Why does my chest burn after running?

The likely culprit is your airways, not your heart - but both deserve a sentence. When you run, you breathe faster and through your mouth, which skips the nose's job of warming and humidifying air. Cold, dry air hitting your airways directly can make them tighten, and MedlinePlus names exercise-induced asthma as happening during physical exercise, especially when the air is dry - the NHS likewise lists exercise and cold air among common asthma triggers. The result is burning in the chest, a cough, wheeze, or unusual breathlessness that eases within minutes of stopping. Plenty of people have this exercise response without a formal asthma diagnosis, and it is manageable: warm up gradually for 10 to 15 minutes, breathe through a buff or scarf in cold weather, and see a GP if it happens regularly - a reliever inhaler used before exercise is standard, effective treatment. Now the heart sentence, because it matters: the NHS says to call 911 for chest pain or discomfort that does not go away, feels like squeezing or pressure, or spreads to the arms, back, neck, or jaw. Chest burning that arrives at a predictable pace and fades with rest in someone over 40 or with heart risk factors deserves a GP visit, not assumptions - angina can masquerade as a burn. Young, otherwise healthy, cold-air-only burn that vanishes when you stop is the airway pattern. Pymander is a free AI doctor, 24/7 by text, that can help you weigh which one you have.