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Physiological changes in rats after exposure to low levels of microwaves.

Bioeffects Seen

Ray S, Behari J · 1990

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Low-level microwave exposure triggered stress responses in rats, causing reduced appetite and altered organ function at power levels comparable to some wireless devices.

Plain English Summary

Summary written for general audiences

Researchers exposed rats to low-level microwave radiation (7.5 GHz) for 3 hours daily over 60 days and found significant physiological changes. The exposed animals ate and drank less, gained less weight, and showed altered blood parameters and organ weights compared to unexposed controls. The scientists concluded these changes represented a stress response triggered by microwave exposure affecting the central nervous system.

Why This Matters

This 1990 study demonstrates that even relatively low-level microwave exposure can trigger measurable physiological stress responses in living organisms. The power density used (0.6 mW/cm2) is within the range of some everyday wireless devices, though the specific frequency and modulation pattern differ from typical consumer electronics. What makes this research particularly significant is that it shows systemic effects throughout the body - not just localized heating - suggesting that EMF exposure can influence fundamental biological processes through the nervous system. The study's finding of reduced food and water intake, along with altered organ weights and blood parameters, points to EMF acting as a biological stressor that the body must work to compensate for over time.

Exposure Details

Power Density
0.6 µW/m²
Source/Device
7.5-GHz
Exposure Duration
3 h daily for 60 days

Exposure Context

This study used 0.6 µW/m² for radio frequency:

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: 0.6 µW/m²Extreme Concern1,000 uW/m2FCC Limit10M uW/m2Effects observed in the Slight Concern range (Building Biology)FCC limit is 16,666,667x higher than this exposure level

Study Details

The effects of exposure to sublethal levels of microwaves were studied.

Young albino rats of both sexes were exposed for 60 days to 7.5-GHz microwaves (1.0-KHz square wave ...

It was found that the animals exposed to microwaves tended to eat and drink less and thus showed a s...

Cite This Study
Ray S, Behari J (1990). Physiological changes in rats after exposure to low levels of microwaves. Radiat Res 123(2):199-202, 1990.
Show BibTeX
@article{s_1990_physiological_changes_in_rats_1290,
  author = {Ray S and Behari J},
  title = {Physiological changes in rats after exposure to low levels of microwaves.},
  year = {1990},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/2389006/},
}

Quick Questions About This Study

Researchers exposed rats to low-level microwave radiation (7.5 GHz) for 3 hours daily over 60 days and found significant physiological changes. The exposed animals ate and drank less, gained less weight, and showed altered blood parameters and organ weights compared to unexposed controls. The scientists concluded these changes represented a stress response triggered by microwave exposure affecting the central nervous system.