Exposure to the radiofrequency fields generated by mobile phones does not cause headache or increase blood pressure. Most people who experience such symptoms do so because they expect that they will occur. Researchers from the Norway University of Science and Technology in Trondheim recruited 17 subjects who regularly experienced pain or discomfort in the head during or shortly after mobile phone calls lasting between 15 and 30 minutes. The participants were tested during mobile phone radiofrequency exposure and sham exposure, without knowing which session was which. Each session lasted 30 minutes, and 65 pairs of trials were conducted. It was found that the subjects said they felt an increase in pain or discomfort during 68 percent of all trials. The degree of symptoms was not associated with the order of trials. The researchers observed no statistically significant correlations between actual exposures and the subjects' reports of symptom severity, and no effects of exposure on changes in heart rate or blood pressure. The findings conclude that the most likely explanation for the headaches and discomfort reported by the subjects is that the symptoms are due to negative expectations.
Cephalalgia,
May 2007