“YOUR heart rate is high, the wet suit is tight, your blood is coming back to your hands and feet and the helmet’s got to go on.”

Welcome to the world of triathlon, a uniquely challenging discipline.

Those are the words of Steven Smith, chairman of Oxford Triathlon Club.

The origins or the sport, which combines swimming, cycling and running, are unclear, but it was developed in the USA in the 1970s, and joined the Olympics in 2000.

Oxfordshire not only has several triathlon clubs across, but also the annual Blenheim Palace Triathlon, one of the sport’s biggest events.

Oxford Tri is next month starting training sessions for this year’s race at the palace, held on June 8 and 9.

The club, which is 25 years old this year, has 200 members, but this number goes up to 300 every summer, when the idea of open water swimming becomes more palatable.

The easy course on the Blenheim Triathlon starts with a chilling 400-metre swim through the lake in the palace grounds.

“It is a melee,” says Mr Smith, “waves of people, 200 at a time, all bobbing in the water, then the klaxon goes off and all those people start splashing around, you get knocked around, you might get a foot in your face.

“It’s the washing machine effect, that is the introduction you get.”

Then comes the first transition – you get out of the water, your bike is set up ready for you, and you have to get out of your wet suit as fast as possible.

The 13.2km bike ride, twice around Blenheim’s grounds (in the Olympics it’s 40km), is followed by a 2.9km run.

“Doing these sports all together is very different to doing them separately,” added Mr Smith. “We train specifically for those transitions.

“For example, when you finish the bike ride it can take a while for your legs to catch up and start running, so we train people to cycle in a particular way so as to spare the quadriceps and hamstrings for running.”

Last year, eight of the club’s members competed in the World Championships in New Zealand.

They all have full time jobs, and paid for their own plane fares.

The club has 12 qualified triathlon coaches who run training sessions each week.

In May, it is running a series of training events for the Blenheim Triathlon at Dorchester Sailing Lake.

And the Oxford Mail has a special link with the event after former reporter Emma-Kate Lidbury made it as a professional triathlete.

Miss Lidbury took up the sport in 2005 after participating in the first Blenheim Triathlon as part of her job as a journalist at the Oxford Mail and the Oxford Times.

She is now a five-time Ironman 70.3 champion based in Santa Monica, Southern California.

Team GB picked up a gold and a bronze medal in the London 2012 Olympics.

To find out more go to oxfordtri.co.uk