Using a cell phone for 50 minutes increases brain activity in areas of the brain closest to the phone’s antenna, a new study from researchers at the National Institutes of Health has found.
This finding adds to growing concern about both the short- and long-term health effects of cell phone use.
For the study, which was published Tuesday in the Journal of the American Medical Association (JAMA), Dr. Nora Volkow, director of the National Institute on Drug Abuse, and her colleagues recruited 47 healthy volunteers who lay in a positron emission tomography (PET) scanner for 50 minutes with cell phones pressed to each ear. PET scans measure brain glucose metabolism, an indicator of brain activity.
Two PET scans were taken with each volunteer. During one scan, both cell phones were turned off. During the second scan, the phone in the left ear was deactivated, but the one in the right ear was turned on to play a recorded message. The sound was muted during the message to avoid auditory stimulation to the brain.
The study found that the volunteers’ overall glucose metabolism, or brain activity, was not affected when the phone was on or off. But there was a statistically significant 7 percent increase in activity in brain tissue near the phone’s antenna when the phone was activated.
This finding “indicates that the brain was being activated by the radio frequencies from the cell phone,” Volkow said in a JAMA video report. “… Even though the radio frequencies that are emitted from current cell phone technologies are very weak they are able to activate the human brain to have an effect.”
Clinical significance unknown
The still-unanswered question, of course, is whether that increased activity poses any health risks. As an editorial accompanying the JAMA study points out, the clinical significance of the study’s findings are unclear. “The biological significance, if any, of increased glucose metabolism from acute cell phone exposure is unknown, [but] the results warrant further investigation,” said the editorial’s authors, University of Washington (Seattle) bioengineering professor Henry Lai and Swedish cancer specialist Dr. Lennart Hardell.
Previous observational studies (which can show only an association between two things, not a direct cause-and-effect) have had mixed results, with some finding an increased risk of brain tumors among cell phone users (particularly heavy users) and others finding no such increased risk.
More research will follow
Cell phone manufacturers and others have claimed that the non-ionizing radiation emitted by cell phones is too weak to have a detrimental effect on the brain.
This new study, however, suggests that there’s a biological mechanism by which the exposure to cell phones can alter brain function — and possibly create health problems.
“The bottom line is that it adds to the concern that cell phone use could be a health hazard,” Lai told the New York Times. “Everybody is worried about brain cancer, and the jury is still out on that question. There are actually quite a lot of studies showing cell phone radiation associated with other events, like sleep disturbances. But people have not been paying a lot of attention to these other types of studies.”
People will be paying more attention now. Stay tuned. We’re going to see a flurry of new studies. And, in the meantime, you may want to take the precautions that Volkow recommended to the Times: Use a headset or earpiece when you’re on your cell phone.