09/09/2013 10:50 BST | Updated 08/11/2013 05:12 GMT

Part 2 - Risk

Someone's attitude to risk is an inherently personal relationship. Take ten people together and their risk thresholds will be vastly different. Many people go through life confined securely within a small comfort zone, avoiding stepping out to venture into the unknown at all costs. Others fly through life on a roller coaster, reveling in risk taking in all manner of ways.

Is there some hidden factor determining our attitude to risk? Some people mistakenly assume or tell me that I'm an adrenaline junkie but, while some daredevils and their activities fall into that category, I can personally vouch that there is nothing remotely adrenaline producing in pulling a 130kg sled in brutal weather for 50 days and 800 miles over a polar ice cap, always cold, hungry and chronically tired.

Science may indeed provide some clues, but it is dopamine not adrenaline that is the culprit. Dopamine is a neuro-transmitter; the brain's feel good chemical reward system, responsible for the high we receive when we achieve or experience something good and the level of drive, ambition and risk taking behavior we exhibit.

A number of recent studies, most notably from researchers at Vanderbilt University Nashville and the Albert Einstein College of Medicine in New York, have shown that risk takers' brains appear to have fewer dopamine inhibiting receptors, the controllers that regulate the amount of dopamine produced. The result is their brains are more saturated with the chemical, prompting them to continue taking risks to seek the next high. According to their findings, those who lack dopamine conversely experience procrastination, lethargy, depression and other mental ailments.

But what happens when these dopamine induced individuals take risks and fail? In business, the penalties may be a dramatic loss in profits, shareholder value or, at its worse, the company itself. In adventure and exploration, the cost may be one's life.

High altitude mountaineering is probably unique in the world as being the only sport or pastime where death is a constant risk, continually faced and often talked about. An outsider observing a group of mountaineers together would probably be shocked at how frequently death is mentioned - sooner or later the conversation will turn to someone known dying of cerebral edema on a Himalayan giant, followed by someone else being killed by a fall on the south face of another. It all appears very casual, matter of fact and lacking any empathy.

But the insinuation that climbers are flippant about life and death is false. Most climbers will say they climb to feel alive. And I believe my experiences - and the vast majority of climbers I know - lead me to value life and treasure each day far greater than many who go through life failing to appreciate the present and forever wishing their lives away for each Christmas, the next holiday or retirement.

And the shocked reaction and upset of climbers in Pakistan to the execution by the Taliban of 10 foreign climbers and a Pakistani cook at Nanga Parbat base camp on June 22nd showed that even supposed hard core, death defying, risk takers have emotions and are human. Which also brings home the paradox that, while it's an accepted risk of the sport to die from avalanches, falls or altitude, to be killed in a cold blooded mass execution by 16 murderers isn't. However, although approximately 75% of trekkers cancelled their tours following the incident - crippling the struggling Pakistani tourism industry - every climber carried on their planned ascents of Karakorum peaks without hesitation. Climbers face and deal with risk constantly and tend to evaluate it with a far more evolved, logical and less emotional attitude than most people. And the simple fact was that most faced far greater risks on their respective mountains than by the remote possibility of a similar terrorist attack happening again.

The reward for taking these risks is what drives ever more mountaineers, adventurers and explorers to further expand their limits and seek new challenges. A connection with nature and with one's body that is impossible to find in other walks of life; where one escapes our material and information overloaded world for a place where nothing else matters apart from your willpower, your breathing and your next move. And, when reaching the top of a mountain or the end of an ice cap, the most incredible sense of achievement and accomplishment.