09/30/2013 at 02:15 PM EDT
After completing a grueling 110-mile swim
from Cuba to Florida, Diana Nyad spent a week recovering on Dairy Queen milkshakes.
"I stayed away from food for a week," she says, explaining the inside of her mouth was severely damaged
from the salt water. "I was more dazed and physically exhausted than I thought I was going to be."
But that's not stopping her from gearing up for another big swim.
"My mind and body will be absolutely ready for this next swim," Nyad, 64, says. "I'm not out all night partying and staying up all night."
And her next swim will be slightly less hazardous to her health. From Oct. 8 to 10 Nyad is hitting the water to raise money for Superstorm Sandy survivors through Nyad Swim for Relief via AmeriCares
"Because it's a pool we won't have the wind action, and of course there won't be jellyfish and sharks," says Nyad of the 48-hour undertaking, where she'll be accompanied by locals and celebrities swimming laps alongside her in a specially designed pool being built in New York City's Herald Square. "But still, there are very few people on earth who have swam for 24 hours, much less 48. I don't want to be a fool and not be able to make it through his swim and give up half way. I want to make sure that they know we care."