U.S. swimmer Diana Nyad begins her swim from Cuba to Florida

(AP)  — Endurance athlete Diana Nyad pressed on despite painful jellyfish stings and kept swimming treacherous ocean currents beneath the stars early Sunday, about halfway through a grueling course from Cuba to Florida.

As of the latest update before sunrise, her crew said the 62-year-old swimmer had completed 49 miles of the 103-mile passage of the treacherous Florida Straits and was swimming beneath a nighttime sky bristling with stars. If all goes well, she hopes to complete her sea swimming odyssey Monday morning.

Updates have been coming from her handlers via Internet posts, and already Nyad has been in the water longer than her aborted attempt at a Florida Straits crossing last month, when she lasted 29 hours before a crippling asthma attack forced her to call it quits.

Her latest attempt also has been fraught with difficulties.

Nyad suffered a weekend jellyfish sting that painfully affected her face and eyes and was treated late Saturday aboard a support vessel. But her team tweeted early Sunday that she hit the water again and was continuing her methodical strokes toward her goal. Her website said she had completed more than 34 and a half hours in the water soon after 4:30 a.m. EDT (0830 GMT) Sunday — or more than 93,000 strokes.

An independent observer said she could still pursue her attempted record-setting swim from Cuba to Florida despite seeking treatment.

Nyad’s team said early Sunday in a post on her website that the record would still be valid as long as she was on the boat only for treatment and not to rest. It didn’t elaborate on the specific treatment she received or how long she was out of the water, but a team blog update posted before dawn said she resumed swimming at the “exact spot” where she had paused.

“The rules say she is now going for a record staged swim rather than a non-stop swim,” the updated noted.

Her organizers said making it through the second night would be a key test to completing her swim as she struggles with the physical and mental challenges of such a distance. Her website said she was breaking up the swim into manageable blocks of time and getting through difficult nighttime hours by recalling favorite songs and thinking upbeat thoughts.