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.
|Exposure duration||continuous for 8 h|
|Pulse width||577 µs|
|Repetition frequency||217 Hz|
|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.|
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.