This is from 2021:
"The intensity of the routines and the long stretches that swimmers must hold their breath for has resulted in some athletes passing out during performances.
Swimming’s global governing body, FINA, now warns in its judging manual that artistic swimmers who hold their breaths for more than 45 seconds risk hypoxia.
Though the sport focuses less on breath holding skills than it once did, swimmers still spend a significant chunk of their performances below the surface. The Australian team, for example, is underwater for a total of 2 minutes and 20 seconds of their 4-minute routine, Thompson says.
In June, U.S. artistic swimmer Anita Alvarez briefly lost consciousness at the end of her duet routine during the Olympic qualifier in Barcelona.
After spotting the 24-year-old slipping beneath the surface, coach Andrea Fuentes yanked her mask down and dove, fully clothed, into the pool to rescue her.
Alvarez, who has undergone a battery of medical tests since then, says she still doesn’t know exactly why she fainted that day. But she suspects it was a mixture of physical and emotional exhaustion, plus the specific movements at the end of the routine."
https://abcnews.go.com/Sports/wireStory/brutal-beauty-artistic-swimming-tokyos-toughest-sport-79202516