Nathan Sexton is returning Sunday to the same starting line he toed a year ago when he ran his first half marathon to teach himself how to deal with prolonged pain amid a terminal cancer diagnosis.
This time, Sexton's motivation is his 3-year-old son, Jack, who has grown accustomed to watching his father compete ever since the 30-year-old ran into the local spotlight before last year's Chattanooga Marathon.
"He always says, 'I want to race just like daddy,'" Sexton wrote in an email. "He watches everything I do, and I just want to show him that anything is possible if your heart is in the right place and your intentions are good."
Sexton has outlasted the prognosis for his stage 4 glioblastoma, and he continues improving his running speed, almost two years after doctors discovered a mass in his brain and told him it carried an average life expectancy of 15 months.
The Signal Mountain husband, father and author is running so fast now he could compete for a top spot in Sunday's Erlanger-sponsored race.
Just five runners finished last year's full marathon in less than three hours. Sexton is taking aim at that category after spending the last few months training under local running guru Alan Outlaw, while continuing an experimental cancer treatment.
"Anything with a two in front of it would be amazing," Sexton wrote, adding that he hopes to qualify for the 2018 Boston Marathon, which he will do if he finishes Sunday's race in under 3:05.
"He definitely has a shot at the top 10, if not the top five," said Outlaw, owner of Fast Break Athletics on Cherokee Boulevard. "Depending on who shows up for the race, if he breaks three hours for the marathon, it could be anybody's game."
Sexton said he has run 1,543 miles since completing the 2016 half Chattanooga Marathon in 1:41:07. Soon after that race, his doctors recommended he stop chemotherapy and begin looking into clinical trials that might slow his tumor's growth.
He is participating in a phase 1 clinical trial at the University of Alabama at Birmingham that, so far, has kept the tumor stable. Sexton said he has not asked for, nor been given, an updated prognosis.
"My family and I are just trying to take things day by day and enjoy being in the moment together," he said.
So while Sexton has a goal time for the marathon and has been soaking up running knowledge "like a sponge," Outlaw said, Sunday's race is about more than just mile-splits, goal times and the chance at a top finish for him.
"The 'race' of life isn't about what place you come in, but as long as you give it 110%, you should be happy with your performance," Sexton wrote. "That's what I plan on doing this Sunday: giving it 110%, and being happy with whatever place I get. Love God, love others and make disciples, because that is what we are called to this Earth to do."
He knows, too, that reaching the finish line is not a foregone conclusion, despite his peak aerobic condition.
Sexton was forced to drop out of December's North Face Endurance Challenge 50-miler in California when, 6 miles after his first seizure, he had another one that drained his supply of medication.
He sought Outlaw's tutelage after returning to Chattanooga, and the two have been exercising together with an emphasis on heart-rate training. Sexton's ketogenic diet means he is fat-adapted and eats a limited amount of sugar and carbohydrates. Maintaining a lower heart-rate keeps his body working efficiently.
"We've trained him to the point to where he'll stay in a zone that's right there on the threshold where he can still run really fast and not use all of his glycogen storage since he doesn't have a whole lot of it," Outlaw said.
Outlaw, who turns 40 this year, recalled a moment from one of the duo's recent workouts that stuck with him. A hip issue was bothering the coach, and he verbalized his qualms with "getting old."
"Then I asked Nathan how he was feeling," Outlaw said. "And he said he was feeling great, like he always does."
A few minutes later, Outlaw grumbled about another physical ailment.
"And then Nathan said very matter of factly, 'Man, I'm just happy to be alive today,'" Outlaw recalled. "People say things like that all the time, but it definitely has a different meaning coming from him. It's been a blessing and a joy to be around someone with the kind of optimism and outlook that he has on life.
"It's precious to him."
Contact staff writer David Cobb at dcobb@timesfreepress.com or 423-757-6249.