Sean Blanton will finish an 80-mile run Sunday morning. When he’s done with that leisurely stroll, he will cool down a short time later with 26.2 more miles in the Publix Georgia Marathon.

No, he’s not crazy. He is, as he is nicknamed, a “Run Bum.”

He runs because he can. He puts his mind and body through experiences that he guesses must be the pain equivalent of climbing Mt. Everest because he wants to make people ask what they are capable of.

He runs because he wants to aid cancer-research efforts.

He doesn’t have cancer. He has had family members who were killed by cancer, but it’s the possibility of helping, rather than the history of lives lost, that pushes him.

So Blanton, 26, planned to meet some friends at The Arch in Athens at 10 a.m. Saturday to do something that hundreds of college kids do every weekend when their laundry bags fill up or their stomachs get empty: head to Atlanta. Except he’s going to pound the pavement, pushing aside the probabilities of upset stomachs and nausea to the possibilities of renal failure and dehydration.

Upon arrival at Centennial Olympic Park, they hope to rest for as long as they can, possibly 1 1/2 hours, before they will run the marathon. The race begins at 7 a.m.

“I think this is a good cause,” he said. “For me not to use my running, what I do, to positively impact people, would be very selfish. If us running gets a dollar, a penny, whatever toward cancer research, I will go out and run 100 miles.”

Blanton grew up a determined kid in Druid Hills. His mother, Alicia, competed in some triathlons, but Blanton wasn’t interested. He was into the typical things: beanie babies and Cub Scouts when he was young; soccer, Boy Scouts and BMX as he grew up. He liked to go fast, but he was never into running. Running, he said, was stupid.

Four years ago, looking for a challenge, he entered The Atlanta Journal-Constitution Peachtree Road Race. He enjoyed the running, but hated constantly having to dodge people. his mom suggested he try other races. But he could never run faster because of the packs. So, he decided he would try races that were longer and had fewer people.

He already had a trip planned to New Zealand, so he signed up for a 17-mile mountain race.

He had no idea what he was in for.

His muscles seized. He hobbled the last few miles, crying as he crossed the finish line.

But it didn’t conquer him.

“It completely opened up my mind to what I could do,” he said.

And when Blanton commits to something, he commits. He didn’t just learn to ski; he skis double black-diamond trails, considered very difficult. He didn’t just learn Thai boxing; he went to Thailand and learned more.

“He’s an interesting kid,” his mom said.

When he returned to his hostel in New Zealand, he used the Internet to sign up for three more marathons.

Marathons became too easy. So Blanton turned to ultra-marathons, races longer than 26.2 miles.

Ultra-marathons turned into ways to help others because, as Alicia said, her son looks for the good in people.

“I’m hoping we can [make people think] ‘If these idiots can do this, then I can go run a 5K or a half-marathon. Maybe I can do something to raise money for cancer research,’” he said.

Blanton has run more than 5,000 miles. He competes in ultra-marathons every weekend. He has never been injured, though he usually is in pain. There have been races where he lay on the ground for six hours afterward, unable to move. Blanton said he avoids injuries by focusing on his form. Whether it’s the first mile or the 100th, he keeps his form constant.

Though the dangers to his health are numerous, from malnutrition to being hit by a car, his mom said she never worries about him anymore.

“I know that he’s figured out what it takes to deal with the challenges. He’s going to make it happen,” she said.

Perhaps the hardest part is the mental fatigue that could occur during this Athens-to-Atlanta-to-marathon test.

“I hit that wall in a marathon,” he said. “When you run longer than that, you hit several walls. All kinds of crazy stuff can happen.”

“All of a sudden you get sleep deprived, times you don’t know what’s going on. But if you stop and sleep, your muscles can lock up.”

He ran the route during an inline skating Athens-to-Atlanta event in 2009, another fundraising event for the American Cancer Society. He left 15 hours before the skaters and finished 10 minutes before the winner.

He and his friends planned to leave the Arch on Saturday and go southwest through Monroe before heading to Decatur. They will run on roads, which he said will likely cause them to travel 80 miles.

He said there wouldn’t be a police escort. His parents, friends and family planned to follow the group in a car with food and water. He figures he will consume between 8,000-12,000 calories as he goes.

Though they want to run at a leisurely pace, he hopes for a short break before the marathon starts at 7 a.m. He wants to finish that race in three hours, which is a solid target for anyone, much less someone who just ran most of the day and night.

This test of 100-plus miles is a warm-up for a bigger challenge: Blanton will run the Appalachian Trail, a distance of more than 2,000 miles, beginning in May. He said he will try to break the speed record by averaging 50 miles per day.

No, he and his friends aren’t crazy. They run because they can. They run because they want to inspire.

“We keep searching for something harder, longer,” he said. “That’s what ultra-marathons are about: pushing your body to the limit and walking that line between hurting yourself or coming through the gauntlet better for that. It’s the hardest thing you’ve ever done. So much time, pain and effort to get to the finish line. For us, that finish line might be further away.”