HE's almost 80, has been battling cancer for 17 years and has recently completed a course of chemotherapy, but it seems that nothing can slow down veteran triathlete Brian Grierson down.

In fact, the 79-year-old from Rownhams recently shaved a minute off of his best time in the national Swimathon event, which this year he took part in for Cancer Research.

Brian found out that he had prostate cancer in 2002, when he asked for a blood test, despite having no symptoms, after two good friends were diagnosed with the disease.

He had his prostate removed but later tests revealed rising levels of PSA (prostate-specific antigen), indicating that there was still cancer in his body.

Since then, he has had radiotherapy, chemotherapy and ongoing hormone treatment, to keep the cancer at bay.

"I have to thank Southampton General Hospital for keeping me alive all this time," says Brian.

"I haven't let having cancer stop me."

In fact, the father of two and grandfather of one says that it has motivated him.

Brian has numerous triathlons, aquathlons (swimming and running) and duathlon (running and cycling) under his belt, along with a clutch of medals.

Before he began his recent course of chemotherapy, he set himself the challenge of running the Eastleigh 10k and taking part in the National Swimathon, after the treatment was finished, both of which took place last month.

He hopes to inspire other men to be tested for prostate cancer and to encourage others with cancer to take up sport.

"I want to make people more aware of prostate cancer," he says.

"We are lucky to have a very good hospital on our doorstep – they have an elite medical team there, at Southampton General Hospital.

"My cancer is incurable, but it's treatable. The aim is to control the growth.

"And I think the secret of my survival is sport; I don't think I'd have been here this long without it. I like to have something to train towards."

Brian has asked his doctors if he needs to train less but has been told that he can carry on doing what he loves.

His training schedule is impressive.

Every week he cycles 100 miles, swims 5k at Oaklands Community Pool, and runs 10 to 15k, generally doing something every day, and has also begun volunteering as a gardener at Oaklands.

He's working towards taking part in a triathlon and an aquathlon later this year.

"I'm competitive, and like to give it my best," he says.

"The cancer has probably kept my motivation high. If my days are numbered, I've had a good life."