Emily Johnston is a soccer goalie. Two concussions have side-lined the 16-year-old in the past two years.
"I really didn't know I had a concussion, I just knew I had a lot of pain. I didn't tell my coach because I wanted to play."
Now new guidelines from the American Academy of Neurology say any athlete showing signs of a concussion should be immediately taken out of a game and not return until a doctor gives the ok.
"Short term it's prolonged headaches, nausea, difficulty in school, long term we're seeing much more significant issues, memory issues," says Dr. Tracy Zaslow.
Teen and younger athletes should be managed even more conservatively because their brains are still developing.
More than one million athletes suffer concussions each year, and according to the CDC, kids and teens get them more often and take longer to recover.
The guidelines emphasize a gradual return to play.
"Having them home and not having a lot of stimuli which includes computers, loud music, TV, and even intense studying."
Emily's mother hopes the new report influences younger athletes.
"You don't want a child to stop doing something they're very passionate about and love, but you also don't want them to have any sort of consequences."
Now that Emily is aware of the long term dangers, she says she'll play it safe if she takes another hit to the head.
Research shows athletes like Emily who have a history of concussions are at greater risk for having another.