MIAMI -- Marathon swimmer Diana Nyad spent more than 40 hours in the shark-filled waters between Cuba and the Florida Keys, climbing into a boat only to be treated for searing welts left by Portuguese man o' war stings. Left swollen and red, Nyad had no choice but to end her trek early when medics warned another sting could be deadly.
The 62-year-old soldiered on for a time, cutting eye and mouth holes into a cap she wore over her face to protect against future stings. She surpassed 100,000 strokes, but the stings -- which team members said left what looked like branding marks from the jellyfish-like creatures' tentacles -- were too much of a risk.
"I trained this hard for this big dream I had for so many years, and to think these stupid little Portuguese man o' war take it down," Nyad told The Associated Press, just hours after getting out of the water. "It's a huge disappointment."
She said she was in the best shape of her life but was blinded by the stings. Late Sunday morning, she heeded the warnings of experts who told her not to continue another two days in the water.
"You go into convulsions, your spine feels paralyzed. I've had kidney stones. Nothing compares to the pain," Nyad said, wearing loose bandages and rehydrating with water and juice on her boat. "It just took the life force out of me."
Nyad arrived Sunday evening in Key West, where she spoke with reporters. She walked off her boat "Sunluver" wearing a white bathrobe, her face and lips swollen from the stings, and pulled up a sleeve to show a long cross-shaped welt on her right forearm.
"It's such a bitter pill," she said. "I am so capable of that swim. That's the end though."
"Because if it was the weather or Tylenol, but those damned jellyfish," she added.
Nyad said that as she swam, she felt paralysis in her back. She recalled swimming through the two stings, which she described as like something out of a sci-fi movie when the tentacles whipped across her.
"I went through two of them and I kept swimming," said Nyad, who wore long pants and a long-sleeved shirt while swimming. Her clothing covered everything but her hands feet and lips, and she got stung in the lips.
"My lips are like Angelina's," she quipped.
But Nyad said she also took pride in swimming for 40 hours, saying she did much better than in a previous try in August. She said visions of the Florida coastline helped keep her going.
"I pictured it," she said. "I really pictured it. I knew I could do it. I just couldn't get there. I wanted that feeling to be on the beach so badly. I'm just not going to have it."
Her team tentatively scheduled a press conference in Key West for Monday morning.
Nyad was making her second attempt in as many months at the Cuba-Florida crossing, a lifelong dream that she first tried as a 28-year-old back in 1978, when she swam inside a steel shark cage for about 42 hours before ending the attempt. A cageless attempt this past August fell short 29 hours in when, gasping for breath, Nyad threw in the towel after an 11-hour asthma attack she blamed on a bad reaction to a new medicine.
Australian swimmer Susie Maroney successfully swam the shark-filled waters from Cuba through the Straits and to the Keys in 1997, though she used a cage. Nyad was trying to become the first to finish it without a cage.
Earlier in her latest swim, Nyad received oxygen and a steroid shot from her doctors and was treading water while she recovered from the stings.
After that, her team said in a website update that a so-called "staged swim record" would still be valid as long as she was on the boat only for treatment and not to rest -- rather than a nonstop record.
Nyad's website said she spent the night trying to recall favorite songs and thinking upbeat thoughts while slipping through the waters under a nighttime sky bristling with stars and a sliver of a crescent moon.
The swimmer faced other obstacles aside from the man o' war stings. On Saturday, handlers spotted barracudas in the area, and she got a visit from a curious Oceanic white tipped shark that was shooed off by a support diver.
Without a cage to protect her, Nyad relied on equipment surrounding her with an electrical field that is harmless but deters most sharks. Her divers are there to gently discourage any who make it through. But not all encounters with marine life were unpleasant. Earlier in her journey, 10 pilot whales emerged in the distance ahead of the swimmer, according to one team tweet.
The Los Angeles woman regularly paused to rest and refuel on food that her assistants passed to her in the water, but without getting on the boat. To maintain her strength she ate pasta, bananas, bite-size pieces of peanut butter sandwiches, and high-calorie and high-carbohydrate drinks.
Dozens of well-wishers flocked to social media sites Sunday after Nyad climbed out of the water, calling her an inspiration.
The athlete in her is still battling disappointment, but Nyad said she's working to gain a positive perspective focusing on the camaraderie from the two-year effort.
"I can live beyond it and think of all the good that's come of it, just to live a life of passion," she said.