Cardiac autonomic activity during sleep under the influence of radiofrequency electromagnetic fields

Question of the study: We investigated the influence of radiofrequency electromagnetic fields emitted by digital mobile telephones on heart rate variability (HRV) during sleep in healthy young men. Subjects and methods: For each subject, two polysomnographies were carried out in the sleep laboratory under field and sham exposure, respectively. Field intensity was weak so that thermal effects could be excluded. HRV was assessed from the electrocardiogram both in the time and in the frequency domain. Results: For most HRV parameters, significant differences between sleep stages were found. 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- and high-frequency components of HRV, 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 HRV parameters, no significant differences were found between field and sham exposure. Conclusions: Under the given experimental conditions, no influence of weak radiofrequency electromagnetic fields on cardiac autonomic activity could be proven. © 2005 Blackwell Verlag, Berlin.