Chicago: Spending 50 minutes with a mobile phone stuck to your ear is enough to change brain cell activity, scientists at the National Institutes of Health have said. But whether that causes any harm is not clear, the scientists added on Tuesday.

“What we showed is glucose metabolism [a sign of brain activity] increases in the brain in people who were exposed to a mobile in the area closet to the antenna,” said Dr Nora Volkow of the NIH, whose study was published in the Journal of the American Medical Association.

The study was meant to examine how the brain reacts to electromagnetic fields caused by wireless phone signals. Volkow said she was surprised that the weak electromagnetic radiation from mobile phones could affect brain activity, but she said the findings do not shed any light on whether they cause cancer.


“This study does not in any way indicate that,” she said. “What the study does is to show the human brain is sensitive to electromagnetic radiation from mobile phone exposures.”

There are around five billion mobile phones now in use worldwide. Studies have linked their use to an increased risk of brain cancers, but a large investigation by the World Health Organisation was inconclusive. Volkow’s team studied 47 people who had brain scans while a mobile was turned on for 50 minutes and another while it was off.

While there was no overall change in brain metabolism, they found a seven per cent increase in the region closest to the mobile when the phone was on.

Volkow has called for more study in the area. Meanwhile, she has switched to using an earpiece.