Effects of cellular phone use on ear canal temperature measured by NTC thermistors.
Tahvanainen K, Nino J, Halonen P, Kuusela T, Alanko T, Laitinen T, Lansimies E, Hietanen M, Lindholm H. · 2007
View Original AbstractCell phones heat ear canal tissue by over 1°C during typical 35-minute calls, with warming persisting after use.
Plain English Summary
Finnish researchers measured ear canal temperature in 30 people during 35-minute cell phone calls using both 900 MHz and 1800 MHz phones. They found that ear temperatures increased by more than 1 degree Celsius during phone use compared to sham exposure, with the warming effect persisting even after the call ended. The researchers concluded this heating came from the phone's battery warming up during maximum power use, not from the radiofrequency fields themselves.
Why This Matters
This study provides clear evidence that cell phones cause measurable heating in the ear canal during typical use, with temperature increases of over 1 degree Celsius that persist after the call ends. What makes this research particularly valuable is its rigorous double-blind, placebo-controlled design using 30 subjects and precise temperature monitoring throughout 35-minute exposures. While the researchers attribute the heating to battery warmth rather than RF fields, the practical reality remains the same: your ear is getting heated during phone calls. The science demonstrates that this thermal effect is real and measurable, occurring at power levels your phone uses during normal operation. Put simply, every time you hold your phone to your ear for extended periods, you're exposing that tissue to temperature increases that exceed what occurs naturally in your body.
Exposure Information
Specific exposure levels were not quantified in this study. The study examined exposure from: 900 or 1800 MHz cellular phone Duration: 35-min
Study Details
The earlier studies using phantom models and human subjects concerning warming effects during cellular phone use have been controversial, partly because radiofrequency (RF) exposures have been variable. In this randomized, double-blind, placebo-controlled crossover trial, 30 healthy subjects were submitted to 900 MHz (2W) and 1800 MHz (1W) cellular phone RF exposure, and to sham exposure in separate study sessions.
Temperature signals were recorded continuously in both ear canals before, during and after the 35-mi...
Temperatures in the exposed ear were significantly higher during RF exposures compared with sham exp...
The results of this study suggest that RF exposure to a cellular phone, either using 900 or 1800 MHz with their maximal allowed antenna powers, increases the temperature in the ear canal. The reason for the ear canal temperature rising is a consequence of mobile phone battery warming during maximal antenna power use. The earlier published articles do not indicate that temperature rising in the ear canal has any significant contribution from the RF fields emitted from mobile phones.
Show BibTeX
@article{k_2007_effects_of_cellular_phone_2616,
author = {Tahvanainen K and Nino J and Halonen P and Kuusela T and Alanko T and Laitinen T and Lansimies E and Hietanen M and Lindholm H. },
title = {Effects of cellular phone use on ear canal temperature measured by NTC thermistors.},
year = {2007},
url = {https://pubmed.ncbi.nlm.nih.gov/17445067/},
}