The hidden AF risk for midlife cyclists—and how to ride with it

Midlife endurance cyclists have a higher risk of atrial fibrillation (AF), a common heart rhythm disorder linked to decades of riding and an enlarged left atrium. AF can cause sudden drops in power and dizziness during rides, but it’s treatable with medications, rhythm-control strategies, and sometimes ablation. Prevention isn’t foolproof, but risk can be managed through moderate training, healthy weight and blood pressure, good sleep, limiting alcohol around workouts, and treating related conditions like sleep apnea.