Bishop Leatherbury sounds like a normal, intelligent person.

He’s 59. He lives in Sandy Springs. He’s a managing partner in a professional services firm. He’s active in charity work.

But this normal, thoughtfully spoken man has a bucket list, a short catalog of things he wants to do while he still can. It has unhinged him a bit.

On Saturday, he will compete in Hawaii in the Ironman World Championship triathlon, a 140.6-mile, 8,500-calorie, jelly-leg-causing test of physical and mental strength and endurance that many people watch, but few have the guts to try. Imagine traveling from Atlanta to Athens and back again by swimming, biking and running.

“When I tell people I’m doing the Ironman I’ll get three reactions: The people that know about Ironman are like ‘Wow, how did you get in there?’

“Other people can’t really believe that somebody would put their body through that.

“Others are like ‘Oh, OK,’ because they don’t understand the level of commitment.”

It’s not for the weekend warrior.

The event starts with a 2.4-mile swim in Kailua Bay, followed by a 112-mile bike ride up a mountain, and ends with a 26.2-mile marathon.

This will be Leatherbury’s sixth full Ironman triathlon. He also has completed 20 marathons, 17 half-Ironmans, three Olympic-distance triathlons (one-fourth the total miles) and one sprint triathlon (anything less than an Olympic distance).

There are different ways to qualify. Leatherbury made it by winning the entrants lottery, one of 200 slots set aside in the annual event.

Leatherbury has been training since March. At the height of his training, he will put in 20-22 hours a week, which includes 175 miles of cycling, 30 running and 4-5 miles of swimming. He says it’s a lifestyle.

He has trained that hard because he said he wants to be an official finisher. To do that, he must finish the race within 17 hours. The event starts at 7 a.m. and ends at midnight. His previous Ironman finishes range between 13 hours, 42 minutes and 14:03.

“I would be ecstatic if I can complete this in under 14 hours,” he said.

While all the portions are difficult, he said swimming is the toughest for him and one of the reasons he once avoided competing in triathlons. He has always been a runner. However, he suffered a stress fracture in one of his legs that forced him to the pool. After a while, he realized that he could at least enter and see what would happen.

He competed in his first triathlon in 2000.

He thought about entering an Ironman race after watching Dick and Rick Hoyt compete in Hawaii on TV. The father-and-son team are famous because Rick has cerebral palsy. His dad pushes him during the races.

“That was a real inspiration,” Leatherbury said. “If that guy can push his son 140.6 miles, that would really be something to do.”

Leatherbury entered his first Ironman in 2005. He soon began entering the annual lottery to compete in the Hawaii Ironman, known as the Super Bowl of triathlons.

After the race, he and his wife will vacation in Hawaii until Wednesday before they return home, where he will take a month off training to recover.

He will then start planning on the other things on his bucket list: running the Boston Marathon and hiking to Machu Picchu, an ancient Incan site in Peru.

He has no plans to stop entering Ironmans. He said he will enter the lottery again to make it back to Hawaii.

“I think my family thinks I’m crazy,” he said.