The really momentous stuff in life is not merely fun. And that is where the appeal of challenging myself comes in. It’s how I forge who I am and who I want to be. The reward is the sense of achievement and surprise.

Each time I succeed at something I thought would be difficult I expand my boundaries a fraction. I am pleased to have succeeded. I want that feeling again. I set another challenge. But the next one needs to be a little more difficult. It’s a circle familiar to all addicts: to get the same buzz I have to take a bit more, or try something a little stronger.

Accompanying striving for achievement and relishing suffering is the element of proving. I take on challenges primarily to prove myself to myself. There is also an element of proving myself to other people, either to win their praise, or as a metaphorical two-fingers. It is not the most noble of motives, though it is certainly effective. But in the long term I find it less powerful than the pride I feel within myself.

In my study there are no photographs or mementoes of my journeys. The memories are not very important to me. I don’t buy souvenirs. It is the thought of the next challenge that fires me, not reflecting on past glories.

This text is an extract from There Are Other Rivers, available as a giant mappazine or a free Kindle sample.