1439 MHz pulsed TDMA fields affect performance of rats in a T-maze task only when body temperature is elevated.
Yamaguchi H, Tsurita G, Ueno S, Watanabe S, Wake K, Taki M, Nagawa H. · 2003
View Original AbstractCell phone radiation impaired rat learning only when exposure was high enough to cause tissue heating, not at levels four times above phone limits.
Plain English Summary
Researchers exposed rats to cell phone-type radiation (1439 MHz) while testing their ability to learn and remember food locations in a maze. They found that only the highest exposure levels - which caused body temperature to rise - impaired the rats' learning performance. At exposure levels about four times stronger than typical cell phones (but without heating effects), no learning problems occurred.
Why This Matters
This study provides important context for understanding when EMF exposure might affect cognitive function. The key finding is that learning impairment occurred only when radiation exposure was intense enough to heat body tissue - a threshold effect that suggests thermal mechanisms rather than non-thermal biological impacts. However, we should note the exposure levels tested here. The 'safe' level that showed no effects (7.5 W/kg to the brain) was still nearly four times higher than current cell phone limits. What this means for you is that while this particular study didn't find cognitive effects at moderately elevated exposure levels, it doesn't rule out subtler impacts from chronic, lower-level exposures that characterize real-world cell phone use. The research also focused on acute learning tasks rather than long-term cognitive development or more complex brain functions.
Exposure Details
- SAR
- 1.7, 7.5 W/kg
- Source/Device
- 1439 MHz
- Exposure Duration
- 1 h daily for 4 days or for 4 weeks t
Exposure Context
This study used 1.7, 7.5 W/kg for SAR (device absorption):
- 4.3x above the Building Biology guideline of 0.4 W/kg
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 Details
This study sought to clarify the effects of exposure to electromagnetic waves (EMW) used in cellular phones on learning and memory processes.
Sprague-Dawley rats were exposed for either 1 h daily for 4 days or for 4 weeks to a pulsed 1439 MHz...
The animals exposed to EMW with the brain average SAR of 25 W/kg for 4 days showed statistically sig...
These results suggest that the exposure to a TDMA field at levels about four times stronger than emitted by cellular phones does not affect the learning and memory processes when there are no thermal effects.
Show BibTeX
@article{h_2003_1439_mhz_pulsed_tdma_1442,
author = {Yamaguchi H and Tsurita G and Ueno S and Watanabe S and Wake K and Taki M and Nagawa H.},
title = {1439 MHz pulsed TDMA fields affect performance of rats in a T-maze task only when body temperature is elevated.},
year = {2003},
url = {https://pubmed.ncbi.nlm.nih.gov/12696082/},
}