NEWS Shopper has been following the exploits of a self-confessed couch potato turned athlete extraordinaire and can now report he has completed his gruelling challenge.

Mark Gunnell, 36, started training for a four-event challenge as a form of New Year's resolution.

Last month he completed the Blenheim Palace triathlon, the Exeter triathlon and the London to Brighton bike ride.

However, the driving instructor still had the toughest part of the challenge to go but he faced his demons to complete the mammoth London Olympic Triathlon and raise £600 for the Alzheimer's Society at the same time - a charity chosen after his wife Penny lost her mother to the disease in April.

The father of two from Slade Green said: "Two weeks before the race I should have been bulking up on carbohydrates but I hardly anything because I was sick with nerves."

It is no surprise he suffered as the London Olympic Triathlon consists of a mile swim in the Thames, a 40km bike ride and a 10km run - almost double any of the previous challenges.

Mark said: "On the eve of the triathlon I was sick but then suddenly I had registered my bike on the morning of the race and was waiting to start.

"I did the mile swim in 30 minutes and the bike ride in one hour 34 minutes both of which matched my best times in training but the 10km run was tough.

"My quickest time in training was 53 minutes and my slowest was one hour 15 minutes. On the day I did one hour 13 minutes.

"I was on course for another personal best but with 2km to go I hit a pain barrier, could barely run at all and kept stopping to take on water."

He added: "I weighed myself before and after the event and I had lost 13lbs in fluid and I had drunk four litres during the triathlon too."

"By the end of the run I felt dizzy and sick as if I was drunk but moreover I was elated to have completely my eight-month goal."

Prior to taking on the challenge Mark had spent 18 years sitting on his sofa and so he knows the struggle of getting off your bum.

He said: "Too often people give up New Year's resolutions but with my four-event challenge I kept getting out of bed to train even when I was tired.

"I felt fine once I was training but getting off your behind is the hardest part.

"I want to keep training and do more triathlons otherwise I will be a couch potato again."

But in a scene reminiscent of Sir Steve Redgrave's pledge never to climb into a rowing boat, Mark says: "The Olympic triathlon is my limit, so if you hear of me doing something stupid such as the Iron Man Triathlon, shoot me."

However, with Mark having been bitten by the bug I suggest we watch him closely, guns loaded and primed.