Study type: Medical/biological study (experimental study)

Effects of short- and long-term pulsed radiofrequency electromagnetic fields on night sleep and cognitive functions in healthy subjects. med./bio.

Published in: Bioelectromagnetics 2007; 28 (4): 316-325

Aim of study (acc. to author)

To study whether the electromagnetic field emitted by mobile phones affects sleep measures or learning and memory consolidation in healthy subjects after one and six consecutive days of exposure.

Background/further details

20 healthy young male participants were included (10 for sham exposure) and nocturnal sleep was recorded during eight consecutive nights. In the second, third, and last night, polysomnographic night sleep and cognitive functions were investigated. After the adaptation and baseline nights (first and second night), the subjects were exposed to a radiofrequency electromagnetic field during the following six nights.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: repeated daily exposure, 7 to 9 h, for 6 nights
  • power: 28.5 W peak value
  • SAR: 1 W/kg maximum
  • SAR: 875 mW/kg average over mass (1 g)
  • SAR: 24 mW/kg average over mass (whole body)

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration repeated daily exposure, 7 to 9 h, for 6 nights
Modulation
Modulation type pulsed
Additional info

modulation according to a typical GSM signal including 2 Hz, 8 Hz, 217 Hz, and 1733 Hz components

Exposure setup
Exposure source
Distance between exposed object and exposure source 30 cm
Chamber A closed anechoic chamber made of foam absorbers mounted on a wooden framework was built around the bed which was free of metal. All instruments were located outside.
Setup The EMF was produced by an array of three λ/2-dipole antennas oriented vertically and placed 30 cm apart on a horizontal axis perpendicular to the body axis and 30 cm away from the top of the head. The antenna spacing was optimized for an almost uniform field distribution in the area where the head was placed during sleep.
Sham exposure A sham exposure was conducted.
Additional info The control group followed the study design with a sham exposure.
Parameters
Measurand Value Type Method Mass Remarks
power 28.5 W peak value - - -
SAR 1 W/kg maximum estimated - -
SAR 875 mW/kg average over mass estimated 1 g -
SAR 24 mW/kg average over mass estimated whole body -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • before exposure
  • during exposure

Main outcome of study (acc. to author)

The data showed no significant effects on night sleep parameters or on cognitive functions. The authors were unable to reveal either short-term (after one night exposure) or cumulative long-term effects (after six night exposure) of radiofrequency electromagnetic fields on night sleep and cognitive functions.

Study character:

Study funded by

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