Five-day continental shift

But one of the highlights of the gruelling self-set challenge was hearing about people who’d never exercised before notching up thousands of kilometres back home.

For as part of his charity fundraising record attempt, the former Hawick, Galashiels and Borders General Hospital doctor urged non-exercisers and others to get physically active for 30 minutes over seven days.

Dr Murray said: “More than 2,000 folk got involved (walking, cycling or running over the same period as his ultra-marathon challenge). For many it was the first time they had contemplated exercising, let alone doing it. One of the highlights was getting the feedback from folk back home, it was really welcome hearing things like that.

“A lot of people said: ‘I saw you running out in Antartica and thought, well, Edinburgh and Earlston are not so bad, I’ll get out there anyway.’”

He set a new course record in his first run in the world’s southernmost marathon, the Antartic Ice Marathon, which he raced in sub-zero temperatures and katabatic winds to win in three hours, 41 minutes and eight seconds.

Dr Murray said: “Antartica is a savage place, it’s beautiful, a wild frontier. The mountains are enormous and the glaciers are a kilometre thick.

“Another real highlight was arriving at the pyramids of Egypt at dawn, having done the hard work to get there rather than arriving off a coach. It was really special, it was spectacular.

“Arriving at Sydney before St Andrew’s Night and sitting having a dram in front of the opera house was fantastic as well!”

He ran an additional 50km (31 miles) in Antarctica on the Union Glacier before flying to Santiago, Chile, where he completed 50km in temperatures of 50 degrees Celsius warmer than the previous day in Antartica.

The rest of the challenge saw him running a minimum of 50km in each continent, notching up the mileage in Atlanta in the US and around London, before he ran in Cairo to the pyramids, and in Dubai and Sydney, where he celebrated finishing at the city’s opera house.

The 32-year-old ate 7,000 calories per day, travelled more than 43,000km and slept for only 10-and-a-half hours over the five days, 13 hours and 28 minutes.

Asked about the tough bits, he said: “Everything’s challenging, what’s not challenging about running ultra-marathons? And the logistics, but by far the most difficult was the jetlag and lack of sleep. Two hours a night isn’t great and if you are running an ultra-marathon you are even more tired. You are constantly on your feet, on planes, in check-in – they were stinging a bit by the end.”

He said he wasn’t suggesting people run ultra-marathons, but hopes his running will inspire others to get active.

The GP, who is also the Scottish Government’s physical activity champion, said: “Absolutely everything counts, whether it’s walking to work or whatever, every single step is a step to health and it makes a massive difference.

“Exercise also brings quality of life. Every single study says it makes you happy, it releases happy hormones. You might find the actual exercise difficult the first couple of days, but it can be the single best thing people do.”

He also raised £7,400 for the Scottish Association for Mental Health (SAMH).

He told us: “SAMH is a fantastic charity and I’m really proud to support them. They are doing the right thing. They are raising awareness of mental health issues and getting folk active: that by itself improves mental health – the link is really tangible and really important.

“The single best thing people can do for their health is exercise.”

Last year, Dr Murray hit the headlines when he ran 2,659 miles – averaging more than 34 miles a day – from Scotland to the Sahara in 77 days.

He was recently in the Borders when he ran some of the Borders Abbeys Way.

“Borders people are really genuine and honest people and they have got a real pride in the Borders and they take a pride in themselves. If they think physical activity is a way they can create health, they are likely to respond to that and the natural resources of the Borders make it a fantastic place to go walking. If you walk more often you will be more fit, it is as simple as that.”

And he urged locals to Google ‘23 and a half hours’ and watch the animation film created by a fellow medic highlighting the benefits of exercise.