When he was a child, Mr Toh Poh Joo went through school not knowing on which days he would have money to buy food during recess.

His father, a butcher, and his mother, a factory worker by night - who looked after neighbours' children in the day - struggled to support three children.

Mr Toh was the youngest and, on the days when his parents could not give him pocket money, he would drink tap water in school to fill his stomach, and play with his friends to forget the hunger.

Now 41, married and working as vice-president of terminal management for the Changi Airport Group, going hungry is no longer an issue. But he has not forgotten what it feels like to go to school with empty pockets.

He hopes to raise $50,000 for The Straits Times School Pocket Money Fund by taking part in an Arctic race that starts this Friday. It requires him to cover 566km on foot in eight days, pulling his provisions in a cart and braving freezing temperatures as low as -40 deg C. The distance is equivalent to going around Singapore 2.5 times.

He left last Friday for Yukon, Canada, where the race starts. He will then join 11 others who will make their way to Tuktoyaktuk, Canada. Mr Toh is the only Singaporean and only Asian in the race.

He said: "When I heard about the pocket money fund, I remembered what I'd gone through when I was a kid, not having money to eat."

For the race, he has spent a total of$10,000 on food and gear alone, out of his own pocket.

It is not the first time that Mr Toh has raised money for the ST School Pocket Money Fund. He raised $53,000 in 2008 by running from mall to mall, selling towels and mugs, and getting volunteers from junior colleges to help him sell flags. Of the total sum he raised, part of it, or $25,000, was contributed by the CapitaLand Hope Foundation.

The expedition this time will be his second attempt to complete the Arctic race. He, along with five out of eight others, did not finish it in his first attempt in 2010.

But, with experience gained from it and the two other Arctic races in which he took part later, he is ready to try again.

In the 2010 attempt, he did not expect conditions to be so extreme. He said: "Food actually burns your tongue, because it's so cold."

He has now learnt to put food in his jacket for at least 10 minutes to warm it up before eating.

Most of his diet will also be liquid-based this time. He said: "It's more easily absorbed by the body, and will keep me hydrated."

Extreme dryness had caused painful cracks on his feet in the last race. He plans to apply petroleum jelly this time round, which stays on longer than normal moisturiser.

He has been training daily to prepare for the upcoming race. On weekdays from 4.30am to 6.30am, he pulls the cart he will be using - with up to 30kg of water in it - up Bukit Batok Hill. On weekends, he walks 46km from Upper Bukit Timah where he lives to Changi Village, starting at 4am.

His wife of two months, Ms Linda Loh, 36, supports him fully in his efforts. She buys him food and also trains with him on weekends.

Said the management consultant: "He has always had a big heart for charity. I think it's great that he can tie his passion for adventure with something so personally meaningful for him."

The ST School Pocket Money Fund provides pocket money to children from low-income families. They can use the money for school-related expenses, such as buying food during recess or paying for transport. It supports about 14,000 children and youth a year.

On Mr Toh's efforts, Mr Warren Fernandez, chairman of the fund and editor of The Straits Times, said: "Poh Joo's attempt at this amazing feat is awe-inspiring, and his thoughtfulness in doing it to help a good cause is truly commendable. We salute his effort, and wish him all the best in achieving his goal."

The public can donate online until March 31 via the portal Giving.sg managed by the National Volunteer And Philanthropy Centre. The portal also facilitates fundraising and volunteerism.

Recalling his school days, Mr Toh said: "When the stomach is growling, you can't really concentrate. I feel for kids who have to go through it every day."

• To make a donation and find out more about Mr Toh Poh Joo's Arctic expedition, visit www.giving.sg/the-straits-times-school-pocket-money-fund/arcticchallenge