A new study by researchers in the US and Sweden suggests that using a mobile phone could interfere with your quality of sleep.
The study is published in PIERS Online, a peer-reviewed online journal that publishes new articles on all aspects of electromagnetic theory and applications. PIERS stands for Progress in Electromagnetics Research Symposium (PIERS).
The study was the work of researchers from the Wayne State University in the US and the Karolinska Institutet, in Sweden, and other colleagues.
The researchers studied 36 women and 35 men, of whom 22 of the women and 16 of the men had reported symptoms they attributed specifically to mobile phone use (SG or symptomatic group), and the rest reported no such symptoms (NG or non symptomatic group).
The participants came from a pool of volunteers recruited specifically for the study and were screened by doctors to rule out conditions that could have interfered with the findings.
They then had three sessions in the laboratory the first being a habituation session, followed by two experimental sessions.
During the two experimental sessions the participants were either exposed to the equivalent of mobile phone signals or to sham ones for three hours, without them knowing which was which. The researchers collected data before, during, and after each session. This included self-reported symptoms of headache, mood, cognitive function, and electroencephalographic recordings.
The mobile signals were on a 884 MHz GSM wireless communications band and were directed to the left hemisphere of the brain, giving an average exposure of 1.4 Watts/kg including periods of DTX and Non-DTX (the latter being when the signal is on all the time, even when no communication is taking place).
The results showed that participants took longer to reach stage 3 deep sleep and had shorter stage 4 deep sleep after actual exposure to mobile signals compared to when they had the sham exposure. These stages of sleep are believed to be important for helping to recover from daily wear and tear.
The participants who had not been reporting symptoms from mobile phone use reported more headaches during real exposure than in sham exposure, but neither the SG nor the NG group were able to tell whether they had received real or sham exposure more reliably than by chance.
The research is still to be completed with further analysis of self reported and measured results and health implications to be explored.
The Mobile Manufacturers Forum who funded the study has issued a “viewpoint” on the study, pointing out that it should be seen in “light of the total research effort into mobile phone safety”.
They point to the weight of research reviewed by the World Health Organization (WHO), which led them to conclude that none of them say exposure to radio frequency fields from mobile phones causes harm.
In their communication the MMF remind readers that “the claims are made in a conference abstract that has yet to be published in a scientific journal”, and that the abstract is being promoted by a public relations agency on behalf of a company that “sells replacement batteries that claim to emit ‘protective’ RF [radiofrequency] fields”.
The MMF mentions another study that did not find any disturbance to deep sleep patterns resulting from mobile phone use.
However, not everyone agrees with this viewpoint. A representative of Powerwatch, a group that researches the effect of electromagnetic fields on health told the BBC that the evidence against mobile phones is getting stronger and people should take precautions like not making mobile calls in the evening (use a landline) and not sleeping with the mobile phone on the bedside table.
“The Effects of 884 MHz GSM Wireless Communication Signals on Self-reported Symptom and Sleep (EEG)- An Experimental Provocation Study.”
PIERS Online Vol. 3 No. 7 2007 pp: 1148-1150.
Bengt B. Arnetz, Torbjorn Akerstedt, Lena Hillert, Arne Lowden, Niels Kuster, and Clairy Wiholm.
Sources: journal article and abstract, MMF viewpoint, BBC News.
Written by: Catharine Paddock