There are many reasons for getting winded when you climb stairs or exercise. In rare cases, adults can potentially find the culprit is a congenital heart defect or an undiagnosed heart condition that developed before you were born.
Experts estimate about one out of every 150 adults lives with congenital heart disease. Most received treatment when they were very young, often in infancy. But on rare occasions, people don’t find out they have a defect until much later in life.
This happens more among those who were born before hospitals began routine screening of blood oxygen levels in all newborns (using pulse oximetry). (This routine testing was endorsed by the American Academy of Pediatrics, American Hospital Association, and American College of Cardiology in the 2010’s though its use began about a decade earlier.)