The health-conscious 77-year-old insists he has never been a fan of alcohol or drugs, and admits his addiction has always been the open road and a good pair of running shoes, reported Rolling Stone magazine.
"I've run about 105,000 miles... It's long-distance stuff - I mean, really long, all day, every day.
"I ran to all the missions in California, which is 914 miles. You do a mission a day and keep on going. You become a metronome... I've done all kinda crazy," Dern said.