American endurance swimmer Diana Nyad failed over the weekend in her second attempt in the last two months to cross the Florida Straits after swimming for more than 40 hours without a cage to protect her from sharks, Cuban media reported.

The 62-year-old Nyad was stung twice by jellyfish and decided to call off the swim on Sunday morning, Cuban media said, citing a posting on her personal blog.

"The medical team said I should not go another two nights in the water and risk additional likely man o'war stings which could have a long term cumulative effect on my body," Nyad said in a posting on her Web site about her latest attempt to cross the 166 kilometers (103 miles) between Havana and South Florida.

After using 117,000 strokes in the 67 nautical miles she completed of the 103 that separate the two coasts, the veteran swimmer said while still in the water that she would continue to pursue her dream.

"But for each of us, isn't life about determining your own finish line? This journey has always been about reaching your own other shore no matter what it is, and that dream continues," Nyad said.

This is the third time Nyad has tried to achieve her goal of being the first person to beat the record for swimming across the Florida Straits without a cage to protect her from the sharks that abound in those waters.

Her first attempt in 1978 ended after 42 hours at sea because of bad weather, and last Aug. 7 she had to abandon her project due to exhaustion that brought on an asthma attack lasting 11 hours.

Though now retired from active sports, Nyad has been in training the last two years for this swim of some 60 hours, with rest stops planned for every 45 minutes to drink water, eat some light food like chocolate and fruit, and put on clothes if that should prove necessary.

Her team included oarsmen and divers to protect her from a possible shark attack with a GPS system and devices emitting electric waves to repel sharks.

During her sports career, Nyad was the world's top long-distance swimmer, according to her team, and set a number of records, including swimming around Manhattan in 7 hours 15 minutes when she was 50 years old.