Danker-Hopfe H, Dorn H, Bahr A, Anderer P, Sauter C. Effects of electromagnetic fields emitted by mobile phones (GSM 900 and WCDMA/UMTS) on the macrostructure of sleep. J Sleep Res. Ahead of print. Jun 16, 2010.
All studies on the effects of the EMFs emitted by mobile phones on sleep have been conducted with Global System for Mobile Communications (GSM) signals. There are no studies on the effects on sleep of Wideband Code-Division Multiple Access (WCDMA)/Universal Mobile Telecommunications System (UMTS).
The objective was to study possible effects of both types of signals on sleep.
This double-blind randomized cross-over study included male volunteers aged 18-30 years. The subjects were healthy, did not take any drugs, were non-smokers and did not have sleep disorders as determined from a questionnaire, detailed medical interview and medical examination including EEG, ECG and blood tests. Prior to the experiments, the subjects were screened for sleep-related breathing disorders and sleep quality by ambulatory devices. The subjects slept 10 nights separated by a 2-week interval in the laboratory. The first was an adaptation and screening night. During the following 9 nights, GSM 900, WCDMA/UMTS 2000 MHz and sham exposure were applied for 3 nights each in a randomized order. The exposure system was set to reach but not exceed the ICNIRP specific absorption rate (SAR) limit for the general public (2 W/kg averaged over 10 g). The exposure continued for 8 hours from 23:00 to 7:00. Electroencephalogram (EEG), mental and submental chin electromyogram (EMG), horizontal and vertical electro-occulogram (EOG), ECG and EMG of both legs, and thoracic breathing excursions were recorded.
Significant differences between GSM 900 and sham exposure conditions were observed for distribution of 13 of the 177 investigated variables (7.3%). Of these variables, six were related to rapid eye movement (REM) sleep. Under WCDMA exposure, deviating distributions compared to sham exposure were observed only for 3 variables (1.7%).
The six REM sleep-related variables for which significant differences between GSM 900 and sham exposure were found are not independent. They are different from the variables found to be affected in other studies. The effect on REM sleep duration observed in this study (an increase) was the opposite of reported in another study. Two of the variables found to be affected in this study have no physiological meaning. For these reasons, the authors assume that the observed differences may be due to chance. The number of significant differences for WCDMA exposure is small, and these differences cannot explain a subjectively perceived sleep disturbing effect from this kind of signal reported by some people. The alterations detected in this study do not resemble those observed in patients who suffer from insomnia.
The authors have concluded that their study provides no evidence for a sleep-disturbing effect of GSM 900 and WCDMA exposures.