The death of a high school athlete in Lincoln this week was stunning news. While the cause of that death is still under investigation doctors say some underlying conditions can be difficult to foresee.

High school athletes push themselves.

Burke High sophomore Caitlin Bennett says, "It's basically all about winning. You always want to win."

But that spirit makes some parents nervous, especially in light of the recent death of a football player at Pius X.

Marilyn Pribyl is a mother who says, "It's a little bit scary. You just wonder are they training too hard? Are they eating right? Is there something like that that we as parents are missing."

Dr. Mark Franco says, "There are some causes of sudden death in the athletes that are unpredictable and impossible to determine ahead of time."

Dr. Franco says any number of issues can cause an athlete to collapse -- like genetic diseases, hypothermia from overheating, or heart problems.

He says, "There are cardiac diseases where the heart doesn't beat correctly, and sometimes that will occur in a very good, Olympic-caliber athlete."

Most schools have defibrillators to get the heart going again but it's not necessarily the first thing athletic trainers go for.

Trainer Scott Martens says, "I'll go out and I'll check that athlete first. A lot of times, they're just lying there, rolling around. It's not the first thing you think of when you think of an athlete being down on the field is a heart problem."

Sudden athlete deaths are extremely rare, striking one in 200,000 athletes a year. It might come without warning but Dr. Franco says, there are precautions athletes can take.

"Make sure that they're well hydrated, make sure that they replace their electrolytes," he said.

And discuss chronic health issues like asthma, as well as medications, with your doctor before participating in sports.

Caitlin Bennett says, "If you have to train, you kind of have to know when to stop and when to say, 'I can't do this right now.'"

Many businesses and most schools have automated external defibrillators, or AEDs, for cardiac emergencies.

While we don't yet know what caused the death of John Liescheski at Pius, heart problems are the leading cause of sudden athlete death.