Over the past 30 years, his extreme endurance events have taken him around the world. He conquered the world’s seven tallest summits — including Mt. Everest — on his first try. He has competed in more than 100 races, averaging more than 125 miles each.

And at the age of 57, he smashed records with his coast-to-coast run across the United States. For 52 days straight, he averaged 100 kilometers a day, the equivalent of two marathons and a 10K every day!

Marshall says he started running when he was consumed with grief. His wife was diagnosed with cancer at 28 and died at 30. He said he had a lot of trouble picking up the pieces of his life.

Then he discovered running and its healing effects on his mind and body. The road was the only place he could find any peace.

Today, Marshall admits his children suffered from his dedication to the sport.

He writes about this and his extreme endurance events in his new book, “Running on Empty: An Ultramarathoner’s Story of Love, Loss and a Record-Setting Run Across America.”

Marshall says he wants his book to show people, whether they run or not, that we all are capable of so much more than we even imagined, especially later in life.

As he approaches 60 himself, he explains how running is a metaphor for learning to push past the limits in your mind.

And he believes running can help you stay younger mentally and physically as you age.

Plus, find out why Marshall has raised more than $1 million with his endurance runs and which group of people he’s dedicated to helping.

To learn more about Marshall’s book and to see photos of his adventures, click here to visit his website.