You don't have to be hit that hard for your brain to feel the impact. Now, a new concussion test could tell a coach when a player needs to sit out.
College senior Zach Barley has taken some hard hits over the years.
Number 29 was once pulled from a game after suffering a concussion, but you don't have to be hit that hard to damage your brain-there's now something called a sub-concussive hit.
Cleveland Clinic and the University of Rochester developed a blood test taken before, during, and after a game to find out if those hits can damage the blood brain barrier, which is the lining in each of the blood vessels in your brain that prevents harmful molecules from getting in. When a player is hit hard, that barrier is breached.
Dr. Damir Janigro, Director of Cerebrovascular Research at Cleveland Clinic's Lerner Research Institute said, "The blood test is based on a molecule called S100B, which is present primarily in the brain and is normally not present in the blood. When the barrier breaches, these molecules show up in the blood." And the immune system attacks it.
Dr. Janigro explained "The body believes there is a pathogen, or bacteria, or a fungus, or some enemy to fight." Then it goes into the brain and can attack brain tissue, similar to what happens with Alzheimer's patients.
Right now, Zach's brain's intact. "But," he said, "I'm not willing to risk my life over playing a game."
This test could mean he and other players won't have to.