Quantity surveyor Amy Wong Kum Ling, 46, who died of altitude sickness last Friday on her way to Mount Everest's base camp, was an avid trail runner who loved the outdoors.
She had arrived just one day earlier with friends at Lobuche, a small Nepalese village near Mount Everest at an altitude of about 4,940m. She was there to take part in the Tenzing Hillary Everest Marathon - billed as the world's highest marathon - which starts today from the base camp at an altitude of 5,364m.
According to the Solukhumbu District Police Office, she died in her hotel room on Friday morning.
Her friend Khoo Zhihao, 34, said Ms Wong had been an active member of the ultra-running community. Ultra-runs typically refer to runs that are longer than 50km.
"She was a wonderful lady - very healthy and very strong in terms of fitness," said Mr Khoo, an athletics coach.
He said her death came as a shock as she had previously made a successful trip to the base camp in 2012, and had no health issues or medical conditions that he knew of. "Condition-wise, she would have been capable of taking on extreme things," he said.
Another friend, Mr Ng Seow Kong, 56, who is the chief executive of an events management company, said Ms Wong had completed several 100km marathons in various locations, including Hong Kong and Montreal, Canada. "She often travelled to take part in sporting events and had the passion for running. She was always up for new adventures in new places," he said.
Her friend Dennis Quek last Saturday posted on Facebook: "While saddened, I am consoled by the fact that she left us peacefully, and doing what she loved most. The mountains called, and she went. Rest in peace my friend."
Ms Wong's older brother told Chinese evening daily Lianhe Wanbao that she had arrived in Nepal two weeks ago. "She relished the freedom of running freely, close to nature," the 49-year-old told Wanbao.
The family is making preparations for Ms Wong's body to be flown to Singapore. It is expected to arrive tomorrow or on Wednesday.
Photographer Stefen Chow, 37, is an experienced mountaineer who scaled the summit of the 8,848m Mount Everest in 2005, and last year did a seven-day trek in the Himalayas with his wife and three-year-old daughter. He said altitude sickness, or acute mountain sickness (AMS), is something even seasoned climbers can succumb to.
"In my past expeditions and experience, I met people who had worrying difficulties even at 4,000m. AMS is very dangerous if you do not heed the symptoms and do not medicate or descend promptly."
Dr David Teo, a medical director at International SOS, a global medical assistance company, said a lack of physical fitness, dehydration and ascending too quickly can increase the risk.
"Travellers to high altitudes often avoid drinking due to the cold and dry environment. They could easily become dehydrated. When signs and symptoms of altitude sickness (such as nausea or giddiness) set in, it is important to rest and stop ascending. If signs and symptoms worsen, start descending."