Constantinos “Dean” Karnazes has been closely tied to ultra-marathon running for more than two decades. His life and career outside the sport are closely tied to what he has achieved within it – as well as being popular speaker and businessman in his own right, he is also the author of six books, the latest is A Runner’s High came out in July.

The book’s tag” Older, Wiser, Slower, Stronger” covers Mr Karnazes, now in his early 50s, preparations for taking part in the gruelling Western States 100 Mile Endurance Run in Californian Sierra Nevada Mountains. It was a race that he first ran 25 years before when he was in his physical prime. The last time he had run it, in 2009, he did not finish and that rankled with the author.

Completing that first run of the Western States was to transform his outlook that this loneliest of sports was what he wanted to do for the rest of his life.

He decided he would dedicate his life to ultra-marathon running and he built a life career path where none had existed before.

In the years that followed, Mr Karnazes gained international recognition with Time magazine listing him among its top 100 influential people in the world. He has clocked over 100,000km in runs that have taken him around the world. Memories of those runs do feature in the book, including a run along the Silk Route through Kyrgyzstan, Kazakhstan, Uzbekistan that was arranged by the US government as part of a diplomatic initiative in Central Asia.

READ MORE: A chance to ‘run’ with ultra-marathon legend Dean Karnazes in Australia

A Runner’s High is a meditation on life by an older, wiser athlete. It is also a meditation on how his passion has affected his family. Julie, his wife, has known from an early age that she wanted to become a dentist and runs a successful dental practice in San Francisco. While she has been accepting of her husband’s dedication to ultra-distance running and all the sacrifices it has required, she is also focussed on her life and that of their two children, Nick and Alexandria.

While the children have taken to running it is not to their father’s level of dedication. There is the concern playing in Mr Karnazes as to how good a father he has been and it is something that will play in his mind as he faces the psychological challenges that are as much an obstacle to the lone runner as the terrain in which he runs.

But his family is there for him. His father, Nick, is at the checkpoints to give him food and boost his morale in the Bishop High Sierra Ultramarathon in the California desert that Mr Karnazes needs as part of his preparations for the Western States. His father has backed him up for most of his running life.

Nick and mother, Fran, are there for him again when he does eventually get to run the Western States. The final send-off before Mr Karnazes goes to the starting line is their traditional preparation: a dance to Mikis Theodorakis’ Zorba’s Dance in their camper.

Playing on the runner’s mind once the race gets going is whether his son, Nick, will show up as promised and have everything ready for him as he needs in the later stages of the run. The planning had not been reassuring with the son assuring his worried father that he had helped before and knew exactly what needed to be done. No further discussion possible

For all his worries, Nick shines through and helps his father to overcome pain and growing doubt that he can finish the gruelling race.

Ultimately, it is this connection to family that makes the books something more than reflections on a challenging sport.

The book is also a study of an athlete who may past his athletic prime but who is still in tune with the sport that has defined much of his life:

In the book Mr Karnazes asks: “How to remain relevant in the face of Father Time? And from a practical standpoint, how to continue paying the bills and making a living from running? I’d given myself up to this sport, gone all in. That was my nature. …. If I failed at making a living through running, there were only darkness and destitution. … The simple act of running is what I loved most, and I was wholly committed to remaining faithful to my true self. Anything else would be a compromise, a sin. In my soul, I was a runner, and if I were anything else my life would never be fully lived.”

A Runner’s High achieves that and then some.

♦ A Runner’s High is published by Allen and Unwin.