A Journal of the American Medical Association report found 50 minutes of continuous cell phone use is enough to register "cellular" changes in the brain.
Scientists used positron emission tomography to measure how cells take up glucose.
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.
"Now that's a very surprising finding because it's really the first time that we actually have shown that microwave energy, when focused into the brain, will increase the activity within that area of the brain," said Dr. Keith Black, the head of neurosurgery at Cedars-Sinai Medical Center.
Black says the future health effects are unknown, but other studies have suggested extended cell phone use can affect memory.
"Will the cell phone use accelerate that memory decline? Will it accelerate our cognitive decline and our ability to manipulate language function?" said Black. "So all of those questions are really raised by this study."
So what should you do with your cell phone? Black says it's better to be safe than sorry, and folks should do as much as they can to keep their cell phones away from their heads as much as possible.
"Practice using cell phones in a safe fashion by using either the speaker or hands-free," said Black.
Black says corded earphones are your best bet. Yet many cell phone users say they'll take their chances.
"I'm just not going to stop. There's bigger things to worry about than the cell phone," said Alexandra Flahive.