The tennis great was carried down Mount Kilimanjaro on a litter Thursday night and Friday morning. Navratilova said she knew by Wednesday she wouldn't be able to summit the 19,340-foot (5,894-metre) mountain in Tanzania.
"I didn't feel badly, I just couldn't breathe. I couldn't get a full breath of air," Navratilova told reporters shortly after being released from the hospital, where she was treated for high-altitude pulmonary edema.
"Nothing hurt, and for an athlete that's weird. Nothing hurt but I (couldn't) go on," she said. The 54-year-old, who had a bout with breast cancer earlier this year, reached nearly 14,800 feet (4,510 metres) when a doctor with 27-person climbing team told her she needed to descend.
Quitting, Navratilova said, is not in her vocabulary, but "when the doctor said you're going down, you're going down." She was disappointed and frustrated, but trying to push on would have been dangerous.
The winner of 18 singles Grand Slams, Navratilova kept a diary during her four-day climb. Her last entry read:
"'I've never been so utterly exhausted. Everything is taking monumental effort, going to the bathroom, getting dressed, setting up tent. I don't want to ever ...' I can't read it. I stopped writing because I was crying, because I was so disappointed at how I felt," Navratilova said.
She wrote the entry Thursday afternoon, a few hours before descending.
Two days before beginning the climb up Navratilova told The Associated Press that she was in good enough shape to get to the top but that she didn't know if "the altitude will get me. That's something you can't predict."
Once down from the mountain, Navratilova's appetite returned. She said she hadn't been hungry for four days, though at first she thought it may have been an intestinal issue after eating bad fish today.
Kate Brewer, a press agent for the sports company Laureus who was also on the climb, said the mountain guides told the group that the weather was the worst they had ever seen. Torrential rain, mist and cold plagued the group.