For years there have been concerns over the potential effects of long-term cell phone use on the brain, and studies examining brain cancer rates have been contradictory. With over 200 million Americans owning a cell phone (roughly 70% of the country’s population), the debate continues.

According to a new study published in the Journal of the American Medical Association, holding a cell phone up against your ear changes the activity in your brain – however, the health implications are not clear. In the year-long study, researchers from the NIH placed cell phones receiving 50-minute muted calls near the ears of 47 men and women. They found that electromagnetic fields emitted by cell phones appear to affect the brain’s glucose metabolism, which is considered a marker for brain activity; glucose metabolism increased by 7% in the orbitofrontal cortex and temporal pole, the area of the brain near the cell phone’s antenna.

For latest news and updates

The increase, however, was modest. By comparison, the metabolism of the visual cortex may spike by as much as 50% when people look at a pattern on a computer screen.

Although the study raises a lot of questions, it offers few answers.  While increases in brain glucose metabolism happen during normal brain function, many question whether repeated artificial stimulation as a result of exposure to electromagnetic radiation might have a detrimental effect.  The hope is that these new data will broaden the focus of cell phone research and health.