Peloton's Jessie Malone is running a marathon to mark one year since her Apple Watch saved her life by revealing a heart condition she was completely unaware she had.

Malone is not just a young and fit woman who exercises regularly, she's a producer for Peloton in New York. Yet as she was cycling home in May 2023, her Apple Watch alerted her that she might have atrial fibrillation.

"It was saying you need to seek medical attention immediately," she told Today.com, . "It was red and vibrating. I was like, 'Oh my God.'"

Her heart rate while she was cycling had risen to 160 beats per minute, but she says she hadn't felt anything other than a little nausea. Following her Apple Watch "blaring that my resting heart rate was elevated and also that I had gone into Afib," she says she dumped the electric bike and went to an emergency room.

"Suddenly I'm surrounded by eight doctors," she continues. "That's when one of the doctor's first question was, 'Has anyone in your family ever dropped dead with no explanation? And I was like, 'Whoa, what?!'"

Doctors wanted to restart her heart with a defibrillator, but the necessary medication to first stop her heart did not work. Other medication got her heart rate down to 130bpm and admitted her to hospital.

Malone says that she had no underlying condition, and there is no genetic predisposition toward heart issues. However, she says that she had been sleeping poorly, and also drinking a lot of caffeine.

"The doctor was under the impression that [the combination of these] might have built up and gotten to such an extreme that it caused the Afib," she says. "It was the perfect storm of essentially living in New York City and not taking care of yourself properly."

Malone has to be up at 5 A.M. for her role as a producer at Peloton, and she can't change that. But she says she has cut out caffeine, alcohol, and has changed her diet.

"I prioritize sleep in a very big way," she adds. "It is mostly about me getting myself back in a healthy way."

She's also been building up her exercising, and in early May 2024, will be running a marathon in Washington, D.C. It is specifically to celebrate the year since she was hospitalized.

"I feel like a completely different person with so much more energy," says Malone. "You need to prioritize your own health — that's the most important thing."

Atrial fibrillation is an irregular and highly elevated heart rhythm, which the Apple Watch has been able to detect since the Apple Watch Series 4 was introduced in 2018.