When a 24-year-old man showed up at a British hospital emergency room with chest pains, doctors also heard a loud crunching sound each time his heart beat and felt air bubbles under his skin. According to the British Medical Journal, the patient disclosed that the day before he had blown up about 20 party balloons. Doctors concluded that the man had burst some of the little air sacs in his lungs when he blew up the first balloon, then inflated himself a little bit more each time he blew up another balloon. His symptoms cleared up within 10 days.