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Effects of extremely low frequency magnetic field on anxiety level and spatial memory of adult rats.

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He LH, Shi HM, Liu TT, Xu YC, Ye KP, Wang S. · 2011

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Power-frequency magnetic fields caused anxiety while improving memory in rats, showing EMF can simultaneously harm and enhance different brain functions.

Plain English Summary

Summary written for general audiences

Researchers exposed adult rats to 50-Hz magnetic fields (the same frequency as power lines) for either 1 or 4 hours daily over 4 weeks. They found that rats exposed for 4 hours showed increased anxiety-like behaviors but also improved spatial learning and long-term memory. This suggests that extremely low frequency magnetic fields can affect both emotional and cognitive brain functions, even at relatively short daily exposure periods.

Why This Matters

This study reveals a complex picture of how power-frequency magnetic fields affect the brain. The 2 mT exposure level used here is significantly higher than typical household exposures (which range from 0.01-0.1 mT), but it's within the range that occupational workers or people living very close to power lines might experience. What makes this research particularly noteworthy is the dual finding: the same EMF exposure that caused anxiety also enhanced certain types of memory. This contradicts the simple narrative that EMF effects are either all harmful or all beneficial. The science demonstrates that electromagnetic fields can alter brain function in measurable ways, with effects that vary depending on the specific brain system involved. The fact that anxiety increased while spatial memory improved suggests these fields are acting on different neural pathways. What this means for you is that EMF exposure isn't just about whether effects exist, but about understanding which effects occur at which exposure levels and durations.

Exposure Details

Magnetic Field
2 mG
Source/Device
50-Hz
Exposure Duration
1 hour and 4 hours 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

The present study examined the effects of chronic exposure to ELF MF on anxiety level and spatial memory of adult rats.

The 50-Hz ELF MF was used during the whole experimental procedures and the value of magnetic field (...

Rats in MF 4 hours group had increased anxiety-like behaviors with unaltered locomotor activity. In ...

Chronic ELF MF exposure has anxiogenic effect on rats, and the promoting effects on spatial learning and long-term retention of spatial memory.

Cite This Study
He LH, Shi HM, Liu TT, Xu YC, Ye KP, Wang S. (2011). Effects of extremely low frequency magnetic field on anxiety level and spatial memory of adult rats. Chin Med J (Engl). 124(20):3362-3366, 2011.
Show BibTeX
@article{lh_2011_effects_of_extremely_low_651,
  author = {He LH and Shi HM and Liu TT and Xu YC and Ye KP and Wang S.},
  title = {Effects of extremely low frequency magnetic field on anxiety level and spatial memory of adult rats.},
  year = {2011},
  
  url = {https://journals.lww.com/cmj/Fulltext/2011/10020/Effects_of_extremely_low_frequency_magnetic_field.28.aspx},
}

Quick Questions About This Study

Researchers exposed adult rats to 50-Hz magnetic fields (the same frequency as power lines) for either 1 or 4 hours daily over 4 weeks. They found that rats exposed for 4 hours showed increased anxiety-like behaviors but also improved spatial learning and long-term memory. This suggests that extremely low frequency magnetic fields can affect both emotional and cognitive brain functions, even at relatively short daily exposure periods.