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

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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 ContextStudy Exposure Level in ContextThis study: 0.6 µW/m²Extreme Concern - 1,000 uW/m2FCC Limit - 10M uW/m2Effects observed in the Slight Concern rangeFCC limit is 16,666,667x higher than this level
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 7.50 GHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 7.50 GHzPower lines50/60 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

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/},
}
PubMed: 2389006

Cited By (54 papers)

View all 54 citing papers on Semantic Scholar

Quick Questions About This Study

Yes, research shows microwave radiation can affect weight gain. A 1990 study found rats exposed to 7.5 GHz microwaves for 60 days ate less food, drank less water, and gained significantly less weight than unexposed animals.
Research indicates microwave exposure can reduce appetite. Scientists exposed rats to low-level microwave radiation and observed the animals consistently ate and drank less than control groups, suggesting microwaves may suppress normal feeding behaviors.
Studies suggest microwave radiation can alter blood parameters. Researchers found significant changes in blood measurements in rats exposed to 7.5 GHz microwaves, indicating potential impacts on hematological function and overall physiological health.
Research indicates microwave exposure triggers stress responses through the central nervous system. A 60-day study found physiological changes in exposed rats that scientists attributed to nervous system-mediated stress reactions from microwave radiation.
Low-level microwave exposure can cause physiological stress responses, including reduced appetite, altered blood parameters, and changed organ weights. Research shows these effects occur even at power levels previously considered safe.