CHICAGO - Emergency room visits for school-age athletes with concussions has skyrocketed in recent years, suggesting the intensity of kids' sports has increased along with awareness of head injuries.

The findings in a study of national data don't necessarily mean that concussions are on the rise. However, many children aren't taken for medical treatment, so the numbers are likely only a snapshot of a much bigger problem, doctors say.

"It definitely is a disturbing trend," said lead author Dr. Lisa Bakhos, an ER physician in Neptune, N.J.

The study examined concussions in organized youth sports involving ages 8 to 19. ER visits for 14- to 19-year-olds more than tripled, from about 7,000 in 1997 to nearly 22,000 in 2007. Among ages 8 to 13, visits doubled, from 3,800 to almost 8,000.

While awareness has increased, many parents, coaches and players still don't understand how serious concussions can be, Bakhos said. Many often seem less concerned with the injury than with how soon kids can return to sports.

"They want to know if they can play tomorrow, and you're just like, 'No!'" she said. "It's not just as simple as get up, shake it off and you'll be fine.

"If they're not treated properly, with rest, then they can have long-term problems," Bakhos said. Those include learning difficulties, memory problems and chronic headaches.

The study appears in Pediatrics, published online Monday, along with a report about sports-related concussions from the American Academy of Pediatrics' sports medicine council.

A concussion means the brain has been jostled. Symptoms aren't always obvious. There usually is no loss of consciousness. And a concussion doesn't show up on an imaging scan unless there is bruising or bleeding.

Symptoms can include headache, nausea, dizziness and trouble concentrating, and may last about a week. Sometimes it can take months to recover.

Potential concussions should not be "toughed out," say the authors of the Pediatrics report. Affected athletes should always be examined by a doctor or someone else with medical expertise.

Treatment is mainly rest - both physically and mentally, avoiding activities that require concentration and focus. That may mean reducing schoolwork or staying home. Video games, computer use and TV can worsen symptoms and should be avoided, the academy report says. Some doctors advise against aspirin and similar painkillers right after a head injury because they might raise the risk for brain bleeding.

Above all, anyone with a concussion should not return to sports or other physical exertion until their symptoms have disappeared.

"If you go back in too early, that can be devastating," said Dr. Kevin Walter, co-author of the report and a concussions specialist at Children's Hospital of Wisconsin in Milwaukee. Resuming sports too soon risks another concussion that could be deadly or cause permanent brain damage, he said.

A concussion should not be dismissed as "not a big deal," Walter said. "In my mind, how the hell can a brain injury not be big deal?" he said.

Sports-related concussions have made recent headlines because of research about brain damage, depression and memory problems including Alzheimer's disease in retired NFL players who had repeat concussions.

Researchers believe young athletes may be more vulnerable than adults to lasting damage from these head injuries because their brains are still developing. Several states have adopted or are considering tougher limits on when athletes can resume play after a concussion, as have some schools, amateur leagues and the NFL.

Dr. Michael Koester, chairman of a sports medicine committee at the National Federation of State High School Associations, said young athletes increasingly are playing and practicing year-round to stay competitive, a trend that increases chances for injury.

Evan Nolte, 16, a top high school basketball player in Atlanta, says the injuries "are more serious than people think."

Evan hit his head hard on the floor during a tournament earlier this year when he dived for a ball and another player landed on top of him. He didn't think he had a concussion, and only sat out several minutes before returning to the game.

A few days later, he was elbowed in the head in another game. Evan sat out the rest of the game, feeling disoriented. His doctor diagnosed a concussion the next day and told him to avoid sports for a few weeks. When Evan had trouble focusing in class, and complained that his head was spinning, his parents took him to Children's Healthcare of Atlanta's concussion clinic.

The clinic is among an increasing number of centers nationwide that use computerized or written tests to measure mental function after concussions. Evan's results showed some deficits. His scores improved after several days, but it took him about a month to feel 100 percent.

Now he's back to training. At 6-feet-7, Evan plays competitively 10 months of the year and plans to play in college. Coaches from top schools have already shown interest.