“A lot of people run to see who’s fastest,” said American distance runner Steve Prefontaine, “I run to see who has the most guts.” It’s a stirring quote, but it doesn’t help explain why some people have more “guts” than others. Why do some admit defeat as soon as the going gets tough, while others rise to adversity as though they had been waiting for the fight?

Late last year, I was lucky enough to learn about someone who, for me, epitomises the latter group. His name is Dave Heeley…