SINCE I’VE taken up adrenaline sports, my holidays tend to be extreme as well. Within a few hours of climbing

El Capitan, a 3,000ft vertical rock face, I was with my parents in a luxury hotel, lounging in a hot tub and eating dinners that replaced a lot of the pounds I’d lost on the climb. My life is a bit like that now: one minute in a tent in the desert, the next drinking tea in the Dorchester.

I started climbing for a television show and am totally addicted. I have an addictive personality, and needed a fix other than sex, drugs and alcohol. Climbing is that fix. Before sobering up, I was totally dismissive of it; but, post-rehab, the idea of being out in the wild, living by your wits, really appealed. My first climb was in Slovenia, and I immediately fell in love with it. It seemed the coolest thing ever that you could get up this rock face using nothing but your hands, ropes and skill — like a high I had never experienced.

I’ve just come back from 10 days in Yosemite Valley, in California’s Sierra Nevada mountains, with a couple of friends. You’re physically active, but it’s still a relaxing break — you’re so focused on what you’re doing that there’s no time to worry about anything else. We’d be up by 9am, climb or hike all day, then maybe jump in the river for a quick rinse before cooking dinner on a stove back at the camp site. When I’m in the mountains, I’m just Jack, and people respect me for my climbing ability rather than being Jack Osbourne, one of the Osbournes. I love it.

Two years ago, I went to Croatia to do deep-water soloing: climbing sea cliffs with no ropes. We’d pull up to the cliffs in large yachts, climb, then fall 40ft into the ocean. It was pretty scary, but okay as long as you entered the water with a straight body — otherwise you risked an impromptu enema.

My best and worst holidays have been to Hawaii, where my parents go with depressing regularity. They married there in 1982, and can’t resist the romantic gesture of returning as often as possible. Dad is a creature of habit and, when planning family holidays, you could write the script before the conversation started. It always ended with him saying, “I don’t wanna go anywhere. Let’s go to Hawaii.” It’s amazing, but after 40 times, you start viewing grass skirts and floral garlands with a certain weariness — and if you’re not a heavy drinker or a three-year-old, it all gets pretty monotonous.

There were also a few family ski trips. Mum and dad are no skiers, but my half-brother and half-sister are heavily into it, so we went to Zermatt, where I was so ill, I was hospitalised. These days, I love snowboarding and the more extreme version, heli-boarding: you’re dropped on top of a back-country mountain to make your way down — unless you get hit by an avalanche. In Utah, it was totally wonderful, in remote mountains, boarding on 4ft of untouched powder snow.

Filming Adrenaline Junkie let me do some pretty amazing things in incredible places, such as kick boxing in Thailand and jungle trekking in Belize. It was hot and wet, but, in hindsight, incredible. We saw the world’s third-largest cave system and literally tripped over old Mayan ruins in the jungle. Having to sweat to see things makes them all the more impressive.

I also bungee-jumped in South Africa, which wasn’t the best experience. I was nervous, but once you make yourself do it, there’s not really anything to it. The biggest frustration was that we simply flew in to film, then out again. My experience of the country was plane, car, hotel, jump off bridge, car, plane and out. I’d like to have seen Johannesburg and Cape Town, and climbed in the Drakensberg Mountains. I definitely want to go back.

Probably the worst thing I did was running with the bulls in Pamplona. People have died or been seriously injured — some by the bulls and others by people running away from them. What makes it harder is the tradition of drinking the night before: the ground is slippy with vomit and booze. I got a real high from taking part, but found the town and drinking really depressing. There were so many drunken 14-year-olds, and I guess they reminded me of my former self. I couldn’t wait to get away.