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Chronic exposure to low-intensity magnetic field improves acquisition and maintenance of memory.

Bioeffects Seen

Liu T, Wang S, He L, Ye K. · 2008

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Chronic exposure to 2 mT magnetic fields improved rat memory performance, showing EMF brain effects are more complex than previously understood.

Plain English Summary

Summary written for general audiences

Researchers exposed rats to extremely low frequency magnetic fields (similar to power lines) for 4 weeks and found the animals performed better on memory tests. The exposed rats learned spatial tasks faster and retained memories longer than unexposed rats. This unexpected finding suggests that certain EMF exposures might enhance rather than impair brain function under specific conditions.

Why This Matters

This study presents an intriguing counterpoint to the typical narrative around EMF health effects. The researchers found that 2 milliTesla magnetic fields at 50 Hz actually improved spatial learning and memory retention in rats. To put this in perspective, 2 mT is significantly higher than typical household exposures (which are usually measured in microTesla), but within ranges found near high-voltage power lines or certain industrial equipment. What this means for you is that EMF effects on the brain appear more complex than simple harm or safety. The research demonstrates that biological responses to electromagnetic fields depend heavily on exposure parameters like frequency, intensity, and duration. While this single study shouldn't change safety recommendations, it highlights why we need more nuanced research rather than blanket assumptions about EMF effects.

Exposure Details

Magnetic Field
2 mG
Source/Device
50 Hz
Exposure Duration
1 or 4 h for 4 weeks

Exposure Context

This study used 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: 2 mGExtreme Concern5 mGFCC Limit2,000 mGEffects observed in the Severe Concern range (Building Biology)FCC limit is 1,000x higher than this exposure level

Study Details

In this study, we examined the changes in spatial learning and memory by the Morris water maze test after 4 weeks of daily exposure of rats to a 50-Hz magnetic field of 2 mT for either 1 or 4 h.

We found that chronic exposure to ELF MF reduced the latency to find the hidden platform and improve...

These findings for the first time indicate that chronic exposure to ELF MF exerts a positive effect on the acquisition and maintenance of spatial memory

Cite This Study
Liu T, Wang S, He L, Ye K. (2008). Chronic exposure to low-intensity magnetic field improves acquisition and maintenance of memory. Neuroreport. 19(5):549-552, 2008b.
Show BibTeX
@article{t_2008_chronic_exposure_to_lowintensity_276,
  author = {Liu T and Wang S and He L and Ye K.},
  title = {Chronic exposure to low-intensity magnetic field improves acquisition and maintenance of memory.},
  year = {2008},
  
  url = {https://journals.lww.com/neuroreport/Abstract/2008/03260/Chronic_exposure_to_low_intensity_magnetic_field.8.aspx},
}

Quick Questions About This Study

Researchers exposed rats to extremely low frequency magnetic fields (similar to power lines) for 4 weeks and found the animals performed better on memory tests. The exposed rats learned spatial tasks faster and retained memories longer than unexposed rats. This unexpected finding suggests that certain EMF exposures might enhance rather than impair brain function under specific conditions.