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Exposure to pulse-modulated radio frequency electromagnetic fields affects regional cerebral blood flow.

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Huber R, Treyer V, Schuderer J, Berthold T, Buck A, Kuster N, Landolt HP, Achermann P. · 2005

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Cell phone radiation measurably increases brain blood flow within 30 minutes at exposure levels considered 'safe' by current standards.

Plain English Summary

Summary written for general audiences

Swiss researchers exposed 12 healthy men to cell phone-like radio frequency radiation for 30 minutes and used brain scans to measure blood flow changes. They found that exposure increased blood flow in the brain's frontal cortex, but only when the signal was pulse-modulated like actual cell phones (not steady signals like cell towers). This demonstrates that cell phone radiation can measurably alter brain activity within just 30 minutes of exposure.

Why This Matters

This study provides compelling evidence that cell phone radiation creates measurable biological changes in the human brain. The researchers used positron emission tomography (PET) scans to document increased blood flow in brain regions responsible for executive function and decision-making. What makes this finding particularly significant is that the exposure level (1 W/kg SAR) falls within current safety limits and represents typical cell phone use. The fact that only pulse-modulated signals affected brain blood flow supports growing evidence that the pulsing nature of digital wireless signals, not just their power level, drives biological effects. This research adds to a substantial body of evidence showing that current safety standards, which only consider heating effects, fail to account for the complex ways wireless radiation interacts with living tissue.

Exposure Details

SAR
1 W/kg
Source/Device
900 MHz
Exposure Duration
30 minutes

Exposure Context

This study used 1 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: 1 W/kgExtreme Concern0.1 W/kgFCC Limit1.6 W/kgEffects observed in the Extreme Concern range (Building Biology)FCC limit is 2x higher than this exposure level

Study Details

We investigated the effects of radio frequency electromagnetic fields (RF EMF) similar to those emitted by mobile phones on waking regional cerebral blood flow (rCBF) in 12 healthy young men.

Two types of RF EMF exposure were applied: a 'base-station-like' and a 'handset-like' signal. Positr...

We observed an increase in relative rCBF in the dorsolateral prefrontal cortex on the side of exposu...

This finding supports our previous observation that pulse modulation of RF EMF is necessary to induce changes in the waking and sleep EEG, and substantiates the notion that pulse modulation is crucial for RF EMF-induced alterations in brain physiology.

Cite This Study
Huber R, Treyer V, Schuderer J, Berthold T, Buck A, Kuster N, Landolt HP, Achermann P. (2005). Exposure to pulse-modulated radio frequency electromagnetic fields affects regional cerebral blood flow. Eur J Neurosci. 21(4):1000-1006, 2005.
Show BibTeX
@article{r_2005_exposure_to_pulsemodulated_radio_1038,
  author = {Huber R and Treyer V and Schuderer J and Berthold T and Buck A and Kuster N and Landolt HP and Achermann P.},
  title = {Exposure to pulse-modulated radio frequency electromagnetic fields affects regional cerebral blood flow.},
  year = {2005},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/15787706/},
}

Quick Questions About This Study

Swiss researchers exposed 12 healthy men to cell phone-like radio frequency radiation for 30 minutes and used brain scans to measure blood flow changes. They found that exposure increased blood flow in the brain's frontal cortex, but only when the signal was pulse-modulated like actual cell phones (not steady signals like cell towers). This demonstrates that cell phone radiation can measurably alter brain activity within just 30 minutes of exposure.