Nyad said, "It's such a bitter pill. I am so capable of that swim. That's the end, though," implying that she won't make another attempt. Nyad is 62. "Those damned jellyfish," she added.
Nyad's encounters were with the Portuguese Man O'War, which is jellyfish-like, and stings like a jellyfish, but isn't actually one. To her, it doesn't matter. There are still stings with toxins injected into the body, and those are cumulative.
Nyad showed off welts from the stings to reporters. Nyad said her team told her, "These stings are cumulative. What makes you think you'll get through dusk again? They're everywhere.
"You go into convulsions, your spine feels paralyzed. I've had kidney stones. Nothing compares to the pain. It just took the life force out of me. I trained this hard for this big dream I had for so many years, and to think these stupid little Portuguese man o' war take it down."
After her first encounter with a man o'war, Nyad received a steroid shot and oxygen, but remained in the ocean, treading water. The second time, she was forced by officials to receive treatment in her support boat. That changed the swim type. Instead of trying to set a nonstop swimming record, she would, if she continued, be trying to set a so-called "staged swim record," which would be valid so long as she was on the boat only for treatment and not to rest.
Eventually, though, she was forced to quit. The time between in-water rests had dropped from 90 to 40 minutes, and that meant the total length of time for the swim would have forced her to make it through two more nights in the water, with the likely result being more man o'war stings.
The Portuguese Man o' War is found in warm water seas floating on the surface of open ocean with an air bladder to keep it afloat. The air bladder also acts as a sail while the rest of the organism hangs below the surface. It has no means of self-propulsion.
It has tentacles similar to a jellyfish, but unlike a jellyfish, the Man o' War is a siphonophore, which is not actually a single creature like a jelly, but a colonial organism made up of many tiny individuals called zooids.
According to Wikipedia:
[Man O'War] "stings usually cause severe pain to humans, leaving whip-like, red welts on the skin that normally last 2 or 3 days after the initial sting, though the pain should subside after about an hour. However, the venom can travel to the lymph nodes and may cause, depending on the amount of venom, a more intense pain. A sting may lead to an allergic reaction. There can also be serious effects, including fever, shock, and interference with heart and lung function. Stings may also cause death, although this is extremely rare. Medical attention may be necessary, especially where pain persists or is intense, if there is an extreme reaction, the rash worsens, a feeling of overall illness develops, a red streak develops between swollen lymph nodes and the sting, or if either area becomes red, warm and tender."
Image Source: Wikimedia Commons