NEW YORK - THE day after Ryan Shay died during the US Olympic marathon trials on Saturday, his family had no more answers.

The seemingly healthy 28-year-old was stricken early in a race he had run many times.

An autopsy was inconclusive and the coroner wants to take a closer look at his heart.

For now, his relatives are left to wrestle with the question of whether Shay should have become a marathon runner after he was found to have an enlarged heart when he was 14. Experts say the issue is complicated.

According to Dr Paul Thompson, a cardiologist who specialises in heart disease in athletes, most elite athletes have hearts that are enlarged by their exercise regimen.

He said the key was to look not just at the size, but whether the walls of the heart were thicker than normal, forcing the heart to work harder to pump blood.

That could signal a potentially dangerous condition called hypertrophic cardiomyopathy, which is responsible for a quarter of sudden deaths in American athletes.

One in 500 people have the disorder; some people have no symptoms.

'Sometimes it can be difficult to distinguish between these two conditions - one being benign and one being potentially lethal,' said heart specialist Dr Lori Mosca.

She spoke at an American Heart Association meeting, where cardiologists have been talking about Shay's death.

'We have to use this as an example to try to prevent future problems,' said Mosca, a marathoner herself. 'More and better screening of athletes is needed.'

Dr Barry J. Maron, of the Minneapolis Heart Institute Foundation, writes guidelines that help doctors screen athletes for sudden death.

The process includes questions that focus on spotting potential heart problems through a personal and family medical history and a physical exam.

'But it's not perfect. Athletes with certain abnormalities can slip through that process,' he said.

While the inherited condition of hypertrophic cardiomyopathy is mostly found in the young, other heart problems can cause sudden death in those over 35.

Mosca said sedentary men over 40 and women over 50 should be screened before starting a vigorous exercise programme.

'Even with an evaluation, there's no guarantee that you can prevent sudden death,' she said. 'What ultimately happens is a balancing of the risk of participating in sports against the benefits. That's true for everyone.'

Shay had taken his medical tests last spring and was cleared for running, according to his father, Joe Shay.

He said his son had not complained of any problems.

Thompson said: 'I might not have thought he was at risk either, because he's had it since he was 14. These things don't always cause problems.'

Shay's long-time coach, Joe Vigil, said that his runners went through extensive performance tests twice a year, measuring things like oxygen usage and heart rate during intense exercise.

He added that Shay always had excellent results.

He also said Shay never expressed any worries about his heart or potential dangers, even though he had adrenal fatigue syndrome in 2004.

According to George M. Dallam, a professor of exercise physiology and once a triathlon coach, that is a common condition among endurance athletes.

'That probably affects virtually every elite marathoner at some point in his career,' Dallam said. 'That's not uncommon, and that's also not a cause of anything that happened in this race.'

Driving himself to exhaustion was fairly common for Shay, who was often spotted running near his home at Lake Michigan even during the winter. He died doing something he loved.

He collapsed about eight kilometres into the race in New York's Central Park.

ASSOCIATED PRESS

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