The Huffington Post:  To those of us who are satisfied with a jog on the treadmill or a 45-minute yoga class, endurance adventures like running 100 miles or swimming from Cuba to Florida can sound plain crazy.

Which is part of what makes Lewis Pugh’s accomplishments all the more impressive, considering the wisdom he has gathered through his extreme swims.

Pugh, who has swum in every ocean in the world, was also the first person to complete a long-distance swim at the North Pole, where waters are below zero degrees centigrade — the freezing point for fresh water, Mashable pointed out.

This week, he’s joining global leaders at the 2014 annual meeting of the World Economic Forum in Davos, Switzerland to share some of the lessons he learned while training and swimming at the North Pole as well as in a lake on Mt Everest. Many, he asserts, also apply to leadership on terra firma.

Called the Human Polar Bear, Pugh has spoken about leadership before, most famously in a 2008 Business Innovation Factory speech named one of the seven most inspiring videos on the Web by Mashable in 2009.

The 36-year-old Londoner spent almost 19 minutes at minus 1.8C as he front crawled for a full kilometre – more than half a mile in the coldest water a human has ever swum.

Pugh

I d-d-d-did it: Pugh emerges after his polar swim

Lewis Gordon Pugh

Lewis races through the icy water

“It was like jumping into a dark black hole,” he said. “The pain was immediate and felt like my body was on fire.

“I was in excruciating pain from beginning to end and I nearly quit on a few occasions. It was without doubt the hardest swim of my life.”

But he said that a colleague ski-ing on pack ice alongside him looking out for hungry polar bears spurred him on.

“I just kept on looking at Jorgen Amundsen ski-ing next to me, encouraging me. I will never ever give up in front of a Norwegian! Let alone a relative of Roald Amundsen (who beat Britain’s Captain Scott to the South Pole.) There is just too much rivalry between our two nations for that.”

Lewis Gordon Pugh

Lewis Pugh stood up to the freezing temperatures

diving

Lewis dives into the icy water

Pugh, who gave up his career as a maritime lawyer to become a full-time endurance swimmer, carried out his latest expedition to highlight how global warming has melted the Arctic ice- caps.

He travelled to the geographic North Pole on a Russian icebreaker with a 29- strong back-up team including a mind coach.

To develop his cold sea swimming technique he practised in a pool filled every day with a ton and a half of ice.

He has broken more than 20 endurance swimming records which include the first swim of more than 1km in the Antarctic Ocean.

He has swum the whole of the Thames, been first to swim the length of the world’s longest fjord and first to swim round the most northerly point of Europe.

He is also the first man to swim at the South Pole – where the waters are a comparatively warm zero celsius.

Although the North Pole temperature is below zero, the salt is enough to prevent the water freezing at that temperature.

Pugh carries out his swims to Channel Swimming Club rules – which outlaw wetsuits, flippers or snorkels.

He chooses not to cover himself in goose grease as he does not want to be too slippery for his team to fish him out of the water in case he develops hypothermia.

• Lewis Pugh’s incredible ability to withstand the icy cold has been developed over years of training.

Before he dives in, he spends around 15 minutes using mind power alone to superheat his body.

His pulse rate shoots up from 70 to 160 a minute and his temperature rises from 37C to 38.4, causing him to sweat profusely.

This is all without moving a muscle – and something which would take an ordinary person around 30 minutes of hard exercise to achieve.

He also plays aggressive rap music – Eminem is a particular favourite.

Describing the feeling of swimming in water more suited to seals, whales and polar bears, he said: “Before I get in, my body feels like a furnace. I become very aggressive, and my surroundings seem to slow down. Then I hurl myself in.

“At first, you experience massive hyperventilation. Controlling this is extremely difficult.”

On leaving the water yesterday, his core body temperature had fallen to 36.5 degrees and it dropped further to 35 degrees 20 minutes later but a warm shower enabled him to return to normal.