ID Number		149
Study Type		Human / Provocation
Model		900 MHz (GSM) exposure to humans and analysis of blood pressure
Details		Human subjects (n=10) were exposed to 900 MHz (GSM) from a cellular telephone fixed to the right side of the head at a maximal 2 watt output for 35 minutes. Systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), and capillary perfusion (CP) were monitored during the periods of exposure and sham exposure. Each subject underwent the same exposure/sham exposure protocol 5 times on different days. SBP, DBP, and HR were monitored with the subjects supine, while standing upright for 60 sec, and while performing the Valsalva maneuver (forcibly exhaling against a resistance). In the initial study reported in Lancet, during exposure at rest, statistically significant elevations in SBP and DBP of 5 to 10 mm Hg (p<0.0001 to p<0.01) were observed. Also in the initial study, after 30 and 60 sec of standing, exposure also elevated SBP and DBP (p<0.01). During the Valsalva maneuver, exposure lowered SBP and DBP at rest (during phase I when intrathoracic pressure is increased) and increased SBP and DBP during phases II and IIe (when any BP changes are mediated by the autonomic nervous system). Also during exposure, CP measurements indicated a statistically significant increase in vasoconstriction (p<0.01). Exposure significantly decreased mean HRs during all maneuvers. In subsequent studies reported in Radiation Research, however, the effects were reported to be the result of artifacts of the test system, and RF exposure did not appear to be responsible for changes in bp or hr. The authors initially postulated that GSM exposure to the right brain hemisphere might cause an increase in sympathetic efferent activity, which in turn increased in resting SBP and DBP most likely due to a more pronounced vasoconstriction. However, with the follow-up study in Radiation Research showing the effects were due to artifactual elements in the test procedure, these postulations were withdrawn.
Findings		No Effects
Status		Completed With Publication
Principal Investigator		Neurological University of Freiburg, FRG - braune@nzll.ukl.uni- freiburg.de
Funding Agency		Deutsche Telekom, Germany
Country		GERMANY
References		Braune, S et al. Radiat. Res., (2002) 158:352-356 Braune, S et al. Lancet, (1998) 351:1857-1858
Comments		In follow-up article in Radiation Research, the initial results were identified as artifacts of the test procedure. In addition, although the subjects were not aware of the exposure/sham exposure schedule employed, at 2 watts of output power the phone may have produced significant circuitry heating and allowed the subjects to know when the phone was on or off.