Miura is a Japanese alpinist who in 2003, at age 70, became the oldest person to reach the summit of Mount Everest. This record was later broken by himself. Miura had two heart surgeries for cardiac arrhythmia, in 2006 and 2007. On May 23, 2013 Miura again became the oldest person to climb to the summit of Mount Everest at the age of 80. This achievement is listed in the Guinness Book of Records. He was unable to make the descent after reaching the top, and was airlifted from Advanced Base Camp at 6500 meters, not walking down to the Base Camp at 5364 metre (17,600 feet). Famous alpinists, like Ken Noguchi, question Miura's achievement and say that a climb can not be called complete unless one walks all the way down the mountain.