That was partly what saved an Uruguayan man who had been lost in the Andes mountains since May, said Singaporean adventurer David Lim.
Mr Raul Gomez Cincunegui, 58, was found near the Argentina-Chile border, where the Ojos del Salado is.
He survived by feeding on rats and raisins he had with him, and leftovers he found in mountain shelters, according to an Argentinian police report.
Mr Lim, 49, who climbed the world's highest active volcano in 2005, said this was very fortunate.
"He must have stumbled upon some food people happened to leave behind," Mr Lim added.
"They're not government-built shelters fully stocked with supplies. Most of them don't even have a roof.
"Those shelters are just small stone sheds with nothing inside."
The shelters were meant for horse wranglers who take their herd up to the mountains to feed during summer.
Mr Cincunegui was spotted at the Sardina mountain shelter on Sunday, at an altitude of some 4,500m in the Los Patos Sur valley.
Police transferred him by helicopter to a hospital in San Juan province.
San Juan Governor Jose Luis Gioja said it was an incredible feat. "It's a miracle," he told AFP.
Rawson Hospital chief of operations Victor Olmos said Mr Cincunegui was recovering in the intensive care unit but was "only dehydrated" and otherwise in good health.
He also showed signs of malnutrition.
Said the governor: "I still cannot believe it. He came here and spoke by phone with his wife, his mother and daughter. He was very excited, though exhausted."
Mr Lim echoed the governor's feelings, saying that even with luck on one's side, it was still a tremendous feat to survive such an ordeal.
"Wow. I can't believe someone actually survived that," he said, adding that the sub-zero winter is the harshest from June to August.
The temperature at an altitude of 4,500m - the height Mr Gomez was found at - could go as low as -15 deg C. The wind chill has to be taken into account, too.
Mr Lim, whose legs are partially disabled, had climbed the peak in the middle of summer in February.
Even then, he said the temperature was just below zero at that altitude.
"At one camp I made, there was frost each morning," he said, describing the terrain as rugged and uninhabited.
"If you get lost there, that's it. You could take weeks to walk out."
Mr Cincunegui was reported missing in May after he went travelling by motorcycle from Uruguay to Chile, reported AFP.
His motorcycle broke down so he decided to cross the Andes on foot.
He said he became disoriented after heavy snowfall and got lost.
A search for Mr Cincunegui was called off in July due to heavy snowstorms. But Mr Cincunegui had a vital survival weapon - the will to live.
"That's the thing that keeps you alive most of all," said Mr Lim.
"It probably kept him alive, too."
Mr Cincunegui's case recalled the flight disaster in 1972, when a charter plane carrying members of the Old Christians rugby team of Uruguay crashed in the Andes.
The accident left 29 dead - some due to the crash and others because of an avalanche. There were 16 survivors, who stayed alive by eating the flesh of their dead friends.
They were rescued after 72 days of being stranded in the harsh, high-altitude mountain conditions.
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