A 16-year-old and her mom just ran themselves into the record books — together, stride for stride, for nearly five hours straight.

  • 31.07 miles covered by Natalia and Cienna Lazarus, side by side, the entire way
  • 9 hours, 56 minutes, 20 seconds — their combined finishing time
  • 16 — Cienna's age, exactly the minimum Guinness allows for this record
  • $7,500 raised for anti-trafficking nonprofit Venture

Running side by side for five hours

Danville's Natalia Lazarus and her daughter Cienna, a student at San Ramon Valley High School, ran a 50-kilometer ultramarathon together on June 20 in Cerritos, California. Both finished in under five hours, and last week Guinness World Records officially certified them as the fastest mother-daughter duo ever to complete the distance together.

The certification took months. Lazarus says they didn't get official word their run had broken a record until September 11 — nearly three months after they crossed the finish line. Cienna, who runs track and cross-country for her school, just barely cleared the minimum age of 16 that Guinness requires for the category.

Natalia, who works as a health and fitness coach, had already completed The Great World Race the previous November — seven marathons on seven continents in seven consecutive days, one of only 60 runners worldwide to attempt it that year. Cienna joined her for the final leg, in Miami.

"Whenever I faced a moment where it felt like I wanted to give up, the thought of the children we were doing this for empowered me to keep going," Cienna said.

A cause bigger than the finish line

That's because the 50K wasn't just about the record. Through the race, mother and daughter raised $7,500 for Venture, a nonprofit focused on anti-human-trafficking work, turning months of training into a fundraising campaign built around a shared cause.

Training took over their household for months beforehand — and, according to Natalia, the mental preparation mattered as much as the physical mileage. "There's always the physical training that goes into a race like this, but the mindset training was the most important part," she said. "Even when you're in the best shape of your life, 31 miles of continuous running, just under five hours with no walking, takes its toll."

For Natalia, the record is really a byproduct of something else: a mother and daughter who now share a serious running habit, and hopefully more record attempts to come. "I hope this is the beginning of big running adventures we share together," she said, "as mother and daughter."

On the Guinness World Records page for the achievement, the organization added its own note of encouragement: "Natalia and Cienna hope to challenge other mothers and daughters to chase big dreams!" It's a fitting coda to a record that took five hours to set and three months to confirm — proof that some of the most meaningful finish lines are the ones you cross holding someone else's hand.