3,138 Studies Reviewed. 77.4% Found Biological Effects. The Evidence is Clear.

Thresholds of microwave-evoked warmth sensations in human skin.

Bioeffects Seen

Blick DW, Adair ER, Hurt WD, Sherry CJ, Walters TJ, Merritt JH · 1997

View Original Abstract
Share:

Human skin detects 94 GHz microwave energy at power levels 10 times lower than microwave oven frequencies, suggesting current safety standards may be inadequate.

Plain English Summary

Summary written for general audiences

Researchers tested how much microwave energy triggers warmth sensations on human skin at different frequencies. Higher frequency microwaves (94 GHz) required ten times less power than microwave oven frequencies (2.45 GHz) to produce warmth, showing skin sensitivity increases dramatically with frequency.

Why This Matters

This study reveals a critical aspect of how our bodies respond to microwave radiation that has significant implications for 5G and millimeter wave technologies. The research demonstrates that at 94 GHz-a frequency being deployed in 5G networks-human skin detects thermal effects at just 4.5 mW/cm2, compared to 63.1 mW/cm2 at 2.45 GHz. Put simply, your body becomes dramatically more sensitive to microwave energy as frequencies increase into the ranges now being used for wireless communications. What this means for you is that the 'thermal-only' safety standards currently used to regulate wireless devices may be inadequate for higher frequency exposures. These standards assume that only heating effects matter, but this study shows our bodies can detect and respond to much lower power levels at higher frequencies than previously considered in safety calculations.

Exposure Details

Power Density
4.5 ± 0.6 µW/m²
Source/Device
94 GHz
Exposure Duration
10 seconds

Exposure Context

This study used 4.5 ± 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: 4.5 ± 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

We measured thresholds for microwave-evoked skin sensations of warmth at frequencies of 2.45, 7.5, 10, 35, and 94 GHz.

In the same subjects, thresholds of warmth evoked by infrared radiation (IR) were also measured for ...

Sensitivity increased monotonically with frequency throughout the range of microwave frequencies tes...

Cite This Study
Blick DW, Adair ER, Hurt WD, Sherry CJ, Walters TJ, Merritt JH (1997). Thresholds of microwave-evoked warmth sensations in human skin. Bioelectromagnetics 18(6):403-409, 1997.
Show BibTeX
@article{dw_1997_thresholds_of_microwaveevoked_warmth_863,
  author = {Blick DW and Adair ER and Hurt WD and Sherry CJ and Walters TJ and Merritt JH},
  title = {Thresholds of microwave-evoked warmth sensations in human skin.},
  year = {1997},
  
  url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/(SICI)1521-186X(1997)18:6%3C403::AID-BEM1%3E3.0.CO;2-6},
}

Quick Questions About This Study

Researchers tested how much microwave energy triggers warmth sensations on human skin at different frequencies. Higher frequency microwaves (94 GHz) required ten times less power than microwave oven frequencies (2.45 GHz) to produce warmth, showing skin sensitivity increases dramatically with frequency.