Mountaineers form very close bonds. If you survive an epic with a friend, you stay close forever. I once climbed the Welsh 3000ers at one go in winter. These are the 15 or so 3000-ft peaks in North Wales that constitutes one of the great walks/climbs in the UK. After 36 hours continuous climbing in freezing conditions, I felt the blissful need to stop and sleep awhile, a classic sign of hypothermia which leads to death. My companion, a geographer who later became a professional map maker, calmly persuaded me to continue and through some amazingly accurate compass work in thick fog led us to safety. This was 35 years ago, but I do not forget that I owe him my life.

For all their closeness, mountaineers are also people who crave solitude. I trekked and climbed for a month in West Nepal in 1972 accompanied by two Sherpas and four Tibetan porters. We took two weeks to reach a high pass called the Jangla Bangjan and then two more weeks to regain civilization through a series of high passes (around 17,000 feet each) that nobody had crossed for decades. On the last day before reaching the road head, I saw in the distance a Westerner walking towards me. In a panic, I left the path climbing rapidly to avoid meeting him.

The exertion in mountaineering is mental as well as physical. I did my first Alpine routes when I was 12, en famille and guided. Our venerable guide led the way out of the village up to the mountain hut so slowly I could hardly pace myself correctly. But he never stopped and we reached the hut and the following day the summit with complete ease. With a steady walk, the climber quickly slips into a state of meditation, with the rhythm of his steps defining some personal mantra. For me, it is a piece of music. Either way, the ascent drops away as though it is nothing.

Sometimes the mental activity becomes a game to survive. After two nights sleeping at 7700 m on Cho Oyu, one of the world’s 14 peaks over 8000 m high, and then collapsing at 7900m during a summit attempt, I began a descent that was a nightmare of stumbles and falls. Having reached within 20 meters of our tents in camp 1 at 6000 m, I should have felt some relief. But there was a small incline with 50 or so remaining steps. As other members of the expedition blankly followed my progress, themselves too tired to offer encouragement, I drew up a crazy scheme whereby each step corresponded to a famous church or chapel. If fine craftsman could build this church, I said to myself, so I could take the next step! The fifty steps consumed fifty churches.