Dennis Thorpe, a retired carpenter and joiner, took part in the Great West Run in Exeter not only to raise funds for the unit but also to make the public aware of the need for organ donation.
This month he has been in training, encouraged by his wife, Christine, in preparation for a distance he has never run before.
Dennis was inspired to run by his neighbour and friend Wendy Sincock.
She is the Exeter district transplant team manager and herself a recipient of a kidney, which she says has transformed her life.
More than 6,000 transplants, such as hearts, kidneys and lungs, are needed in this country every year to meet demand from those awaiting an organ.
Wendy, 50, said: 'It is absolutely marvellous what Dennis is doing, especially at his age and it is very much appreciated.
'Before I had my transplant 12 years ago I was on dialysis and I could hardly make it up the stairs. Now after receiving a kidney I enjoy swimming, cycling, canoeing — I even shot putt. It has given me a new lease of life.
'We are very grateful to Dennis for doing this run and appreciate all the hard work he has put in.'
If you would like to sponsor Dennis's superb effort for the kidney unit please make a donation to the Exeter Kidney Patients' Association, c/o Dennis Thorpe, The Willows, Spreyton, Crediton EX17 5AL.