US swimmer rescued from World Championship pool after fainting

Artistic swimmer Anita Alvarez was dramatically rescued from the bottom of the pool by her coach after fainting at the World Aquatics Championships in Budapest.

Andrea Fuentes leapt in to rescue Team USA's Alvarez, who had sunk to the bottom of the pool and was not breathing after completing her routine during Wednesday night's solo free final.

"It was a big scare. I had to jump in because the lifeguards weren't doing it," Fuentes was reported as saying by Spanish newspaper Marca.

Fuentes, dressed in shorts and a T-shirt, dived to the bottom of the pool and dragged Alvarez to the surface before being assisted to get the stricken swimmer to the edge of the pool.

"I was scared because I saw she wasn't breathing, but now she is doing very well," said Fuentes.

Alvarez was taken on a stretcher to the pool's medical centre, with teammates and fans appearing to be in shock poolside.

The US swim team later released a statement saying that Alvarez was doing well.

Fuentes, a four-time Olympic medallist, told Spanish radio that Alvarez had fainted due to the effort expended during the routine.

"She only had water in her lungs, once she started breathing again everything was OK," said Fuentes.

"It felt like a whole hour. I said things weren't right, I was shouting at the lifeguards to get into the water, but they didn't catch what I said or they didn't understand.

"She wasn't breathing ... I went as quickly as I could, as if it were an Olympic final."

Fuentes said Alvarez planned to rest Thursday and was still hoping to compete in Friday's team event after further medical checks.

The 25-year-old Alvarez was in her third World Championships. She also reportedly fainted during an Olympic qualifier in Barcelona last year.