Study type: Medical/biological study (experimental study)

Cardiac Autonomic Activity during Sleep under the Influence of Radiofrequency Electromagnetic Fields. med./bio.

Published in: Somnologie (Somnology) 2005; 9 (4): 180-184

Aim of study (acc. to author)

To study the influence of radiofrequency electromagnetic fields emitted by digital mobile telephones on heart rate variability during sleep in healthy young men.

Background/further details

Field intensity was weak so that thermal effects could be excluded.
The relation between low frequency and high frequency components of heart rate variability represents the balance between the two branches of the autonomic nervous system. The high frequency component reflecting sinus arrhythmia, has been attributed to the modulation of the parasympathetic output. The low frequency component has been referred to both sympathetic and parasympathetic activity.

Endpoint

Exposure

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

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 8 h
Modulation
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 Soundproof and electrically shielded sleep laboratory
Setup The mobile phone was positioned at the head of the bed at a distance of 40 cm to the vertex of the subject with the antenna axis perpendicular to the axis of the subject's body.
Sham exposure A sham exposure was conducted.
Additional info Following an adaptation night, two polysomnographies were carried out for each subject over 8 h from 23:00 h to 7:00 h with or without exposure to the EMF in randomized and single-blind order. Field intensity was weak so that thermal effects could be excluded.
Parameters
Measurand Value Type Method Mass Remarks
power 8 W peak value - - -
power density 0.05 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)

Under these experimental conditions, no influence of weak radiofrequency electromagnetic fields on cardiac autonomic activity could be proven.
For most parameters of heart rate variability, significant differences between sleep stages were revealed. Particularly, on the basis of spectral analysis of the RR intervals, slow wave sleep was characterized by a low LF/HF ratio of the low frequency and high frequency components of heart rate variability, indicating a predominance of the parasympathetic over the sympathetic activity in autonomic cardiac control. During REM sleep, the balance was shifted in favour of the sympathetic tone. For all heart rate parameters, no significant differences were revealed between electromagnetic field exposure and sham exposure.

Study character:

Study funded by

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