Veteran movie star Bruce Dern is such an avid runner he believes he has jogged the equivalent of 300 marathons in his life.

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.

The Monster star tells 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 running s**t."