Unfortunately for Yuichiro Miura, the 81-year-old Nepalese man who nabbed the record just before he could in 2008 is fast on his heels.
Miura on Wednesday was already in the "death zone," the steep, icy, oxygen-deficient area close to the 8,850-meter (29,035-foot) summit. His rival, Min Bahadur Sherchan, from Nepal, was at the base camp preparing for his own attempt on the summit next week.
On his expedition's website, Miura explained his attempt to scale Everest at such an advanced age: "It is to challenge (my) own ultimate limit. It is to honor the great Mother Nature."
He said a successful climb would raise the bar for what is possible.
"And if the limit of age 80 is at the summit of Mt. Everest, the highest place on earth, one can never be happier," he said.
Miura reached the South Col, the jumping-off point for most final ascents, on Tuesday, according to his website, which also posted pictures of him eating hand-rolled sushi inside a tent.
"Miura is reported to be in good health and he and his team are aiming to reach the summit on Thursday morning," said Gyanendra Shrestha, a Nepalese mountaineering official at the base camp.
If Miura makes it to the top, he would capture the record. But it would only last a few days if Sherchan is able to follow him.
Miura's daughter, Emili Miura, said he "doesn't really care" about the rivalry. "He's doing it for his own challenge," she said.
The situation was not too different five years ago, when, at the age of 75, Miura sought to recapture the title of oldest man to summit the mountain. He had set the record in 2003 at age 70, but it was later broken twice by slightly older Japanese climbers.
He reached the summit on May 26, 2008, at the age of 75 years and 227 days, according to Guinness World Records. But the record eluded him because Sherchan had scaled the summit the day before, at the age of 76 years and 340 days.
Sherchan, a former Gurkha soldier in the British army, first began mountaineering in 1960 when he climbed Mount Dhaulagiri, the 8,167-meter (26,790-foot) high peak in Nepal, according to his grandson, Manoj Guachan. Always an adventurer, and unbowed by age, he walked the length of Nepal in 2003.
Sherchan and his team said Wednesday that they were prepared for their new climb, despite digestive problems he suffered several days ago.
"Our team leader has just arrived back at base camp and we are holding a team meeting on when exactly I will head up to the summit," Sherchan, who uses a hearing aid, said by telephone from the base camp. "I am fine and in good health. I am ready to take up the challenge. Our plan is to reach the summit within one week."
It takes three to four days for climbers to reach Camp 4 on South Col from base camp, and another day to reach the summit.
There are only a few windows of good weather during the climbing season in May for people to attempt the summit. That could favor Miura.
Conditions should be favorable Wednesday and Thursday, but they were expected to deteriorate after Friday, said Shrestha, the mountaineering official at base camp.
Sherchan's team is also facing financial difficulties. It hasn't received the financial help that the Nepal government announced it would provide them. Purna Chandra Bhattarai, chief of Nepal's mountaineering department, said the aid proposal was still under consideration.
Miura faced difficulties of his own.
He fractured his pelvis and left thigh bone in a 2009 skiing accident, and had an operation in January for an irregular heartbeat, or arrhythmia, his fourth heart surgery since 2007, according to Emili Miura.
His daughter said Miura decided to go ahead with the expedition despite the surgery because he felt that at age 80, he was running out of time.
"If he was in his 60s, he probably would have waited for another year or two, but at the age of 80 he's not getting any younger. He has a strong determination that now is the time," she said in a phone interview.
On his ascent, Miura made a stop at the rarely used Camp 5 to take a break between the South Col and the summit. Almost all the climbers these days walk straight from Camp 4 to the summit.
Miura was well-known long before his late-in-life mountaineering pursuits.
He was a daredevil speed skier who skied down Everest's South Col in 1970, using a parachute to brake his descent. The feat was captured in the Oscar-winning 1975 documentary, "The Man Who Skied Down Everest."
In 1964, he briefly set a world speed skiing record in the Italian Alps, reaching 172 kilometers per hour (107 mph). He also skied down Mt. Fuji using parachutes.
It wasn't until Miura was 70, however, that he first climbed all the way to the summit of Everest. When he summited again at 75, he claimed to be the only man to accomplish the feat twice in his 70s. After that, he said he was determined to climb again at age 80.
Miura is accompanied on the expedition by his son Gota, a two-time Olympian skier. Gota Miura, 43, summited Everest in 2003 with his father, but had to turn back short of the summit in 2008 due to symptoms of high altitude cerebral edema.