As a blinding stab of pain shot down his spine, Alistair Sutcliffe knew something had gone horribly wrong.
It was February 1 2010 and Dr Sutcliffe had suffered a potentially-fatal haemorrhage.
His chances of survival were one in a thousand, and reducing with every passing minute.
Crawling to his phone, he managed to telephone Clare, his wife, and as he lay waiting for the emergency services to arrive he began drifting in and out of consciousness.
It would have been a unbefitting death for the first person ever to conquer each of the highest peaks on all seven continents at the first attempt, a feat he achieved in just four years.
Climbing since the age of 12, Alistair explained why he undertook the challenge.
He said: “When you stand on top of a mountain, it’s almost spiritual.
“You come down from these mountains with a little more that you can give and it makes me a better person at sea level.
“Another piece of the jigsaw puzzle that is Alistair Sutcliffe is complete.”
To attain this closeness to nature, there are huge risks and Alistair acknowledged that he saw a lot of death and dying in the mountains.
Throughout the challenges he’s had a number of close shaves, from being held hostage at gun point in Indonesia for 13 hours to coming just one safety hook away from tragedy in South America.
He was leading a climb up a sheer rock face on Aconcagua. As he approached the top of the climb, a safety clip popped out of the rock and the team of climbers fell, pulling the next four safety points out. One final clip held, preventing the climbers from falling thousands of feet to certain death.
“I asked everyone to cut their rucksacks off because the clip was wobbling and we needed to lose as much weight as possible. I could see the last one moving and if that popped out it would have been all over,” said Alistair.
“For some time I had that last safety point on my desk at the surgery so when people used to say ‘I had a really bad day Doc’, I would say ‘Let me tell you about a bad day’.”
It was for this reason that when he completed the final mountain ascent in 2009, Alistair chose to hang up his climbing gear.
In doing so he took advice from his childhood hero and friend, fellow mountaineer Chris Bonington, who wrote the foreword for The Hardest Climb. Alistair said: “The reason he’s alive and a lot of his friends aren’t is he knew when to stop.”
Indeed, three of the team who climbed alongside Alistair to the top of Everest have since passed away.
Yet, after surviving adventures on the edge of the world, death almost came in the bathtub at home.
“It was just about the worst pain you can imagine,” he said of the brain injury which struck without warning.
Following a haemorrhage, blood builds up on the brain, squashing it down onto the spinal column. Eventually it gets to the point where the receptors that control breathing stop working, and death follows.
There was nothing doctors could do, and Alistair found himself saying goodbye to his wife and his family.
He then quietly slipped into a coma.
Alistair said: “I remember being in a long tube. At one end of the tube was a big railway clock and whenever that clock chimed I would feel a lot of pain, so I spent a lot of time down the other end. The trouble was, the more time I spent down that end, it would be harder to get back up to the clock, to remind me I was still alive.”
Two days later he heard Clare’s voice at the end of the bed. He said: “I didn’t open my eyes because I didn’t want to be blind and never see her again.
“But I did, and I saw a shadow at the end of my bed. Then my sight returned and Clare will never know how beautiful she looked in that moment.”
He’d met his future wife when she was a medical student in 1993 and she helped him back from the brink. In the past she had encouraged his adventures, once even daring him to motorcycle to Timbuktu - which he then did.
But now, with the odds of leading a normal life after such a brain injury being in the tens of thousands, it was Claire’s job to help aid his recovery.
It emerged that Alistair had survived thanks to his mountain-climbing exploits. The excursions to high altitude, where there is less oxygen, had reopened his posterior foetal communicating artery, usually redundant in adults. This ensured oxygen reached his brain even when all the other blood vessels had become blocked.
Life has almost returned to normal for Alistair and although he no longer climbs, he regularly takes part in endurance running events.
However the haemorrhage has caused lasting side effects, such as chronic headaches and severe vomiting.
So, aged just 49, Alistair is reluctantly preparing to retire at the end of the year.
“Every day I look in the mirror and think You’re bloody lucky to be alive,” he said. “So I want to get the message out there to the patients, to say ‘Thank you’.”