Exercise is a wonder drug in so many ways – we write frequently about the cavalcade of benefits.
Yet, done to a high intensity, over many years, it is known to stress the body in certain negative ways – and the heart often bears the brunt.
A recent study from the University of Leeds, funded by leading UK heart research charity British Heart Foundation, added to this grim news: it found that older male athletes may be at higher risk of dangerous, life-threatening heart rhythms.
Published in the journal Circulation: Cardiovascular Imaging, the study found that, as people who have spent decades training, they were more likely to have heart scarring than non-athletes. To boot, athletes with scarring were 4.5 times more likely to experience an abnormal heart rhythm episode compared to those without scarring.
They studied 106 healthy male endurance athletes over the age of 50, none of whom had cardiac symptoms or a diagnosis of cardiovascular disease.
All were either cyclists or triathletes and had been exercising for 10 or more hours a week for at least 15 years, competing at all levels.
At the beginning, their hearts were scanned for scarring with MRI and they were fitted with an implantable loop recorder to measure their heart’s rhythm.
47% had heart scarring, most commonly at the bottom of their left ventricle, the heart’s main pumping chamber. This was over four times higher than a similar demographic group of non-athletes (11%).
During the two-year study period, 22% of the athletes had at least one episode of ventricular tachycardia (VT), a dangerous form of arrhythmia (irregular heartbeat), which can be deadly when it’s sustained beyond a few seconds. 78% of the 22% had previous heart scarring. Three of the participants had one or more episodes of sustained VT.
Dr Sonya Babu-Narayan, cinical director at the British Heart Foundation and consultant cardiologist, said: “There’s no doubt that exercise is good for our hearts. It helps to reduce blood pressure and cholesterol, manage our weight, and it boosts our mental health.
"But in some veteran male athletes, this early research suggests that intense exercise over many years may have affected their heart health.
“More research in veteran endurance athletes – both in men and women – will be needed to identify the small number of people who have the kind of heart scarring, together with other risk factors, that mean their life could be saved by having an implantable defibrillator.”
Too many, Cookson
One of the 106 participants in the trial was 74-year-old Brian Cookson, a Brit who led the UCI as president from 2013-2017.
Following his departure from cycling's world governing body, he began to train and compete again in bike racing, but in May 2024, while training at the Manchester velodrome, he began to feel unwell.
A new record heart rate – 238bpm – signalled all was not well and it took 15 minutes for it to return to normal, which was another red flag.
He was already aboard the Leeds study, with an implantable recorder fitted, so he got in touch and they were able to see what had happened.
“The next day, I got a call. They said, ‘Stop riding your bike, don’t do anything more strenuous than walking until we can get you in here because we think you need an ICD [implantable cardioverter defibrillator].’”
Cookson had had an episode of VT – the ventricles were contracting too quickly and weren’t able to pump blood around the body effectively. Untreated, it can cause a cardiac arrest.
By the end of the summer, he’d been fitted with the ICD, which shocks the heart if it goes into an abnormal rhythm.
Cookson is cycling again, but is no longer pushing himself like he was. “I keep a closer eye on my heart rate now and if I’m getting to 150bpm I’ll start backing off,” he says.
“I don’t think people should be put off by this – if I could go back to when I first got into cycling, I wouldn’t do anything differently. I still have all the health benefits that a lifetime of staying active brings.
“Heart problems can affect anyone so I would say to others like me, don’t take your health for granted. If you get the opportunity for a health check, take it and if you have any symptoms, rest and get them checked out.
“Everyone can benefit from exercise, and taking part in competitive sport is fun. We’ve been able to take action to manage my condition, and I’m still cycling regularly.
"The way I put it is, maybe it's time I started acting just a little bit more like I'm 70-something, rather than like I'm 20-something. One thing’s for sure – I won’t be stopping cycling any time soon!”
Leader of the study, Dr Peter Swoboda, associate professor in cardiology and consultant cardiologist at the University of Leeds, said: “In our study, the athletes who experienced dangerous heart rhythms often had symptoms first.
"I’d encourage anyone who experiences blackouts, dizziness, chest pain or breathlessness, whether during sport or at rest, to speak to their doctor and get it checked out.
“These results shouldn’t put people off regular exercise. Our study focused on a very select group, and not all the athletes involved were found to have scarring in their hearts.
“We can all benefit from being more active, and this study is an important step towards helping people take part in sport as safely as possible.”
