Study type: Medical/biological study (experimental study)

Effects of pulsed high-frequency electromagnetic fields on the neuroendocrine system med./bio.

Published in: Neuroendocrinology 1998; 67 (2): 139-144

Aim of study (acc. to author)

To investigate the influence of pulsed high-frequency electromagnetic fields in the lower microwave frequency range generated by a digital mobile telephone on the neuroendocrine system (hormone secretion) in healthy humans.



Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 8 h

Exposure 1

Main characteristics
Frequency 900 MHz
  • circular
Exposure duration continuous for 8 h
Modulation type pulsed
Pulse width 577 µs
Repetition frequency 217 Hz
Exposure setup
Exposure source
Distance between exposed object and exposure source 40 cm
Chamber The subjects slept in a specially constructed metal-free bed that was enclosed in a metal-free chamber lined with RF-absorbing material.
Setup The antenna was positioned beneath the head of the bed at a distance of 40 cm to the vertex of the subject and was operated from the neighbouring room via an extension lead.
Sham exposure A sham exposure was conducted.
Additional info After an adaptation night, polysomnographies were performed during two successive nights. The subjects were exposed in one night and sham-exposed in the other night (randomized and blinded).
Measurand Value Type Method Mass Remarks
power density 0.02 mW/cm² mean - - at 40 cm

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The only significant effect found was an interaction between field exposure and time for cortisol concentration. This indicates an alterated temporal secretion pattern of cortisol under exposure. A transient elevation in the cortisol serum level immediately after onset of field exposure was found which persisted for 1h. For growth hormone, luteinizing hormone, and melatonin, no significant effects were found under radiation compared to the placebo condition, regarding both total hormone production during the night and dynamic characteristics of the secretion pattern. The evaluation of the sleep EEG data revealed no significant effects under radiation compared to the placebo condition. However, an indication of an REM sleep suppressive effect could be found. The data indicate that weak high-frequency electromagnetic fields have no effects on nocturnal hormone secretion except for a slight elevation in cortisol production which is transient (pointing to an adaption of the organism to the stimulus).

Study character:

Study funded by

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