When Jacque Tellei needs a break or an energy boost, she goes running. Her three children, ages 9, 12 and 14, understand this.

"They understand mom is not happy if mom doesn’t run," said Tellei.

Of course, a run for Tellei typically means an hour and a half on the trails at Tantalus, not just a jog around her Manoa neighborhood. If she’s strapped for time, she goes for what she considers a short run — 6 miles.

Tellei, 42, belongs to the Hawaii Ultra Running Team, a group of long-distance trail runners whose goal is to finish the team’s annual H.U.R.T. 100-Mile Endurance Run every January. Tellei entered once, in 2014, and finished a staggering 35 hours and 40 minutes later. It was a milestone in her life. At the finish, she rang a bell, according to tradition, and organizers gave her a belt buckle.

"I just started crying because I was so overwhelmed," she said.

Running is second nature for Tellei, who grew up playing in the mountains and oceans of Palau before moving here to study at the University of Hawaii at Manoa. When she was a child in Palau, it was not unusual for her to wake at 4 a.m. to walk for hours along foot paths to visit a neighboring village.

But Tellei did not become a serious runner until after the birth of her first child. A stay-at-home mom at the time, she would put the baby in a stroller and run around Diamond Head. She did the same with a double stroller when her second and third children were born.

She ran the Honolulu Marathon in 2003 to check it off her bucket list. She liked running marathons so much, though, that she ran others.

What Tellei particularly loves about trail running is the opportunity to be out in nature, which she considers nourishing.

"It’s meditative," she said. "You don’t hear cars, you hear birds. Every inch of this mountain is different. It brings me back to earth. It’s humbling, it’s grounding."

Tellei’s introduction to the 100-mile race came when she volunteered at an aid station in Nuuanu during a race five years ago. She had been sidelined from marathon running by iliotibial band syndrome, a common and painful overuse injury that affects the leg.

She recalls thinking: "These people are nuts. I would never do this."

The very next week she was invited to run 20 miles on Tantalus with a H.U.R.T. runner, and got hooked. It was about six hours of running trails from the Hawai‘i Nature Center in Makiki to Nuuanu and back, but she was surprised at how quickly it passed.

"Now, I’m the crazy one," she said.

Tellei enjoys the variety of terrain on the trails at Tantalus, which include stream crossings, roots, rocks and boulders. Her favorite part is running downhill.

Running on the trails is a great overall conditioner, with less wear and tear on a person’s body than running on roads, according to Tellei.

"Every inch of your body has to work to stabilize itself," she said.

The H.U.R.T. 100 takes more mental than physical stamina, plus discipline in training. Tellei started out as a pacer, someone who helps the endurance runners complete a loop at night, making sure they stay on the trail and don’t fall asleep.

Running all night is part of the training for the endurance run, which consists of five 20-mile loops at Tantalus that have to be completed within 36 hours.

To prepare, runners typically do back-to-back runs on weekends — 20 miles on a Saturday, for example, followed by another 10 miles on Sunday.

As a working mom — she’s manager of the PATH Clinic for women for the Waikiki Health Center — Tellei has to get up at 4 a.m. on weekdays or squeeze in an afternoon run between work and picking up her children from their various sports.

"It takes everybody," she said, crediting the support of family — including a husband who cooks when she’s not home, and her children, who sometimes run with her. When she ran her 100-miler, they were all there to cheer her on.

While she took a break from the H.U.R.T. 100 this year, she hopes to run it again.

She compared the H.U.R.T. 100 to childbirth without pain medication, which she did three times.

"It was physically exhausting, mentally exhausting," she said. "The part that was different, at some point with childbirth, your body goes into its own motion and it does it. Not with H.U.R.T. If you stop running, you’re done."

But she doesn’t plan to stop. She wants to keep on running well into her 70s and 80s.

"This is what makes me happy," she said.

"Good Fit" spotlights inspiring fitness stories of change, self-discovery and challenge, and other fitness-related topics. Tell us what motivates you and how you stay fit and healthy. E-mail features@staradvertiser.com.