stress markers in the brain, while longer exposures (60 minutes) triggered protective adaptation responses. This suggests that magnetic field exposure duration significantly affects how the brain responds to electromagnetic stress.

Why This Matters

This study reveals a critical finding about dose-response relationships in EMF exposure that challenges simplistic assumptions about magnetic field safety. The 7 mT exposure level used here is substantially higher than typical household magnetic fields (which measure in microTesla), but it's within the range of some therapeutic magnetic devices and certain occupational exposures. What makes this research particularly significant is the demonstration that the brain's response to magnetic fields isn't linear - shorter exposures caused oxidative damage while longer ones triggered adaptation. This finding adds to the growing body of evidence showing that EMF effects depend heavily on exposure parameters, not just field strength. The reality is that our understanding of how different exposure durations affect biological systems remains incomplete, yet regulatory standards often ignore these nuanced dose-response relationships.

Exposure Details

Magnetic Field
7 mG
Source/Device
40 Hz
Exposure Duration
30 min/day for 10 days & 60 min/day for 10 days

Exposure Context

This study used 7 mG 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 ContextA logarithmic scale showing exposure levels relative to Building Biology concern thresholds and regulatory limits.Study Exposure Level in ContextThis study: 7 mGExtreme Concern5 mGFCC Limit2,000 mGEffects observed in the Extreme Concern range (Building Biology)FCC limit is 286x higher than this exposure level

Study Details

The aim of the study is to assess the effect of ELF-MF parameters most frequently used in magnetotherapy on reactive oxygen species generation (ROS) in brain tissue of experimental animals depending on the time of exposure to this field.

The research material included adult male Sprague-Dawley rats, aged 3-4 months. The animals were div...

ELF-MF parameters of 7 mT, 40 Hz, 30 min/day for 10 days caused a significant increase in lipid per...

The effect of ELF-MF irradiation on oxidative stress parameters depends on the time of animal exposure to magnetic field.

Cite This Study
Ciejka E, Kleniewska P, Skibska B, Goraca A (2011). Effects of extremely low frequency magnetic field on oxidative balance in brain of rats J Physiol Pharmacol. 62(6):657-661, 2011.
Show BibTeX
@article{e_2011_effects_of_extremely_low_337,
  author = {Ciejka E and Kleniewska P and Skibska B and Goraca A},
  title = {Effects of extremely low frequency magnetic field on oxidative balance in brain of rats},
  year = {2011},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/22314568/},
}

Quick Questions About This Study

Researchers exposed rats to 40 Hz magnetic fields at 7 mT (milliTesla) for either 30 or 60 minutes daily over 10 days to study brain cell damage. They found that shorter exposures (30 minutes) increased harmful oxidative stress markers in the brain, while longer exposures (60 minutes) triggered protective adaptation responses. This suggests that magnetic field exposure duration significantly affects how the brain responds to electromagnetic stress.