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Changes in human EEG alpha activity following exposure to two different pulsed magnetic field sequences.

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Cook CM, Saucier DM, Thomas AW, Prato FS. · 2009

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Everyday magnetic field exposure altered human brain waves within 5 minutes, showing our brains actively respond to EMF levels considered safe.

Plain English Summary

Summary written for general audiences

Researchers exposed 32 people to weak pulsed magnetic fields (the type generated by power lines and electrical devices) for 15 minutes while measuring their brain waves. They found that different pulse patterns altered alpha brain wave activity in the back regions of the brain within just 5 minutes of exposure. The changes persisted even after exposure ended, suggesting that these everyday magnetic fields can measurably affect brain function.

Why This Matters

This study provides clear evidence that extremely low frequency magnetic fields at everyday exposure levels can alter human brain activity. The magnetic field strength used (200 microTesla) is well within the range you encounter from common household appliances and power lines. What makes this research particularly significant is that brain wave changes occurred within just 5 minutes of exposure and persisted afterward. The study also found that previous exposures influenced how the brain responded to subsequent magnetic field exposure, suggesting potential cumulative effects. This adds to a growing body of evidence showing that the brain is sensitive to EMF exposure at levels regulatory agencies currently consider safe. While we don't yet know the long-term health implications of these brain wave changes, the research demonstrates that our nervous systems are clearly responding to the electromagnetic environment we've created around ourselves.

Exposure Details

Magnetic Field
0.2 mG
Source/Device
0–500 Hz
Exposure Duration
15 min

Exposure Context

This study used 0.2 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: 0.2 mGExtreme Concern5 mGFCC Limit2,000 mGEffects observed in the Slight Concern range (Building Biology)FCC limit is 10,000x higher than this exposure level

Study Details

The present study investigates the effects of a weak (+/-200 microT(pk)), pulsed, extremely low frequency magnetic field (ELF MF) upon the human electroencephalogram (EEG).

In the present study, subjects (n = 32) were exposed to two different pulsed MF sequences (1 and 2, ...

Results suggest that compared to sham exposure, alpha activity was lowered over the occipital–pariet...

This study supports our previous observation of EEG changes after 5 min pulsed ELF MF exposure. The results of this study are also consistent with existing EEG experiments of ELF MF and mobile phone effects upon the brain.

Cite This Study
Cook CM, Saucier DM, Thomas AW, Prato FS. (2009). Changes in human EEG alpha activity following exposure to two different pulsed magnetic field sequences. Bioelectromagnetics. 30(1):9-20, 2009.
Show BibTeX
@article{cm_2009_changes_in_human_eeg_233,
  author = {Cook CM and Saucier DM and Thomas AW and Prato FS.},
  title = {Changes in human EEG alpha activity following exposure to two different pulsed magnetic field sequences.},
  year = {2009},
  doi = {10.1002/bem.20434},
  url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/bem.20434},
}

Quick Questions About This Study

Researchers exposed 32 people to weak pulsed magnetic fields (the type generated by power lines and electrical devices) for 15 minutes while measuring their brain waves. They found that different pulse patterns altered alpha brain wave activity in the back regions of the brain within just 5 minutes of exposure. The changes persisted even after exposure ended, suggesting that these everyday magnetic fields can measurably affect brain function.