POCATELLO — Aging doesn’t mean slowing down according to local athlete Sam Krieg. The 39-year-old raced in the 120th annual Boston Marathon April 18 and finished 48th out of nearly 30,000 runners.

Krieg ran for the first time on a whim 20 years ago for the marathon’s 100th anniversary. He was 19 at the time and guessed that he finished somewhere near 15,000th place.

This year, Krieg finished with a time of 2 hours and 33 minutes — an hour faster than his time 20 years ago.

“It’s about a 5 minute and 45 second mile,” said Krieg. “So I was just able to string together a bunch of five-minute miles. Which is cool, it’s about 11 miles per hour which is a pretty solid clip if you think about running on a treadmill at 11 or driving in your car.”

Despite his recent success, and the fact that he’s run nearly a half dozen marathons, Krieg said he doesn’t really consider himself a runner. His athletic background is in climbing, kayaking, bike racing and skiing.

“Since I’m almost 40 now, racing my bike isn’t quite as appealing,” said Krieg. “Running seemed like a natural way to use this endurance I’ve built up.”

Unlike his last Boston Marathon, Krieg said he put in about six months of training for this year’s race. However, he said Idaho winters aren’t really conducive to fast marathon training.

“I Nordic ski race, so that’s a lot of what I did this winter,” said Krieg. “I also spent a little more time than I’d like to admit running on a treadmill indoors just trying to get a fast marathon pace.”

The Boston Marathon does require racers to qualify, and Krieg said he really liked the competitive aspect that seemed to bring to the race. He also said the marathon distance itself makes racing interesting.

“At about 1,500 calories, the human body starts to get into trouble,” said Krieg. “That hits around mile 20, but at mile 20 you still have 6.2 miles to go in a marathon.”

It’s what runners refer to as “the wall.” The Boston Marathon has the added bonus of a hill right around mile 20 known as “heartbreak hill.”

“You have to run those last six miles off a little bit of passion and a little bit of guts,” said Krieg. “You know you’re going to have a crash landing, but you just don’t know how bad. At that point, it’s just damage control.”

Despite all that, Krieg said he’s got plans to continue running marathons. He hopes to find a slightly flatter course — possibly Chicago or Berlin — to try and break 2 hours and 30 minutes.

“It just seems like a good barrier,” said Krieg.

He said he also wouldn’t rule out heading back to Boston in another 20 years.

“It’s been a novel experiment,” said Krieg. “There’s something exciting in the back of my head about the 140th Boston Marathon. Just to see how fast I could be at 60 or 80. Just stepping up to the starting line in 2056 before my 80th birthday would be something.”

Krieg has lived in Pocatello since 2004. He runs a sewing company that makes bags for bikers and climbers, and his wife, Karen, is a professor at Idaho State University.