Giving up his time to train for a marathon is a small sacrifice compared to what has gone before.
Thurso man Martin Crouden gave the gift of life to a complete stranger in May by donating one of his kidneys.
The 30-year-old is one of a small number of people to become living kidney donors since it became legal in the UK back in 2006.
And he is taking part in the Baxters Loch Ness Marathon in September to show people that you can carry on and have a normal life after going through the procedure.
Mr Crouden said: “I feel tip top. I’m just lacking in strength and energy a bit, but I’ve started to do some low-level training for the marathon.
“I go for a walk every morning and managed to go for a half mile jog this week. I don’t care what time it takes me to finish, whether it’s six or 16 hours, but I will cross the finish line at Bught Park in Inverness.
“A lot of people don’t realise you can be an altruistic donor as leaflets about it don’t come through the door.
“I want to raise awareness as well as raising money for the charity Kidney Care UK.”
Mr Crouden’s decision to donate one of his kidneys didn’t happen overnight.
“I saw something about altruistic donations on Facebook about five years ago and started to think about it then.
“My maternal grandfather died when he was just 30 as a result of cancer of the kidney. My Mum was only four at the time.
“If a transplant had been available then, he would still be alive today, so this was one of the main reasons why I wanted to go through with it.”
Mr Crouden took up running in order to lose weight before the operation and took part in the Baxters Loch Ness Marathon for the first time last year.
He also had to go through a screening process to make sure his kidney was suitable.
“When I got back from hospital, I received a letter from the recipient’s sister thanking me for making the donation. I was really grateful to receive this and a few weeks later I was sent a few paragraphs from the recipient herself. She was a nurse and said she is doing well and thinks about me often.
“I have started to write back, but it’s difficult to put down in words what I want to say. But I’ll post it one day.”
The Baxters Loch Ness Marathon is on Sunday, September 24.