Bear Grylls

Trial by fire, and trial by ice... Bear gives the lowdown on the second series of Born Survivor.

What's new in the second series of Born Survivor?

More extreme locations, tougher conditions: everything ranging from 130-degree heat in the Sahara to minus 40 in Siberia. Some of the most aggressive jungles and swamps in the world. It's me at my limit – I think the producer's always keen to up the ante, and make the locations and stuff I do bigger and better. I definitely do feel well out of all comfort zones, but I hope that makes good TV!

Having travelled to Siberia, the Panamanian swamps and the Sahara, which is the most inhospitable?

I think the extremes of temperatures are always hard. In the Sahara we had ridiculous heats where three of our crew had to be evacuated with heat stroke. And then in Siberia I had to swim under the ice of a frozen lake. I was standing there before diving into a big hole – with no clothes on – but my feet had actually frozen to the ice. I just thought: 'this can't be good for you'.

But I also kind of thrive on that. There's no room to get things wrong in those conditions. In more temperate places you can always get away with a few mistakes, but in those sorts of temperatures you can't. It's definitely where it's toughest to film. I enjoy really having to raise my game. We've got a brilliant crew of people who come with me and I really love to see how they cope and help them through stuff.

Diving into a frozen lake naked sounds pretty terrifying, but which is worse, the ice or the Sahara?

They're both mad, they're both very unforgiving: that's the bottom line. That's why I love being at home: I don't get bitten by any crocodiles, I don't get bitten by snakes, I'm not roasting my arse off or freezing my nuts off! But extreme heat and cold are both hard. Cold for me is particularly tricky because I've got some damage from frostnip from previous climbing expeditions. It means I really have to fight to keep the circulation in my toes and fingers now, and I had quite a struggle in Siberia with that a lot of the time.