IF YOU feel you have suffered extremes of temperature in recent days, spare a thought for Scotland's fitness czar, Dr Andrew Murray.

Dr Murray, who was appointed by the Scottish Government, completed an epic, 77-day run from John O'Groats to Southern Morocco – the equivalent of 100 marathons, averaging 34 miles a day – in January, arriving in temperatures of 35ºC (95ºF).

Having recovered from his exertions, which raised money to tackle poverty in Mongolia, Dr Murray takes part today in the North Pole Marathon, running across the frozen Arctic where temperatures can plummet to -30ºC.

The Edinburgh-based locum GP was recruited on a six-month secondment by the Government after returning from Africa to act as the country's Physical Activity Champion. He looks at ways of encouraging people to do more exercise – not just running, but walking, cycling or taking part in team sports.

This is the seventh year of the self-styled "World's Coolest Marathon" and Dr Murray is one of 40 competitors representing 14 nationalities who will have to overcome the extreme sub-zero temperatures to finish 26.2 miles in one of the remotest parts of the planet, running across the ice in the high Arctic Ocean.

Dr Murray, who will also be acting as race doctor, is encouraging Scots to follow his example and get active over the Easter break.

He said: "Getting active and staying active is such an important message, we are taking it to the ends of the earth.

"It's great to hear competitors promoting the value of physical activity at this event. The North Pole Marathon is an experience of a lifetime.

"Whilst running, the views and the shapes of the ice are the best painkillers. What the race encapsulates is the sheer determination of everyone to succeed."

He added: "Remember that everything counts – any form of activity 30 minutes a day will help massively. I urge everyone to get active over the Easter break. Running at the North Pole is similar underfoot to running through bogs in the Highlands – although it's a fair bit colder."

Irishman Richard Donovan is the race director and the first man to run marathons at both the North and South Poles. He said: "This is a truly international event, with at least 18 nationalities taking part. We have had some amazing characters and athletes previously, and this year is no exception.

"It's a genuine challenge, running in temperatures likely to be -30ºC, and running not on land, but the frozen Arctic Ocean. But with determination, and the right training, it is achievable. Keeping active is definitely one of the best ways of keeping healthy, although there are easier ways of going about it than running a marathon at the North Pole."

Sport Minister Shona Robison said: "We want to make Scotland a fitter and healthier nation and I hope that other Scots can be inspired by Dr Murray's example by getting active over the holiday weekend.

"By increasing levels of physical activity we can make serious inroads into tackling some of the serious challenges facing Scotland's population, not least the health implications that arise from being inactive."

One of Dr Murray's first roles as Physical Activity Champion was to launch Take Life On, a campaign to promote the benefits of children participating in 60 minutes of exercise a day.

He said at the time: "Being physically active improves achievement and concentration at school, and also prevents heart disease, type-2 diabetes, and cancer in later life. It is the single best present you can give your children.

"Just 60 minutes of physical activity a day will help your children become healthier, happier adults."