Doctors said veteran long-distance swimmer Diana Nyad's tongue and lips are swollen as she makes the final push for the Florida coast.
Dr Kot and Dr Covington, part of Ms Nyad's support team, said her speech is slurred as a result of the swelling.
Although they are concerned about the 64 year old's airways, they have not intervened in her attempt at swimming from Cuba to Florida without a shark cage.
Twitter users have posted messages of support on the social networking site for US swimmer Diana Nyad.
Ms Nyad is closer than ever to becoming the first person to complete the journey from Cuba to Florida without a shark cage:
US veteran long-distance swimmer Diana Nyad is just a few miles away from becoming the first person to complete the 103-mile journey from Cuba to Florida without a shark cage.
Ms Nyad's navigator, John Bartlett, said she was at "a distance not ever having been close to achieved by any other human being before."
US swimmer Diana Nyad said this will be her final attempt at making the 103-mile journey from Cuba to Florida without a shark cage.
Ms Nyad said before beginning the gruelling swim, "I'm learning as I get older, and I'm really getting older now, that there's a fine line between having grace and letting go of something that you have no control over and you're just not going to beat, like Mother Nature maybe."
Veteran long-distance swimmer Diana Nyad is edging closer to becoming the first person to complete the 103-mile journey from Cuba to Florida without a shark cage.
The 64 year old American has made it farther than in any of her previous four attempts and is expected to arrive in Key West later today, according to her representatives.
Ms Nyad's journey began on Saturday morning when she jumped from the seawall of the Hemingway Marina into the waters off Havana with the cry "courage".
She has been swimming the Florida Strait ever since, stopping from time to time for nourishment.
Ben Friberg is attempting to become the first person to Standup Paddle Board non-stop 90 miles from Port Hemmingway in Cuba to Florida's Key West.
He says the trip is aimed at promoting "peace and love and friendship...between Cuba and the United States as well as healthy lifestyles".
A recent tweet from the Twitter account detailing the American's progress, said: "Ben is hanging in there and showing perseverance through the choppy waters!".
Two MiG-21 fighter jets have been found on a North Korean ship stopped in Panama.
The Chong Chon Gang had left Cuba en route to North Korea when it was stopped by authorities in Panama. Cuba previously claimed the shipment of sugar was a donation for the people of North Korea, however underneath the thousands of sacks authorities discovered military equipment.
Alongside the two supersonic planes, originally produced by the Soviet Union in the late 1950s, officials found two missile radar systems on board.
After arms were found Cuba said they were 'obsolete' and being sent to the Asian country for repair.
The crew on a North Korean vessel 'rioted' when it was seized in Panama according to the president. President Ricardo Martinelli said the ship had sailed from Cuba and tried to illegally smuggle suspected sophisticated missile material through the Panama Canal.
The president described the dramatic scenes on the ship speaking on Radio Panama:
The world needs to sit up and take note: you cannot go around shipping undeclared weapons of war through the Panama Canal.
We had suspected this ship, which was coming from Cuba and headed to North Korea, might have drugs aboard so it was brought into port for search and inspection.
When we started to unload the shipment of sugar we located containers that we believe to be sophisticated missile equipment, and that is not allowed
The captain has tried to commit suicide, and the crew also rioted.
So we are holding this vessel for further investigation.
Cuba is the only one-party Communist regime in the Americas, and a rare ally of also-isolated Pyongyang.
Panama's president has said that authorities have seized a North Korean ship traveling from Cuba with "undeclared military cargo."
President Ricardo Martinelli made the revelation on Twitter and posted a photo of what appeared to be a green tubular object inside some kind of container.
He said: "Panama-flagged ship captured North Korean cargo from Cuba with undeclared military cargo." In a further post he said the, "material came hidden in containers on a cargo of sugar."
A bus crash in Cuba has left sixteen tourist is hospital, including two Britons according to reports.
The bus is believed to have crashed near the city of Cienfuegos as it travelled between Trinidad and Varadero, two major tourist destinations, according to state-run newspaper Cinco de Septiembre.