She’s in it for the long run!

A tough-as-nails 80-year-old New Jersey grandmother became the oldest woman ever to finish the grueling Ironman World Championship over the weekend — and now she says the key to staying fit in old age is to “keep moving.”

“I’m never close to giving up,” Natalie Grabow, of Mountain Lakes, told The Post Thursday. “I love the feeling of working hard and accomplishing a goal.”
Grabow has competed in 10 other Iron Man races on the island.Getty Images for IRONMAN
Grabow pushed through a minor hamstring injury, rough waves and intense humidity to run 26.2 miles, bike 112 miles and swim 2.4 miles in the open ocean on Saturday during the race in Kailua-Kona, Hawaii.

The mother of four and grandma of two completed the notoriously tough triathlon in 16 hours, 45 minutes and 26 seconds — on a day when more than 60 other athletes of all ages quit.

Grabow, who has competed in 10 other Iron Man races on the island, offered some sage advice on how to stay healthy and fit well into your golden years.

“Whether you choose pickleball or dancing or whatever, it’s just really important to move your body and stay strong. Especially as you get older, when you feel strong in the body, you feel strong in the mind — they go together and it gives you confidence,” she said.

“You really just have to keep moving,” she said. “And I would say be consistent with it.”

During the race on Saturday, swimming in the choppy water was the hardest part, she said.

“It’s always a contact sport,” she said. “You’re always getting hit in the head, and my googles were kinda getting knocked off,” she said — adding that she was “swallowing salt water.”

Along with rigorous training and a little good luck, the key to not giving up is to constantly check in with your body, she said.

“Some of the best women pros have problems with overheating. You never know what your body is going to do. It’s a matter of really constantly evaluating how you feel and what you need; what nutrition you need,” she said.
Grabow pushed through a minor hamstring injury during the grueling triathalon.Getty Images for IRONMAN
“[That way], I always stay mentally good, so I don’t get fuzzy or feeling like I’m not gonna go on.”

She stumbled and fell moments before reaching the finish line — but quickly got back up and completed  the race as her coach and daughter cheered her on.

“It feels wonderful,” she said. “It’s really great to feel like you’ve done your best and given it everything you have.”

Grabow, who learned to swim at age 50, said she had a coach and a training routine that involved running, swimming and biking generally with one long day a week.

To prepare for the scorching race, she said she closely monitored her nutrition and “got my salt in.”

The first meal she had after the race was a chicken wrap and she spent the morning after in bed eating a bagel with lox and cream cheese while recovering, she said.

She now plans to give herself a week off for recovery — may soon do another Iron Man triathlon outside of Kona.

Next time, the goal may be to “match” Madonna Buder, who holds the current world record for the oldest woman to ever finish any Ironman race at 82, she said.

“But you can’t say how you’re gonna feel at 82 when you’re 80,” she said. “You just have to enjoy the day to day.”