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Cellular Effects

Effects of continuous and intermittent exposure to RF fields with a wide range of SARs on cell growth, survival, and cell cycle distribution.

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Takashima Y, Hirose H, Koyama S, Suzuki Y, Taki M, Miyakoshi J · 2006

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Cell damage occurred only at extremely high RF exposure levels (200+ W/kg) that cause significant heating, far above typical device limits.

Plain English Summary

Summary written for general audiences

Japanese researchers exposed cells to 2.45 GHz radiation (WiFi frequency) at different power levels. Cell growth remained normal up to 100 W/kg, but died at 200 W/kg when temperatures exceeded 104°F, showing cellular damage occurs only from significant heating effects.

Why This Matters

This study provides important context for understanding EMF safety thresholds, particularly because it tested exposure levels spanning from extremely low (0.05 W/kg) to extraordinarily high (1500 W/kg). The researchers found a clear thermal threshold at 200 W/kg where cell damage began occurring. What this means for you is reassuring in one sense: typical consumer devices operate at much lower SAR levels (cell phones are limited to 1.6 W/kg in the US). However, the study's focus on thermal effects doesn't address the growing body of research showing biological changes at much lower, non-thermal exposure levels. The reality is that while this research suggests high-intensity RF exposure causes damage through heating, it doesn't rule out subtler biological effects from the chronic, lower-level exposures we experience daily from wireless devices.

Exposure Details

SAR
0.05 to 1500 W/kg
Source/Device
2.45 GHz
Exposure Duration
2 h

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 0.05 to 1500 W/kgExtreme Concern - 0.1 W/kgFCC Limit - 1.6 W/kgEffects observed in the Severe Concern rangeFCC limit is 32x higher than this level
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 2.45 GHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 2.45 GHzPower lines50/60 Hz5G mm28 GHzLogarithmic scale

Study Details

To examine the biological effects of radio frequency (RF) electromagnetic fields in vitro, we have examined the fundamental cellular responses, such as cell growth, survival, and cell cycle distribution, following exposure to a wide range of specific absorption rates (SAR).

Furthermore, we compared the effects of continuous and intermittent exposure at high SARs. An RF ele...

When cells were exposed to a continuous RF field at SARs from 0.05 to 100 W/kg for 2 h, cellular gro...

Exposure to RF radiation results in heating of the medium, and the thermal effect depends on the mean SAR. Hence, these results suggest that the proliferation disorder is caused by the thermal effect.

Cite This Study
Takashima Y, Hirose H, Koyama S, Suzuki Y, Taki M, Miyakoshi J (2006). Effects of continuous and intermittent exposure to RF fields with a wide range of SARs on cell growth, survival, and cell cycle distribution. Bioelectromagnetics.27(5):392-400, 2006.
Show BibTeX
@article{y_2006_effects_of_continuous_and_1349,
  author = {Takashima Y and Hirose H and Koyama S and Suzuki Y and Taki M and Miyakoshi J},
  title = {Effects of continuous and intermittent exposure to RF fields with a wide range of SARs on cell growth, survival, and cell cycle distribution.},
  year = {2006},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/16615058/},
}
PubMed: 16615058

Cited By (46 papers)

View all 46 citing papers on Semantic Scholar

Quick Questions About This Study

Japanese researchers found that 2.45 GHz radiation (WiFi frequency) killed cells only at 200 W/kg, when temperatures exceeded 104°F. Cell growth remained completely normal at all lower power levels up to 100 W/kg, indicating cellular damage occurs only from significant heating effects.
No, intermittent 2.45 GHz radiation at peak levels up to 1500 W/kg caused no additional cellular damage compared to continuous exposure at the same average power. The study found that mean SAR levels, not peak levels, determine biological effects.
Cells died when 2.45 GHz radiation heated their surrounding medium to 44.1°C (111°F) at 200 W/kg exposure levels. Lower temperatures of 39.1°C and 41.0°C from 50 and 100 W/kg exposures respectively caused no cellular damage or growth changes.
No, this 2006 Japanese study found that 2.45 GHz radiation had no effect on cell cycle distribution or cellular growth at any power level that didn't cause significant heating. All biological effects were attributed to thermal heating of the cell medium.
Yes, continuous 2-hour exposure to 2.45 GHz radiation at 100 W/kg showed no effects on cellular growth, survival, or cell cycle distribution. Japanese researchers concluded that cellular damage only occurs at much higher levels that cause significant heating above normal body temperature.