What is POTS, the disease affecting Olympic swimmer Katie Ledecky?

Five-time gold medalist Missy Franklin spoke with Fox News Digital about her expectations for Katie Ledecky ahead of the 2024 Summer Games next month in Paris.

After nearly a decade of keeping it under wraps, Olympic medalist Katie Ledecky has shared her POTS diagnosis with the world.

The athlete, who has won 14 Olympic medals for swimming, the most of any female Olympian, said she has POTS (postural orthostatic tachycardia syndrome).

In "Just Add Water: My Swimming Life," Ledecky's new memoir, which was published by Simon & Schuster in June, she wrote that the disease can cause "dizziness, fainting and exhaustion."

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Here's more. 

POTS is a disturbance in the autonomic nervous system, which controls some of the normal regulatory functions of the body, according to Dr. Blair Grubb, a cardiologist and expert on POTS at The University of Toledo College of Medicine and Life Sciences.

Katie Ledecky competes in the swimming 400m Freestyle Women Heats during the Paris 2024 Olympic Games at La Defense Arena on July 27, 2024. After nearly a decade of keeping it under wraps, Ledecky has shared her POTS diagnosis with the world. (Getty Images)

"When the person stands, gravity will try to displace downward roughly 20% to 30% of the body's blood volume," he told Fox News Digital. 

In response to this displacement, the brain tells the heart to beat faster and more forcibly, and tells the blood vessels in the lower half of the body to tighten, or constrict, to three times the level they were previously, the doctor said.

"This allows for accumulation of much more blood than normal in the lower half of the body," Grubb said.

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