While most people her age are slowing down, 64-year-old Gloria Lau is speeding up.
Since her first marathon in 2007, she has run in about 20 marathons in over a dozen countries across all seven continents.
Come April 9, the mother of two will take part in the North Pole Marathon. When she first attempted this last year, she did not complete the full distance of 42.195km.
She managed to cover 28km, and qualified for the Half Marathon Grand Slam Club - for those who complete a marathon on each of the seven continents and half a marathon on the Arctic Ocean.
She has been running to raise funds for charity - she said people can tell her which charity they want to donate to, and she will match the amount dollar for dollar. Through various marathons, she has matched about $150,000.
She told The Straits Times: "I feel it's unfair to contribute only to the causes I support. Any cause is a good cause."
When she took part in the North Pole Marathon last year, she was the oldest runner to attempt it. This year, besides Ms Lau, two other Singaporeans will be taking part in the race.
For Ms Lau, despite having run in Antarctica, she sees running in the North Pole as a different challenge.
"In Antarctica, the snow is more dense. But the snow in the North Pole is like icing powder. The moment you put your foot in, you just sink. Snow got into my shoes, and after a while, they became totally drenched," she said.
'World's coolest marathon'
Dubbed the "world's coolest marathon" by leading running magazine Runner's World, the first competitive edition of the North Pole Marathon was held in 2003.
Race director and Irish marathon runner Richard Donovan ran the distance alone in 2002.
The North Pole is not situated on land, but on frozen water in the Arctic Ocean. So the entire race course moves with the direction of the ocean current during the race.
About 400 people from more than 40 countries have completed the race since 2003. Mr Donovan finished the distance in 3hr 48min 12sec in 2002.
The men's record of 3hr 36min 10sec was set by Mr Thomas Maguire of Ireland in 2007. The women's record of 4hr 52min 45sec was set by Ms Anne-Marie Flammersfeld of Germany in 2014.
Dr William Tan, who completed the race in a wheelchair in 2007, was the first Singaporean to attempt it.
Her goggles also fogged up last year, and when she switched to sunglasses, her face was exposed and she developed frostbite. The wind chill also meant that temperatures fell further to about minus 55 deg C.
Given the low visibility and the slight hypothermia she developed, she decided not to stretch her run out to a full marathon.
Now equipped with a more suitable pair of shoes, she is determined to complete the full distance.
"I've only done full marathons overseas. It wasn't my plan to do a half-marathon," she said.
She was not always a sports enthusiast. She started exercising regularly when she was 56, after her doctor told her to do weight- bearing exercises as she had low bone density. She took long walks, but that got boring, so she started jogging and eventually ran in her first marathon in Perth in 2007, completing it in 4hr 50min.
Ms Lau, who runs a property development business, enjoys running overseas and sees it as a way of taking in the sights in ways not possible if one were to travel by car.
She has been running a marathon a month since last November.
"That also means I don't really have to train any more!" she said.
She hopes to motivate others in her age group to stay active. "In my daily life, I can deal with anything now after putting myself through all these challenges."
• To support Ms Lau's fund-raising efforts, e-mail her at firstname.lastname@example.org