Male endurance cyclists at ‘four times greater risk of atrial fibrillation than sedentary population’ – here’s what you need to know about Afib

It was the summer of 2011 and life was good. In anticipation of a late-season cycling trip to the Dolomites, I’d been steadily building fitness since January. One Saturday, bored of my local Cotswold rides, I drove down through Devon to run the spectacularly pretty but brutally hilly 24km Sidmouth to Beer coastal path. Despite the 2,000m of ascent, I remember gliding effortlessly along the cliff-tops that day with just the gulls for company, wheeling above me in a brilliant blue sky. Back in Sidmouth, lounging in a cafe, I became aware of a strange sensation in my chest. It was as if an agitated finch was trapped in my upper ribcage. Still wearing my heart rate monitor, I watched my heart rate yo-yo between 70bpm and 280bpm.

I ran 50m up the beach hoping it would reset. It didn’t. In fact, I was now feeling positively unusual. Fearing the worst, I walked back to the café and asked the waiter to call an ambulance. Two hours later I was lying in a hospital bed in Exeter, encircled by junior doctors taking turns to peer at me, then at the folds of thermal paper spewing from a nearby ECG machine. “The trace, it’s all over the place,” blurted one doctor with enthusiastic incredulity. “Can I go home?” I asked meekly. “You’re kidding, right?” he replied. “It’s your heart.” I was in my mid-40s, fit and healthy, but I was about to be diagnosed with a heart condition, something I considered unthinkable at the time. It was an arrhythmia called atrial fibrillation, which according to NHS estimates afflicts around 1.4 million people in the UK, about 2.5% of the population.

How common is arrhythmia for cyclists?

Sonny Colbrelli, Chloé Dygert and Zdeněk Štybar are just a few of the pro cyclists who have suffered arrhythmias in recent years. The term arrhythmia means an abnormal heart rhythm, and there are many kinds. Symptoms vary from unusually slow to exceptionally fast beats, which may be regular or wildly irregular. Some arrhythmias are almost entirely benign, others carry mild to moderate risks, and a few can result in sudden death.