Mr Peter Lim Kok Seng, 54, used to look forward to his weekly swim at Hougang or Serangoon Swimming Complex. Now, he cannot run after the bus or lift heavy things, and he is limited to a quick dip in the pool.
The muscles around his abdomen still feel weak after a 10-hour transplant surgery that took place at the National University Hospital on March 24.
Mr Lim had donated 60 per cent of his liver to a 16-year-old girl he had not met before. The procedure left an L-shaped scar, which is about 15cm by 15cm, on his lower abdomen. He is the first non-directed liver donor in Singapore's 26 years of carrying out liver transplants.
This means that he did not have a specific person in mind when he donated his liver. He was moved by what he saw at a liver disease centre at Singapore General Hospital two years ago.
"I felt sad when I saw so many of them, all waiting to be treated for liver disease. Unlike kidney failure, there are no procedures like dialysis that can keep them alive if their livers fail, " he said.
He then came forward to donate his liver to someone on the national waiting list who needed it most.
Mr Lim, who is a Christian, decided to be a non-directed donor to express his gratitude, as his second daughter was born 12 years earlier with no complications. Mr Lim's wife was then in her 40s.
His other daughter is 26.
In January, a match was found in 16-year-old Lim Si Jia, whose liver was unable to properly break down a compound called glycogen.
Left untreated, her condition could lead to cancerous tumours forming on her liver, which could be fatal in the long run.
Potential donors go through a lengthy counselling process over several months, are told of the risks and given the option to back out.
The identities of both donor and recipient are also kept from each other until after the operation and are made known when both are agreeable to being identified. This is to avoid feelings of obligation.
For the donor, the surgery carries a 15 to 20 per cent risk of complications. The risk of liver failure is less than 1 per cent.
After surgery, Mr Lim was on medical leave for six weeks without pay because he was a daily-rated employee. The security concierge at the Marina Bay Financial Centre, who was working day shifts for about $2,500, switched to a less demanding job as a night-shift security officer for about $2,000 a month.
His liver has since regenerated and, in June, he met Si Jia for the first time. She is recovering well.
He said: "You can never change the world from what it is, but we can play our part in small ways, and make life better for others if we want to."