Portugal Colonial - Fear the biggest rival: first person to complete Antarctic 2.5 km swim

The 37-year-old completed the feat in 45 minutes and 30 seconds on February 5, wearing an ordinary swimsuit without additional padding, some goggles, a swimming cap and ear plugs.

Her only defense against a cold that would have killed many others: perseverance. The water temperature reached barely 2.0 degrees Celsius (35.6 Fahrenheit).

"My biggest rival is fear... not (other) people," Hernandez told AFP after completing the glacial endeavor recognized as a first by the International Winter Swimming Association. She hopes it will also be inscribed in the Guinness World Records.

"Fear of failure, of failing the people who trust in me, those are my main adversaries," said the Chilean swimmer nicknamed "The Ice Mermaid."

Hernandez recounted her mind-over-body struggle completing the distance -- about the length of 25 football fields -- which started from a Chilean Navy ship near Greenwich Island in Antarctica.

Shortly after half-way, she said, "I felt something cold passing through my heart" -- a known sign of hypothermia setting in, with the risk of heart attack and death.

She did the only thing she knew how: she kept kicking and wading until she reached the finish: a buoy in the middle of the ocean.

"It was a super difficult swim, tough," Hernandez told AFP.

"After completing the first mile I felt that I would never reach the buoy... I felt... my arms getting heavier and heavier," she said. "But I did not concentrate on that."

- Melting Antarctic -

Hernandez said she had dreamt of the moment for a decade. But it is not only about pushing herself. She is also using her public profile to advocate for marine protection.

"What scares me is that Antarctica keeps melting. That really scares me," she said.

"When I was swimming, that was one of the things I was thinking about. My legs hurt, but I felt strong. I thought: This is not just for me, it is the cause we wanted to make visible. That gives you a boost."

Last week, the National Snow and Ice Data Center in the United States reported that the Antarctic Ocean area covered by ice has shrunk to a record low.

By the time she got there, her body temperature was just 27 C -- far below the average of about 37 C for a person in good health.

She never lost consciousness, though she did ramble incoherently for a bit. Within two hours, she was back to her old self, Hernandez recounted.

Her next challenge will be the Oceans Seven marathon that consists of swimming through seven channels or straits around the world, finishing in Japan in August.

P.Sousa--PC