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Acute dosimetry and estimation of threshold inducing behavioral signs of thermal stress in rabbits at 2.45-GHz microwave exposure.

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Hirata A, Kojima M, Kawai H, Yamashiro Y, Watanabe S, Sasaki H, Fujiwara O. · 2010

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Microwave radiation at 1.3 W/kg causes measurable thermal stress in animals, validating current safety limits for WiFi-frequency exposures.

Plain English Summary

Summary written for general audiences

Researchers exposed rabbits to 2.45-GHz microwave radiation (WiFi frequency) to find thermal stress thresholds. When core body temperature rose just 1°C, rabbits showed clear distress behaviors at 1.3 W/kg exposure levels, helping establish microwave safety limits for humans.

Why This Matters

This research provides crucial data for understanding thermal thresholds in microwave exposure, directly informing the safety standards that govern our daily technology use. The 2.45-GHz frequency tested is identical to what your WiFi router and microwave oven emit, making these findings immediately relevant to everyday exposures. What's particularly significant is that the 1.3 W/kg SAR threshold identified here is close to current regulatory limits for localized exposure (2 W/kg in many countries). The study demonstrates that even a modest 1-degree temperature increase triggers measurable biological stress responses, reinforcing that thermal effects remain the primary concern for microwave frequency exposures. While your typical WiFi device operates at much lower power levels than those tested, this research helps validate the biological basis for existing safety standards and reminds us why maintaining distance from high-powered microwave sources remains important.

Exposure Details

SAR
1.3 W/kg
Power Density
10, 100 µW/m²
Source/Device
2.45-GHz

Exposure Context

This study used 10, 100 µW/m² for radio frequency:

This study used 1.3 W/kg for SAR (device absorption):

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: 10, 100 µW/m²Extreme Concern1,000 uW/m2FCC Limit10M uW/m2Effects observed in the Severe Concern range (Building Biology)FCC limit is 1,000,000x higher than this exposure level

Study Details

The aim of this study is to investigate Acute dosimetry and estimation of threshold inducing behavioral signs of thermal stress in rabbits at 2.45-GHz microwave exposure.

In the present study, we performed experiments on rabbits exposed to 2.45-GHz MWs. A total of 24 mea...

Our experimental results suggest that a core temperature elevation of 1 degrees C is an estimate of ...

The whole-body average SAR required for MW-induced behavioral sign in rabbits was estimated as approximately 1.3 W/kg for 2.45-GHz MWs.

Cite This Study
Hirata A, Kojima M, Kawai H, Yamashiro Y, Watanabe S, Sasaki H, Fujiwara O. (2010). Acute dosimetry and estimation of threshold inducing behavioral signs of thermal stress in rabbits at 2.45-GHz microwave exposure. IEEE Trans Biomed Eng. 57(5):1234-42, 2010.
Show BibTeX
@article{a_2010_acute_dosimetry_and_estimation_1027,
  author = {Hirata A and Kojima M and Kawai H and Yamashiro Y and Watanabe S and Sasaki H and Fujiwara O.},
  title = {Acute dosimetry and estimation of threshold inducing behavioral signs of thermal stress in rabbits at 2.45-GHz microwave exposure.},
  year = {2010},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/20172806/},
}

Quick Questions About This Study

Researchers exposed rabbits to 2.45-GHz microwave radiation (WiFi frequency) to find thermal stress thresholds. When core body temperature rose just 1°C, rabbits showed clear distress behaviors at 1.3 W/kg exposure levels, helping establish microwave safety limits for humans.