Elite cyclists are renowned for having efficient hearts and cardiovascular systems, boasting low resting heart rates and the ability to work at a high percentage of their maximum.

The likes of Miguel Indurain reportedly had a resting heart rate of 28 beats per minutes, significantly lower than the average adult’s 60-100.

Despite all these positives, for an unknown reason many elite endurance athletes, especially as they get older, are more likely to have heart rhythm disturbance, known as arrhythmia. It was thought this disturbance was caused by the autonomic nervous system going into overdrive and lowering resting heart rate.

However, new research conducted by the University of Manchester no longer supports this theory. By studying how mice respond to endurance exercise researchers saw a reduction in the important pacemaker protein, HCN4. This protein reduction is thought to cause the heart’s natural, built-in pacemaker to respond, by changing the heart’s rhythm for a sustained period.

Although this research highlights the possible harmful effects of prolonged endurance training on the heart, the researchers stress that the benefits of regular endurance exercise still largely outweigh the risk.

Study leader, Professor Mark Boyett, explained: “This is important because although normally a low resting heart rate of an athlete does not cause problems, elderly athletes with a lifelong training history are more likely to need an artificial electronic pacemaker fitted.”

With professional cyclo-cross rider Niels Albert recently announcing his retirement from racing due to cardiac problems, aged 28, it’s something to be aware of. If you are experiencing odd heartbeats or palpitations make sure you visit your doctor. Don’t assume you should be fine even if you have been cycling for many years.