By Kerry Breen is a news editor at CBSNews.com. A graduate of New York University's Arthur L. Carter School of Journalism, she previously worked at NBC News' TODAY Digital. She covers current events, breaking news and issues including substance use. Read Full Bio April 4, 2026 / 8:00 AM EDT / CBS News Add CBS News on Google When John Cantrell retired, he decided his new job would be staying healthy. He was already in good shape and ate well but he wanted to make sure he could see his grandkids grow up. Already an avid cyclist, he upped his time on the bike and took up pickleball.  Cantrell made sure to go to all his doctor's appointments. When a cardiologist told him he had a heart condition called aortic stenosis in August 2024, he planned to get it treated soon.…