To get ready to climb Everest, I did a lot of hill running with a daypack on and a lot of underwater swimming. I would swim a couple of lengths underwater and then a couple above. It gets your body going with limited oxygen.

The appeal of the wild for me is its unpredictability. You have to develop an awareness, react fast, be resourceful and come up with a plan and act on it.

Unless you have shelter, fire is going to be very hard and if you have fire, but no water, you're going to die. They're all super important.

When I'm in 'Man vs. Wild' mode, it's not pleasure. Every sensor is firing and I'm on reserve power all the time and I'm digging deep - and that's the magic of it as well, and that's raw and it's great.

I come from a line of self-motivated, determined folk - not grand, not high society, but no-nonsense, family-minded go-getters.

Exercise helps my back. If I don't exercise, that's when it starts to hurt. The pain is a good motivator to run and exercise.

I think fire is so critical in the wild. You can cook with it, you can make tools, you can deter a predator, you can dry your clothes and you get that element of morale that matters so much when you're stuck in the middle of nowhere.