Tahvanainen K, Nino J, Halonen P, Kuusela T, et al. (2004)
Thirty-two subjects (18 male) participated in the study, which was designed to test the effect of RF radiation on blood pressure (BP) and heart rate (HR). Double randomization was carried out. The first randomization was to pre-define the order of the RF exposures to either 900 or 1800 MHz, one week apart. The second was to pre-define the order of treatments to either RF or sham exposure.
Each subject wore a plastic helmet, with the active phone leaning to the ear on the dominant side of the head, and an identical but inactive phone on the other side. The estimated SAR was 1.58 W/kg for the 900 MHz phone and 0.70 W/kg for the 1800 MHz phone.
During each test session, the subjects were exposed to 35 minutes of RF exposure and 35 minutes of sham exposure. Initially, before any exposure, each subject underwent monitoring of BP and HR while undergoing different breathing and other manoeuvres designed to test the autonomic nervous system. After the exposure, these manoeuvres were repeated, with similar monitoring of BP and HR
The results showed that BP and HR did not change significantly during or after the 35-minute RF exposures at 900 MHz or 1800 MHz, compared to sham exposure.