The air is cold up here; so sharp and thin it feels brittle. It tugs at your jacket and there is something unnerving in the way that it challenges your breath, making the natural motion of breathing a more deliberate act. Above you the sky is clear; there is nothing. Below you: the world. It’s hard to look down without feeling drawn over the edge, but you know it’s there, somewhere below the clouds, because you kicked a stone and after a few seconds of silence you heard it crack and clatter three times before the echoes stopped. As the mist burns off, the hard, craggy 
valleys below come into focus and the sheer scale of the cliff bleeds terror into your bones.

Andy de Klerk has been on that edge more times than he cares to count. He chooses – or rather, he is driven – to be there, teetering on the brink of what some might call insanity. But he is not reckless or an attention-seeker; De Klerk climbs mountains because it makes him feel alive, not because it has the potential to bring him face-to-face with possible death. He is a calm, focused man who simply feels compelled to push the boundaries when it comes to mountains.

“I read Heinrich Harrer’s book The White Spider  about the first ascent of the Eiger when I was 10 years old, and I knew then that I was going to be a climber,” he says. Now at age 45, De Klerk’s name is known around the world; he is an accomplished rock climber, respected for opening many routes on some of the planet’s most challenging mountains. His adventures include “getting fried by lightning on Mount Alberta in the Canadian Rockies, and nearly getting taken out by a large rock fall in the Alps while soloing the Dru.” He’s also battled loose rock in the Sierras, 
survived brutal cold and injury in Alaska, and taken on huge unclimbed peaks in the Himalayas.

De Klerk’s vertical adventures don’t stop at going up, however. He base jumps too, leaping off mountains with a parachute on his back – and in the few minutes before he launches himself off terra firma, he feels pure terror, and an intense struggle to keep that terror under control. “Your instinct is screaming at you saying ‘don’t jump’ and another part of you is saying ‘relax – everything is going to be fine’. That inner turmoil is completely hidden under the cloak of calmness.”
“You throw a rock into the mist, setting a challenge for yourself. You don’t know if you can do it. The cards are not rigged; you put yourself into a place that only you can get yourself out of. This is adventure in the true sense of the word.”

The Chemical Factor

What is it that has one person placing their life at risk by plummeting off the edge of a mountain in search of adventure, while most others shrivel in fear at the mere thought? Why are some people drawn to this level of adventure – spending most of their lives taking huge risks and dreaming up crazy ideas about tight-rope walking across canyons or kayaking over waterfalls – while others choose to get their thrills from, say, mountain-biking a new trail on a Sunday morning? While the answer boils down to a fine balance between your desire to seek new sensations, your level 
of fear and how impulsive you are, the answer can be summarised into one word: dopamine.

“Sensation seekers have been described as having a Type-T 
personality,” says Johannesburg-based clinical psychologist Jaydon Immerman, referring to the extent to which people seek 
stimulation, excitement, sensation, thrills, arousal and adrenalin. And Type-Ts’ bodies, he says, have a lower level and a different way of processing dopamine.

Dopamine is the chemical responsible for us taking risks; 
it’s also responsible for making 
us seek out new experiences, and learning new things. Dopamine is the neurotransmitter (a chemical messenger that carries signals between neurons and other cells) that’s commonly associated with the reward system of the brain. 
In other words, it makes you feel good once you’ve achieved something. More accurately, says 
Professor Russell Poldrack, neuroscientist at the University of Texas, dopamine is a motivating signal; it is what makes you prepare to take the action that will bring the reward.

We don’t all have the same 
levels of dopamine, which is why we aren’t all ordering custom-made wingsuits, practising Eskimo rolls or making plans to get to the Himalayas. It’s people with lower levels of dopamine who tend to take bigger risks.
For years the thinking was that it was only dopamine levels that determined if someone was likely to be a thrill-seeker – but a 2008 study published in The Journal of Neuroscience revealed something else. Researchers at Vanderbilt University in Nashville, Tennessee, used brain-imaging techniques to look at the levels of dopamine receptors in people’s brains, and they discovered that thrill-seekers may in fact process dopamine in a different way to 
the average Joe. The cells that produce dopamine have inbuilt “autoreceptors” that act as the fun police by cutting down the production of dopamine when the levels rise; thrill-seekers have fewer of these autoreceptors, which means that they need a greater amount of stimulation 
– a bigger thrill – in order to feel the same amount of stimulation the average person would. And so these people seek out bigger, 
crazier adventures.

“We’ve found that the density of these dopamine autoreceptors is inversely related to an individual’s interest in and desire for novel experiences,” said Dr David Zald, who led the study. In other words: the brains of people who take crazy risks might not regulate dopamine as effectively as the average person; and so they’re driven to seek higher stimulation in order to feel the euphoria.

Danger: Men at Work

Have you noticed that there’s been no mention of adrenaline yet? That’s because people like 
De Klerk – adventurers who spend months planning a climb, an expedition, the first descent 
of a river – are not “adrenaline junkies”. They’re stimulated by the dopamine that fires in their brain, not by an intense rush of adrenaline.

Like dopamine, adrenaline is a neurotransmitter – but its function is in fact opposite to dopamine. Dopamine is what motivates you to face possible danger in order to achieve an outcome, while adrenaline is responsible for helping you escape that danger. Adrenaline kicks in when you realise you’re facing a risk: it sends your body into fight-or-flight mode by increasing your heart rate, raising your blood pressure and giving you that intense burst of energy you need to get out of danger.
“Danger is relative,” De Klerk points out. “If you do something every day at the highest level, it does not feel dangerous. It feels normal.” Think about it – the first time you surfed a four-foot wave or rode a technical singletrack, you might have been daunted, scared perhaps. But the more you did it, the easier and more normal it became. “For me, danger is not a motivator, nor is it inspiration,” he explains. “It is simply something that is there on the sidelines of my passion, something to be set aside while I challenge myself.”

The self-challenge is one of the main motivators for people who seek out adventure. It’s a personality thing, and some people love to challenge themselves while others, says Johannesburg-based sports psychologist Greyling 
Viljoen, have no real need to do so. People like De Klerk often spend their lives challenging themselves mentally and physically, but 
that doesn’t mean that they’re addicted to adventure, or to taking risks. It’s the feeling of reward that they crave.
“People can get addicted in a positive way to the feeling that accompanies risk, and that feeling is a physical and emotional reaction triggered by the activity,” explains Viljoen. “Adventure-seekers can therefore crave the feeling associated with risk taking. It is the feeling they want and not the actual risk.”

Once De Klerk’s base jump is over or he’s scaled a sheer cliff face and he’s back on horizontal ground, the sense of achievement, the natural high, doesn’t last for very long. “That euphoria is fleeting. There is just emptiness and a vague depression afterwards,” he admits. “If you give everything towards a goal and then you reach it, there is nothing left except sadness because you’ve reached the goal; it has now ended and it takes time to think up a new one to replace what you have lost.”

Learn from Your Experiences

The science of adventure doesn’t end there. It turns out that exploring shapes your brain, and that being adventurous helps to shape your personality – and research into this is helping neuroscientists develop new methods for treating psychiatric diseases (but that’s another story entirely).

Earlier this year, researchers from the German Centre for 
Neurodegenerative Diseases 
published a study in the journal Science; they’d been observing genetically engineered mice, and wanted to see why, when they’ve been raised in the same environment, identical twins are not entirely the same. Forty of the 
little guys – all genetically identical and fitted with microchips – spent three months living in the same elaborately fitted multi-storey cage. “This environment was so rich that each mouse gathered its own individual experiences in it,” said Professor Gerd Kempermann of the German Centre for Neurodegenerative Diseases – 
and by the end of the experiment the mice had developed different personalities. The researchers also found that the brains of the more adventurous mice were building more neurons in the hippocampus (Grand Central for your brain’s learning and memory) than those who preferred to sit on the couch, so to speak. The study shows that it’s not only genetics or only the environment that form your personality; the experiences that you have and how you respond to them contribute, too.

It’s an Evolutionary Thing

Whether you’re a thrill seeker or not, we are all cut out to indulge in some level of adventurous behaviour. Scientists at The University College London’s Wellcome Trust Centre for Neuroimaging have discovered an area of the brain that is activated when you choose unfamiliar options – and that encourages you to move out of your comfort zone.

The 2008 study, which was published in the online journal Neuron, found that when volunteers were faced with two options and they chose the unfamiliar one, activity increased in the ventral striatum, an area of the brain scientists say is one of the “evolutionarily primitive” regions of the brain. Why is this important? Because it suggests that the process of taking a chance, or seeking adventure, could be beneficial to our evolution.

“Seeking new and unfamiliar experiences is a fundamental behavioural tendency in humans and animals,” says lead researcher Dr Bianca Wittmann. “It makes sense to try new options as they may prove advantageous in the long run.”

Basically, we become better humans when we try new things, and our body ensures that we 
continue with this evolution by rewarding us with mood-boosting chemicals, including dopamine, when the risk we take has a positive outcome.

When You Become 
Mr Sensible
As a kid you climbed trees you now consider too high; as a teen you skateboarded on ramps you now think are too steep; and when you bought your first car, you drove it far too fast. What’s changed?

“Kids have a greater ability to live in the moment and not be so aware of consequences,” says Greyling Viljoen, a sports psychologist from Joburg. “There is even new evidence that neurologically we only develop the capacity to act fully responsible in early adulthood. Children would therefore be more willing to take part in activities without being too aware of the possible negative outcomes. Most adults progressively become more aware of responsibilities as they get older.”

Dopamine also comes into play – again. Our bodies contain enzymes called monoamine oxidase (MAO), which are involved in the regulation of the dopamine neurotransmitter. Thrill-seekers 
naturally have a lower level of MAO in their bodies, explains Immerman, but for all of us, the level increases as we get older. 
So whether you get your thrills from jumping off mountains or driving fast cars, it’s likely that 
the older you get, the less you crave the sensation you get from those activities. But dopamine and MAO aren’t only to blame 
for your increasingly sensible ways: people generally start to settle down from their mid-
twenties and so naturally lose some interest in risk taking and adventure seeking, Immerman points out.

Looking back at what he’s 
done – including summiting 
many of the world’s most challenging peaks, and often doing it solo – De Klerk says that there are 
“so many seemingly crazy things 
I did that didn’t seem crazy at the time,” and he is, he admits, very glad to still be alive. Over the years, his sense of adventure has changed and his passion has now been replaced by joy. “I don’t have to prove myself anymore because 
I have seen what life really is, and it is a beautiful, special thing.”

“I love to be high up off the ground, totally in control. That could be when I’m climbing, 
skydiving, base jumping, paragliding or just going for a walk in the hills,” De Klerk says. “I love looking down on the world, so small and far below it just puts everything into perspective.” Being high – physically high – is what makes De Klerk feel most alive.

– Narina Exelby