The headaches and fatigue that some people report after exposure to electronics ranging from cellphones to microwaves may be the result of a so-called "nocebo" effect, a new report suggests, because they believe that such exposure may be harmful to human health.

The report, released earlier this week by the European Commission's Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR), examines how electromagnetic fields may impact human health.

Electromagnetic fields range in frequency from high radio frequencies, which are generated by devices such as cellphones, to intermediate frequencies, such as those generated by computer screens, to extremely low frequencies, such as those from power lines.

According to the report, there is some evidence to suggest that exposure to radio frequency influences brain activity or sleep patterns.

However, it is not clear how this may happen and previous research has not proven any adverse health effects as a result.

"Some people attribute headaches, fatigue and dizziness to radio frequency (RF) fields," the report points out.

"Such complaints have raised concern that certain individuals may be more sensitive than others to electromagnetic fields. Present knowledge suggests that these symptoms are not linked to exposure to radio frequency fields, but to a 'nocebo' effect, an effect caused by the expectation or belief that something is harmful."

In another note of reassurance to cellphone users, the report concludes that research has yet to find a conclusive link between cellphone use and head cancers, despite public fears over the long-term health ramifications of using mobile phones.

However, most of that research is based on 10 years of use or less, so the report recommends study on the potential health effects of using a mobile phone for longer than a decade.

The report also recommends further study on the health effects of cellphones on children, who face greater exposure to radio frequency compared to adults because of the age at which they begin using them.

"Few studies have addressed the possible effects of mobile phones on children, despite concern that children could be more vulnerable than adults because their nervous systems are still developing, their brain tissue is more conductive, and their heads might absorb more energy from mobile phones," the report warns.

As for intermediate frequencies, which are generated by a range of sources from anti-theft devices to radio transmitters, the report found little data on exposure to these frequencies and how it may impact human health.

Because "a growing number of workers are exposed to intermediate frequency fields, it is important that research on possible health effects is given a priority," the report says.

And human exposure to extremely low frequencies (ELF), which are generated by power lines and home appliances, as well as trains and subway systems, is often well below safety limits, according to the report.

Previous research has found that children who were exposed to relatively strong ELF magnetic fields from power lines were more likely to develop leukemia than children exposed to weaker fields.

But the report cautions that the findings were based on statistical data and animal studies have not proven how ELF fields might cause the disease.

On a troubling note, the report cited new research that suggests a possible increase in Alzheimer's disease cases with exposure to extremely low frequency fields.

But as with childhood leukemia, these findings have not been duplicated in experiments on animals and it is unclear how exposure may lead to the development of the disease.

While the report does not ring serious alarm bells or make urgent recommendations about current exposure levels, it does recommend further research to address the potential health ramifications, including:

  • the potential cancer risks in a large population over the long term
  • leukemia and other disease risks in children
  • risks to health workers from medical equipment
  • damage to genetic material and effects on the nervous system