(RNN) - At 61-years-old, Diana Nyad tried to achieve what youth never could - to be the first to successfully swim the 103 miles between Cuba and Key West.
A Twitter feed for Nyad said she stopped 29 hours into the swim due to rough currents and strong winds.
"Diana herself decided to end the swim. The combination of factors was too much to safely continue," her crew members said in Tweets.
Her dream was put to sleep 33 years ago when, after fighting stiff winds and waters for nearly 42 hours in a previous attempt, she fell short of achieving her goal.
"The one dream I didn't fulfill as an athlete, I didn't make it in 1978 from Cuba to Florida," she said in a video posted on her website. "We went out on a raging sea. It was the wrong day and I can't beat the weather."
At 7:45 p.m. Sunday, an older, wiser Nyad plunged in to a much calmer sea off Havana and began her quest anew.
It would have been a 60-hour, non-stop journey - quite a feat for a swimmer of any age.
"If I go unconscious, that's one thing. But no one is going to make me get out of the water; that will never happen," she posted on her Twitter account Monday.
In her 20s, Nyad was a champion long-distance swimmer. She became the first woman ever to swim around Manhattan Island in 1975 and set a world record, swimming 102.5 miles from the Bahamas to Florida in 1979.
Then, suffering from burnout, she ended her competitive career, not swimming a stroke for 31 years.
But with age came a lot of soul searching. One dream still eluded her. Time was passing, but she could, in some ways, rewind the clock and conquer the one feat in her career she felt was left unaccomplished.
Staring down her 60th birthday, she threw herself into training. A year later, visa troubles and a string of Atlantic hurricanes thwarted her attempt to try in the summer of 2010.
After an unexpected extra year to train, she says this time, she's stronger than ever.
She was flanked by a boat full of teammates who feed her a liquid mix of nutrients, electrolytes and calories through a Camelback. She's not allowed to touch the boat.
LED lights guided her at night.
She's also swimming without a shark cage. Two kayaks equipped with shark repelling devices escorted her every stroke of the way.
Through her first full 24 hours, she'd already battled through some shoulder pain and a touch of asthma, but after a few more hours the winds and seas became too hard to handle.
"Nobody decides the swim is over except me," her team tweeted on her behalf.
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