Do genes that code athletic heart enlargement carry a risk of heart problems?

World-first research has for the first time shown athletes may have a genetic predisposition that can lead to reduced heart function.

Australian cyclist Will Walker was forced to retire in 2014 after developing a dangerous heart condition. Picture: NCA NewsWire/ David Crosling

The genes that make someone a superstar could also be their Achilles heel according to the lead author of a landmark study that shows for the first time the role genetics play in the differences in elite athlete hearts and the general population.

“We have long known that elite athletes have very different hearts to the general population,” Andre La Gerche said. “Exercise promotes profound heart changes.

“Regular exercise is associated with clear health benefits, but maybe there is a small group with a genetic predisposition in whom that benefit is less.

“It might even be potentially dangerous for them to exercise at this incredibly high level.”

William Walker was a professional endurance cyclist “in a previous life” when, at age 28, a gradual onset of cardiac issues ultimately forced him to retire after nearly dying during a race.

“It actually took a year of investigations to figure out what I had,” Dr Walker, now 38, said.

“At that time it was not well described, not many people had those types of issues.”

Dr Walker was an early participant in the study, which showed he had a genetic predisposition to reduced heart function. Associate Professor La Gerche and researchers from Belgium studied Dr Walker and nearly 300 other elite athletes at the St Vincent’s Institute in Melbourne and the Victor Chang Cardiac Research Institute.

Walker competing in 2008.

“We discovered that one in six athletes had measures of function that would be considered abnormal,” Prof La Gerche said. “The takeaway finding was that the hearts on average were much larger than had ever been described in athletes before. The bigger the heart, the more blood you can pump around.

“If you have the genes that code for enlargement, then if you add sport to that you can get a super big heart. That is at least initially a performance enhancer, and in other settings those same genes can cause heart muscle enlargement, weakness and problems with heart failure.

“We see less heart failure in athletes, but what we do see is heart rhythm problems.”