Influence of low power cm-/mm-microwaves on cardiovascular function

Abstract

The present study has been designed to investigate physiological effects of short (15 min) exposure to low level energy microwaves (< 10 microW cm(-2)). To this end heart rate, PQ, QS and ST (electrocardiography), respiration (conductive stretch band around the thorax), skin temperature (thermocouple), skin conductance (Ag/AgCl electrodes), systolic and diastolic blood pressure (automatic cuff) were continuously recorded in a group of 50 test persons before, during and after a 15 min exposure to 3 microW cm(-2) high frequency (77 GHz) microwaves. After an equilibration period of 30 min the first group of test persons and after additional 30 min the second group of test persons were exposed. The study has been performed in a strict double blind design. While significant effects on the measured parameters were observed depending on time ('calming' effect), no significant difference was observed between exposure and sham exposure to microwaves. In view of the small scatter of the data the present study rules out physiologically relevant effects of low level energy on the autonomic nervous system and cardiovascular function.

Insensitivity of cardiovascular function to low power cm-/mm-microwaves

“…In a previous study, we have been unable to detect any influence of exposure to 3 mW/cm 2 of 77 GHz emitted by a commercially available automobile radar system for adaptive cruise control (ACC) on cardiovascular function (Mü ller et al 2004). Those observations do, however, not rule out any effects of exposure to microwaves of higher energy and lower or higher frequencies.…”

“…The study design was identical to the previous study (Mü ller et al 2004). Following an equilibration period of 30 min the experimental period consisted of a first 15 min exposure interval, a 15 min recovery phase, a second 15 min exposure interval and a second recovery phase (see Figure 1A).…”

“…To this end, (i) the mean values of the data within the exposure and the sham interval were taken, (ii) for each individual and each variable the differences of the mean values (exposure versus sham exposure) was considered thus excluding the influence of different baselines of test persons, (iii) for these variables a linear statistical model was used assuming linear superposition of effects and a multivariate normal distribution for the error terms. Taking into account the results of the previous study (Mü ller et al 2004), exposure effects and calming effect (the persons calm down in the time course of the experiment) as well as ambient temperature (difference of the ambient temperature between the first and the second possible exposure time) have been used as factors to explain the data. The fact that the exposure effects were expected to appear simultaneously in all variables was taken into account by choosing a multivariate test, i.e., performing a MANOVA Pruscha (1996).…”

“…The experiments were performed under strictly double-blind conditions, i.e., neither the test person nor the experimenters performing the measurements and evaluating the data knew the respective interval (first or second) of the microwave exposure. The design of the experiment and the statistical model (Mü ller et al 2004) was planned to reduce the noise of the data. To this end, (i) the mean values of the data within the exposure and the sham interval were taken, (ii) for each individual and each variable the differences of the mean values (exposure versus sham exposure) was considered thus excluding the influence of different baselines of test persons, (iii) for these variables a linear statistical model was used assuming linear superposition of effects and a multivariate normal distribution for the error terms.…”

“…Kantz et al humidity between 29% and 35%. To stabilize the mental state of the test participants (Mü ller et al 2004), the experiments were performed under continuous exposure to the 'welltempered piano' of J. S. Bach. The microwave signal was composed of six frequencies in the range between 5.8 and 110 GHz.…”