Athlete Christina Ruiz managed to outrun death.

On Dec. 2, the 22-year-old student at Cal State Long Beach was in the midst of a run for a kinesiology class final when she suddenly collapsed.

She had a quick seizure and, afterward, her instructor couldn't find a pulse. The teacher administered CPR and CSULB police later jump-started her heart with a defibrillator.

Now, three weeks out of the hospital, Ruiz sees her survival as a miracle and thanks her rescuers.

"I just thought of them as my heroes and my angels," Ruiz says. "And I just felt so incredibly lucky.'

Lucky to be alive. But Ruiz, a workout fanatic, faces possible misfortune. Doctors say that she has a weak heart muscle that might impair her pursuit of a fitness career.

The kinesiology major, who had a pacemaker-and-defibrillator device implanted after her seizure, has spent recent weeks at home under constant supervision, without any exercise.

"I'm going through so many emotional ups and downs everyday ...' she says. "I'm starting to feel better physically but the emotions are taking over and that's hard.

"Because that was like my life, was to be physically active and to inspire and help other people be physically active and healthy,' she adds.

This isn't the first time Ruiz has faced health obstacles. As a child, she fell off a jungle gym and shattered her femur. Doctors didn't expect her to walk again.

And this latest heart episode isn't Ruiz's first. In middle school, she turned around at her desk to pass a paper and her left arm went numb. Doctors learned that a major valve in her heart wasn't working properly.

Even with those two setbacks, though, Ruiz went on to become a fitness fanatic, using competitive athletics to break from a shy personality.

She originally had intended to study biology in college. But when she started working with a 24 Hour Fitness gym trainer, she realized that was the career for her.

"I've always loved the gym, and I've always loved health and fitness,' she says. "And I said, 'God, I might was well major in it."

Ruiz says her dream is to teach people to look beyond their limitations.

"And I was so adamant about that then, and now that this has happened to me, it's an extremely life-changing experience,' she says. "And I hope to be active again and to really inspire people.'

She hopes doctors will soon tell her she can resume modest exercise. Because Ruiz is so physically fit, she has progressed more quickly than her doctors first guessed. She hopes to go back to school so she can graduate on schedule, in the spring of 2006.