KEY WEST, Fla. (AP) -- Disappointed marathon swimmer Diana Nyad gave up on any more attempts to cross from Cuba to Florida after ending her second bid mid-channel Tuesday because of wind, currents and health problems.
The 61-year-old left Cuba on Sunday but said asthma and shoulder pain contributed to ending her second try in 33 years to swim the Florida Straits.
"This was such a dream. For two years, I pictured myself walking up on that shore, and I wanted that moment badly," Nyad said after her support boat docked in Key West.
Doctors used inhalers and various medicines to try to open up her lungs as she was swimming, but the veteran swimmer said she "was so depleted of oxygen and I was limping along."
As the water turned choppy and her condition worsened, Nyad said her dream of finishing the swim was so strong that she vowed to doggy paddle her way to the finish line if that's what it took. But by midnight, she was trembling and spent from the asthma attacks.
"I think I'm going to have to go to my grave without swimming from Cuba to Florida," she told CNN.
According to her Twitter feed, Nyad was pulled from the water early in the morning after swimming for 29 hours. The swim was expected to take 60 hours to cover at least 103 miles (166 kilometers).
"It was so hard. I couldn't even swim. I couldn't be the swimmer I am. I had severe asthma for 11 hours-I was taking 10 strokes and then going on my back and gasping. I had severe pain in my right shoulder that was so excruciating that every stroke I took from the third hour all the way through 30, I just winced every time," she said.
The Twitter account reported she decided to end the swim herself, after "realizing the conditions of 5 to 10 knot winds and less than ideal currents." An online chart plotting the swimmer's track showed the Gulf Stream currents pushing Nyad to the east of the intended course. Nyad had hoped to end her swim at Southernmost Point in Key West, Fla.
In her second attempt, Nyad tried to accomplish at 61 years old what she failed to do at 28 in 1978. This time, she even attempted the swim without a shark cage, relying instead on an electrical field from equipment towed by kayakers to keep them at bay.
In her first attempt in 1978, she quit after being in the water for 41 hours and 49 minutes due to strong currents and rough weather that banged her around in the shark cage.
Had the latest attempt been successful, Nyad would have broken her own record of 102.5 miles (165 kilometers) for an open-sea swim without a shark cage, set in 1979 when she stroked from the Bahamas to Florida.
Before the swim, Nyad told journalists she hoped her swim would inspire others her age to live active lives. She said she also hoped it could help improve understanding between Cold War rivals Cuba and the United States, even if just symbolically.