US marathon swimmer Diana Nyad continued to pursue her "Xtreme Dream" to swim across the shark infested waters of the Florida Straits, from Havana, Cuba to Key West, Florida.
"22.2 miles into swim, Diana, swimming at 50 strokes per minute, looks comfortable and confident," a message posted to her Twitter account (http: twitter.com diananyad) said early Sunday afternoon, after nearly a full day of swimming, reports Xinhua.
The long-distance swimmer jumped into the waters off the coast of Havana Saturday afternoon, a day earlier than planned, to take advantage of good weather and water conditions for the 166-kilometre, 60-hour swim.
That message contrasted starkly with earlier postings of kayakers swimming alongside her to keep sharks away and an almost constant attack by jellyfish.
Nyad, 62, suffered "multiple jellyfish stings, on her lips, forehead, hand, and neck" throughout the night, but was still going strong, her website said.
If successful, Nyad will become the first person ever to swim the 166-kilometre straits, without the use of a protective anti-shark cage. Yet she has been forced to abandon three previous attempts, the last in September 2011, after swimming for 40 hours and covering two-thirds of the distance.
A month earlier, in August 2011, she was forced to call off another try after 29 hours of swimming, following an asthma attack and strong waves.
Donning a blue-and-black swimsuit and blue swim cap, Nyad dived into the waters of Havana's Marina Hemingway yacht club at 3:42 p.m. local time (19:42 GMT) Saturday, under a bright sunny sky.
Nyad's biggest challenges to reaching the tip of Florida, besides sharks and jellyfish bites, are the strong currents of the Gulf of Mexico and dehydration, hypothermia, disorientation and other physical symptoms of endurance tests.
A team of some 30 assistants, among them shark diving experts, are accompanying and monitoring Nyad's swim aboard yachts and kayaks, in case the electric devices she is equipped with fail to keep the predatory sea creatures at bay.
Nyad first tried to swim the Florida Straits in 1978, but bad weather forced her to cancel the attempt after 42 hours in the water.
The champion swimmer, who turns 63 Wednesday, still holds the world record for endurance swimming that she won in 1979, when she swam 165 kilometres from Bimini, Bahamas, to the Florida Keys without a wetsuit.
At the beginning of July, strong gulf currents forced British-Australian swimmer Penny Palfrey, 49, to abandon her attempt at swimming the straits after 40 hours. She had only 43 kilometres to go before reaching Key West.