HAVANA — Marathon swimmer Diana Nyad was making good headway through the Florida Straits despite some physical complaints Monday, about one-third of the way into her attempt to log a record swim at the age of 61.

While Nyad was pausing only briefly for nourishment and is not allowed to touch

the support boat, her team kept fans and well-wishers up to date through social media.

“Diana is swimming strongly. The swells have subsided,” said someone posting on her Twitter account in the morning.

“We’re very pleased with her progress,” her Facebook page read.

Alexandra Crotin, a spokeswoman for the swim, said in an e-mail to The Associated Press Monday evening that “as of 3:15 PM EST … Nyad was 35 miles from Havana, Cuba. … She was 75 miles from Key West.”

Crotin said Nyad hopes to end her swim at the Southernmost Point in Key West.

Both social media accounts said in the afternoon that she was experiencing some shoulder problems and asthma, but doing well.

Nyad is trying to accomplish at 61 years old what she failed to do at 28: swim an estimated 60 hours covering 103 miles (166 kilometers) from Havana to Key West. This time she’s even attempting the swim without a shark cage, relying instead on an electrical field from equipment towed by kayakers to keep them at bay.

Nyad would break her own record of 102.5 miles (165 kilometers) for a cageless, open-sea swim, set in 1979 when she stroked from the Bahamas to Florida.

She’ll have to overcome fatigue and potential debilitating problems like nausea and chafing from the salty water. She said she was bringing along 25 pairs of goggles — including light blue for nighttime vision and darker ones for daylight — and any suit changes will happen right there in the water.

At least the weather and water conditions, which thwarted her previous attempt at the Cuba-US swim in 1978, seem to be in her favor.

The sea was flat as a pancake around sunset Sunday when she began her journey.

“This is what I dreamed of: a silver platter,” Nyad said before hopping into the water feet-first from a Havana jetty.

Monday dawned much the same in Havana — calm waters, muggy, with just a hint of a breeze. The favorable conditions are predicted to last until Thursday.

Nyad told journalists she hopes her swim will inspire others her age to live active lives. She also hopes it can help improve understanding between Cold War rivals Cuba and the United States, even if just symbolically.

She expressed love and admiration for the island nation and promised to come back soon for a post-swim party.

Whether that will be a victory bash remains to be seen, but a quote by Nyad posted to her Twitter account suggests she’s determined to go all the way.

“If I go unconscious, that’s one thing,” it read. “But no one is going to make me get out of the water, that will never happen.”