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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 tissue showed oxidative damage from 30-minute magnetic field exposures but adapted to 60-minute exposures, revealing complex dose-response relationships.

Plain English Summary

Summary written for general audiences

Polish researchers exposed rats to 7 milliTesla magnetic fields at 40 Hz (similar to some therapeutic magnetic devices) for either 30 or 60 minutes daily over 10 days. They found that 30-minute exposures increased oxidative stress markers in brain tissue, indicating cellular damage from free radicals. However, 60-minute exposures triggered adaptive mechanisms that appeared to protect against this damage, suggesting the brain can develop tolerance to longer magnetic field exposures.

Why This Matters

This study reveals a critical nuance in how magnetic field exposure affects brain health that most research overlooks: duration matters enormously. The finding that shorter exposures (30 minutes) caused oxidative stress while longer exposures (60 minutes) triggered protective adaptation challenges the simple assumption that more exposure always equals more harm. The 7 milliTesla exposure level used here is significantly higher than typical household magnetic fields (which measure in microTesla), but comparable to therapeutic magnetic devices used in clinical settings. What this means for you is that the biological response to magnetic fields isn't linear or predictable. The brain's ability to adapt to longer exposures doesn't necessarily make them safe, and the oxidative stress from shorter exposures raises questions about cumulative effects from intermittent magnetic field exposure in our daily environment.

Exposure Details

Magnetic Field
7 mG
Source/Device
40 Hz
Exposure Duration
30 min/day, 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 pero...

The study has shown that ELF-MF applied for 30 min/day for 10 days can affect free radical generation in the brain. Prolongation of the exposure to ELF-MF (60/min/day) caused adaptation to this field. 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_231,
  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://www.researchgate.net/profile/Anna-Goraca/publication/221814778_Effect_of_extremely_low_frequency_magnetic_field_on_oxidative_balance_in_brain_of_rats/links/542909a10cf26120b7b57a8b/Effect-of-extremely-low-frequency-magnetic-field-on-oxidative-balance-in-brain-of-rats.pdf},
}

Quick Questions About This Study

Polish researchers exposed rats to 7 milliTesla magnetic fields at 40 Hz (similar to some therapeutic magnetic devices) for either 30 or 60 minutes daily over 10 days. They found that 30-minute exposures increased oxidative stress markers in brain tissue, indicating cellular damage from free radicals. However, 60-minute exposures triggered adaptive mechanisms that appeared to protect against this damage, suggesting the brain can develop tolerance to longer magnetic field exposures.