Elite athletes' heart function

A/Prof La Gerche says: “We have long known that elite athletes have very different hearts to the general population. Exercise promotes profound heart changes. The heart is large in all elite athletes but there is still considerable variation ranging from large to enormous. The long-term significance of the most extreme changes is not yet certain.

“We discovered that one in six athletes had reduced heart pumping action, as well as showing for the first time the role genetics plays in heart function in these athletes. It’s vital that we monitor these athletes over the coming years to see the long-term impact on their health, which is still to be played out.

“We want to keep our athletes healthy and prevent them from suffering a sudden cardiac arrest. The better we understand the athlete's heart, the more we will be able to identify risks in advance of tragedy.”

The team of international researchers has now recruited more than 400 elite endurance athletes, that includes winners of the world's biggest cycling races. The analysis on the first 281 athletic men and women was performed using the same state-of-the-art exercise and heart imaging in six cities across Australia and Belgium. It involved undertaking genetic testing, as well as analysing their heart function and structure in specially designed heart exercise laboratories. The results were published in Circulation.

Key findings

• One in six athletes or 15.7% had heart measures that fall in a range normally associated with heart disease – including an enlarged heart, irregular rapid heartbeat and changes in the heart’s left ventricular chamber that is responsible for pumping blood full of oxygen out to the body.

• The reduced heart function was only observed when they were at rest. When exercising, the heart functioned at levels known as super normal, which means their hearts were able to substantially increase the pumping action when needed to boost cardiac output.

• Athletes were also genetically screened to discover if they had genes associated with developing dilated cardiomyopathy (DCM). Those elite athletes with the highest genetic load were 11 times more likely to have a reduction in heart function measures.

Professor Diane Fatkin, of the Victor Chang Cardiac Research Institute, who undertook the genetic analysis of the athletes alongside Associate Professor Eleni Giannoulatou, says this study was the first in the world to look at the role of genetics in susceptibility to DCM in athletes.

“The phenomenon of the athletes’ heart has long been known, but we were the first team to investigate the role an athlete's genetic makeup plays in their heart function and structure. What we have found is that there are far more profound changes than thought, and that a high number of these athletes do have altered heart function,” says Professor Fatkin.

“It’s very important we don’t think of these athletes as having sick hearts because they can still function at a very high level. But we don’t know what the long-term effect will be and if this means these athletes will go on to develop cardiomyopathy.”

A/Prof La Gerche says it is now vitally important to follow this same group of athletes over the next 25 years to see if they do go on to develop DCM.

“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,” says A/Prof La Gerche.

“Our overall hope from this research is that we can make all sport safe for all participants. Understanding the interplay between genetic traits and high-dose exercise is a step towards this goal”.