Frank Poole worked out at a gym and hiked around his Mississippi home carrying a weighted pack for months in preparation for his trip to the Grand Canyon. But it wasn't long after Poole started hiking on a popular Grand Canyon trail that he was struggling to breathe. Several hours later, he was in a northern Arizona hospital, where doctors determined the 75-year-old Poole had suffered a heart attack.
http://www.contracostatimes.com/travel/ci_12620637