Elite Athlete Reveals Shocking Side Effects After Swimming in the Ocean for 21 Hours Straight (Exclusive)

After narrowly missing a spot on her third Olympic team in 2019, a moment that could have marked a quiet end to her elite swimming career, Rebecca Mann chose a different path – one defined by resilience, reflection, and her daring spirit. 

As a two-time USA National Champion, the athlete set her sights on something extraordinary: a nonstop, 40-mile swim between the Hawaiian islands of Maui, Molokai, and Lanai, known as the Maui Nui Tri-Channel Crossing.

At just 10 years old, Mann swam the nearly 10-mile channel from Lanai to Maui, called the Au'au Channel.

Over a decade later, the athlete marked what she thought would be the end of her competitive career by pushing her limits once more – a way to celebrate all she had trained for throughout her life.

Before the daunting journey, her longest swim had been 25 kilometers — about 15.5 miles — at the World Aquatics Championships in 2017.

When she embarked on the Maui Nui Tri-Channel Crossing, the then-21-year-old didn't know what to expect.

“I didn't really know where I was in the ocean. I didn't know how long I was going to be in the ocean, and I kind of just had to tell myself: ‘you can do anything,’” Mann tells PEOPLE exclusively. 

She found the swim more mentally challenging than physically. While every stroke was painful, the discomfort was manageable, never overwhelming to the point that she couldn’t keep going. “I just reminded myself when things got really bad…I want to quit even less than I want to swim,” she recalls. 

After nearly 21 hours of constant exertion, she became the first person ever to complete the grueling, three-point swim.

However, the journey wasn’t about breaking records; it was a statement of purpose filled with love for the sport that shaped her. 

Mann recently took to TikTok to share insight into the experience, striking a chord with athletes and dreamers alike. 

After sharing her feat online, followers flooded her social media with questions about sleep, food, and, most importantly, any sea life encounters. 

“The only time I will ever skip a night of sleep is if I’m swimming through it because I love my sleep,” Mann said in one of her TikTok videos. The athlete tells PEOPLE that she followed a 20-minute feeding schedule, with her mom tossing her “liquid fuel” – a mix of Gatorade and melted energy gel. 

Luckily, Mann had no shark encounters, but she did suffer from something equally as terrifying: severe swelling due to the salt water. “When I was getting towards the end, I was worried about my throat closing,” she reveals. 

About nine hours into the swim, her nostrils became swollen together, and she couldn’t breathe out of her nose. “But that wasn't a big deal for me because I was like, 'Okay, it's fine. I can breathe through my mouth,'" she says. "But then my uvula started hanging down onto my tongue.”

Mann remembers not being able to swallow for hours after the swim. It took her two whole days to fully recover from the swelling – something she hadn’t foreseen. Another unexpected result of her 21-hour journey was the recurring dreams she started having six months later. 

“I start having these dreams where I'm just stuck in the ocean and they're scary, but they're also not scary at the same time,” she says. “It's just really strange. I'm always in the middle of the ocean trying to do the swim, and I'm not in good enough shape, and there are a bunch of sharks around me, and I don't have a boat next to me, and it's really bizarre.”

Nearly six years since the swim, Mann continues to have these dreams, despite not being afraid of sharks in real life. Regardless, she says she would "absolutely" do it again.

As an individual struggling with Obsessive-compulsive disorder (OCD), she admits that her thoughts would spiral during the long hours of swimming, leading to a few panic attacks. But she reminded herself it would pass and focused on staying present in the moment.

“When I go through a challenge - that's my best self,” Mann explains. “I think that it teaches me a lot about myself, and it reminds me of who I am, who I want to be, and I think that's the biggest lesson; just getting through all of the bad parts of life.”

At one point during the swim, overwhelmed by emotion, she realized how grateful she was for the path she had taken. Had she made the Olympic team, she wouldn’t have been in the middle of the ocean, swimming under a sky full of stars with no light pollution — one of the most incredible moments of her life.

Undeterred by the disappointment of Olympic defeat, Mann was determined not to let that moment define her. She published two books, including a young adult dystopian novel, Unruly, in April 2025.

Meanwhile, the 27-year-old's memoir, Outside the Lanes, offers a powerful reminder that the end of one dream can be the beginning of something even greater.

She is now in the process of making a comeback after a five-year break from swimming. 

“We’re often told that if you give everything, if you work hard, if you believe in yourself, you’ll succeed,” she said in a TikTok about her memoir.

“But sometimes you don’t, and that’s awful, but that doesn’t mean you can’t use what you learned and apply that to other aspects of your life, or that it was all for nothing. It’s about the journey, not the destination."