Last spring, Ravuth Thorng, then just 24, noticed it was increasingly difficult to do ordinary tasks, such as walking to his car.
“I felt out of breath walking from my parking spot to work,” says Thorng, who worked at a home improvement store in Rochester, Minn.
In retrospect, he recalls that during the previous winter, he couldn’t push a shovel full of snow more than five feet before getting chest discomfort and shortness of breath. He shrugged off the chest pain. “At my age, I didn’t think it’d be anything serious,” he says. “I thought it was heartburn.”