An 80-year-old Japanese man who underwent heart surgery in January reached the summit of Mount Everest on Thursday, becoming the oldest person to scale the world's highest mountain.

Yuichiro Miura and his party, including his second son Gouta, arrived at the summit at around 9 am local time (0315 GMT), according to Miura's website, besting the previous age record by four years.

But he may not have his name on the title very long: Nepal's Min Bahadur Sherchan, the former record holder who turns 82 on June 20, is on the mountain again and bidding to reach the summit.

Video: Japanese Sport Botaoshi Explained

"I feel like the happiest person in the world," Miura said in a satellite telephone conversation with his office in Tokyo. "I've never been more exhausted than this but I can keep on going even at the age of 80.

"I can see the Himalayas below me and it's beautiful. I have stayed strong, strong and strong to be here," he said.

His wife Tomoko, 80, told the adventurer: "You'd better come home soon."

"I'm not sure if I am happy or not to have a husband who has so many dreams," she told reporters. "He is the kind of person who does whatever he believes in, no matter what other people say."

His daughter Emiri, 52, said: "I believe he will keep on going even when he turns 90 or 100."

Video: Can Science Stop Aging?

Miura was on his way back down the mountain Thursday, a Nepalese tourism official said, confirming the successful ascent.

"He reached the summit this morning and is currently descending to Camp Four," the official, Gyanendra Shrestha, told AFP from Everest Base Camp.

Banner headlines in Japanese evening papers proclaimed the elderly adventurer's success and television news carried extensive coverage of the feat, which was widely celebrated in a nation increasingly dominated by older people.

It was Miura's third conquest of the 8,848-metre (29,028-foot) peak.

He previously reached the summit in 2003 and 2008 when he was 70, claiming the oldest summiteer record, and 75 respectively.

His 2003 record was broken in 2007 when fellow Japanese Katsusuke Yanagisawa reached the top at the age of 71.

His second conquest of Everest was made in May 2008 but he was beaten to the summit by Sherchan, who had got there just one day earlier at the age of 76.

Until Thursday morning the Nepalese had been the world record holder, according to Guinness World Records.

Sherchan is at base camp and preparing to make his ascent, Nepalese official Shrestha told AFP, adding time was not on his side since the fair weather summit season is drawing to a close.

Yuichiro Miura in 2003 after he summited Everest at age 70.Reuters/CORBIS

Miura underwent surgery to correct recurring arrhythmia last November and again in January this year, as he did before the 2008 expedition. He was undeterred by a skiing accident in 2009 that left him with a broken pelvis and fractured thigh.

As a seasoned adventurer, he came to worldwide attention in 1970 when he became the first person to ski down Everest.

His parachute-aided descent was documented in the 1975 film "The Man Who Skied Down Everest," which won an Academy Award for Best Documentary.

Video: Wingsuit Flying Explained

High-octane endeavors are in his blood -- his father Keizo skied down Mont Blanc at the age of 99.

More than 3,000 people have successfully scaled Everest but more than 300 have died on the mountain since it was first conquered by Edmund Hillary and Tenzing Norgay in 1953.

Underlining the hostility of the area, five climbers were reported missing, feared dead on the treacherous Kanchenjunga mountain, tourism officials said Thursday.

The climbers -- two from Hungary, two from Nepal and one from South Korea -- went missing on Monday afternoon as they attempted to climb the 8,586-meter (28,169-foot) peak, the officials said.