Experts: Caffeine can decrease blood flow to the brain

Experts: Caffeine can decrease blood flow to the brain

CREATED Apr 15, 2012

WASHINGTON (KTNV) - In the right amounts, caffeine can help us stay awake, focus better and lift our mood. But how does it make our brain do all that?

Caffeine is everywhere: From 320 milligrams in a Starbucks cafe grande, about the maximum you should have in a day, to energy drinks and sodas.

But could that daily dose of caffeine be changing your brain? Researchers at Wake Forest in North Carolina put it to the test.

They tested a patient by conducting two MRI brain scans. For the first scan, the patient had no caffeine in their system. Then the patient downed one coffee drink, and had a second MRI.

Dr. Paul Laurient explains the findings, "It's like a 40% drop in the blood flow to your brain. That's a lot."

Why the drop? Caffeine blocks a chemical called Adenosine, which controls blood flow to the brain. Add caffeine, and less blood circulates in the brain, more goes to your muscles, and your blood pressure and heart rate go up. So if you skip your regular coffee, that surging blood can trigger that infamous caffeine headache.

"It's like trying to get a fire hose to pump blood through your skull," says Dr. Laurient.

If you're a caffeine lover, your brain has actually changed. It now functions normally on caffeine.

The good news experts say, for healthy adults, a few cups a day isn't dangerous. But keep in mind, a little caffeine can do a lot.