ULTRAMARATHON runner Dr Andrew Murray is going to extremes to work off the Christmas turkey with a 550-kilometre run across the Namib Desert.

The member of the Royal College of Physicians and Surgeons of Glasgow will face the challenge with Donnie Campbell, a personal trainer, and along the way the pair will also be taking vital medical supplies to local communities.

With the highest sand dunes and the lowest rainfall on the planet, the inhospitable terrain would put most people off but not these two.

Campbell and Murray are no strangers to extreme endurance challenges, with Murray, 34 who also works with SportScotland Institute of Sport having run a phenomenal 2659 miles from John O'Groats to the Sahara, as well as winning races at the North Pole, Antarctica and Outer Mongolia.

And 30-year-old Campbell, a former Royal Marine Commando, once ran 184 miles from Glasgow to Skye non-stop.

They aim to cover more than 50 kilometres per day across the coastal desert, one of the oldest and largest deserts in the world, the Namib stretches inland from the Atlantic Ocean, covering large swathes of Namibia and parts of Angola and South Africa.

"Having run all over the world, I can say hands down the Namib Desert is the most fantastic place we could have chosen," said Dr Murray.

"It is not just putting one foot in front of the other but also a massive science experiment. It is up to us to involve the right people and do the right training to counter the extreme terrain, temperatures, and challenges that emerge."

They expect to about 10.5 litres of water a day, while at the same time to promote the value of regular exercise.

"We're not asking people to run ultramarathons, but with even 150 minutes a week of any exercise, for example walking adding seven years to life, and even five minutes exercise getting the happy hormones going, each step is a step to health and happiness," he added.

"And in Scotland great organisations such as World Walking, 5x50, Paths for All and Ramblers Scotland can help support this."

Campbell says the biggest challenge is training in the Scottish winter for such extreme hot and dry conditions.

"We are both out in the freezing, wet, windy early mornings and this is a far cry from the extreme heat we will face in the Namib Desert," he said.

"It is also only going to get worse as we log 30 hours of running a week during the festive period while everyone else will be relaxing and enjoying a few mulled wines and some turkey.

"This is necessary as to be successful in any challenge the hard work has to be done in the preparation and training when no-one is watching.

"I know when we leave for the Namib Desert we will both be in prime physical condition."

The men start on February 2 and were challenged by veteran expedition leader David Scott to take part in The Namib 550, sponsored by Lyprinol. The event will be supported by expedition organisers Sandbaggers, while Edinburgh based film-makers, BigShot Productions, will be there to document it.