The Routine: Bear Grylls, record-breaking conqueror of Everest

Edward 'Bear' Grylls, 27, in 1998 became the youngest Briton to climb Mount Everest. He trained for a year to achieve this feat, but before that spent 18 months recovering from breaking his back in a parachuting accident while with the British Special Forces, with whom he spent three years as a combat survival instructor and patrol medic. His next planned adventure is to travel from Boston to Edinburgh via the Arctic in a motorised rubber dinghy with Mick Crosthwaite, his companion on the successful Everest expedition.

How did you begin climbing?
Climbing has been my thing since I was a kid. My father taught me that I had to be crazy about something, and so I'm crazy about climbing. Everest has been my dream since I was eight years old.

How did you prepare for Everest?
I'm not a natural-born athlete and I hate the training, but I knew that to stand a chance of doing "x", I had to do "y". I was so driven by my dream. So many people were telling me that I was too young, that it was proven medically that my body could not cope up there.

How was the training structured in the run-up to the ascent?
We took a year out from the Army. The best training for climbing is climbing, so we spent a lot of time in the mountains, carrying heavy rucksacks for eight to nine hours a day, then going home to crash out for three days, just eating and sleeping. We would try to get to the hills about three times a week, either in the Brecon Beacons or in Scotland, but it was hard to have a regular routine, because at the same time we were trying to organise the logistics of the expedition.

How did you prepare your body to survive at high altitude?
Four months before Everest, I spent three months climbing other peaks in the Himalayas. Your body has a real memory of those conditions. There are hypoxic chambers in gyms that try to recreate the feeling of being without oxygen, and I also spent a lot of time swimming under water. It's all just scratching the surface, though. To be honest, there is no way you can really prepare apart from being there and getting your body used to it. You're there for three-and-a-half months, walking up to 17 hours a day; to be able to do this you need to have a reserve of energy and your body needs to have a memory of high altitude.

How do you develop this reserve?
By climbing and resting and looking after yourself. Classically, people arrive overweight, about half a stone, because they know they're going to speed through it. When you're in high altitudes your heart beats much faster: instead of being at 60, it's at about 110, because there is not enough oxygen.

Did you follow a particular diet?
No. While training I would eat absolutely anything. Up on the mountain we would eat dehydrated foods, trying to keep our nutrients up. Higher up the mountain your body can't digest anything because all the blood is going to your muscles. At that stage we would drink soups.

How does your body react to lack of oxygen?
You feel very weak. We would move about two paces a minute and then crouch down, holding our knees, hyperventilating. It's like having a pair of socks in your mouth and trying to run a 400-metre race hour after hour. You need to look out for the symptoms of altitude sickness: foaming at the mouth and gurgling sounds from your chest, which are a reaction of your body to the lack of oxygen. You basically end up drowning in your own blood.

How do you deal with altitude sickness?
Get down the mountain. We would let our bodies recover and then we would go back up again and push our bodies slowly. It is a lottery, because some people just physically can't cope. There are brilliant athletes who have tried to climb Everest but haven't succeeded. They might be great at sea level, but once you take out the factor of oxygen, things start going wrong.

What was the hardest part of training?
Getting up at five in the morning and squeezing in three hours of jogging. On so many cold January nights, when everyone was out clubbing, I had to run up dark hills. The people I trained and climbed with are really close friends, and that was the crux of everything up there. We were not just getting fit, but learning how we coped when we were tired, cold, frightened.

What was it like getting to the top?
All I could say was. "I want to go home." But it was beautiful. We got there at dawn and I saw the curvature of the Earth. Tears freeze before they hit the ground up there.

Tell me about your next project?
I definitely wanted to do something on sea level. It's called Expedition BT Bright Star, and I'm going to find a new route through the ice around the bottom of the Arctic Circle in a little inflatable boat with Mick, my climbing partner.

Have you had enough of climbing?
Climbing Everest made me nervous. I feel lucky to have come back, so I don't think I could do it again. I'm a lot less naïve now, although I still love climbing. I just don't want to die up a big mountain.

Interview by Manfreda Cavazza Bear Grylls will be attending the Adventure Travel and Sports Show today at Olympia, London. For tickets: 0115 912 9177 (£6 advance, £7 on the door). His autobiography, 'Facing Up', is published by Pan, £6.99