Public swimming pools across the country are banning prolonged breath holding due to condition called hypoxic blackout, or shallow water blackout, which can lead to drowning. It's a topic AB first explored in 2006.
Shallow water blackout happens when a person attempts to swim underwater for an extended amount of time, typically to build endurance. In order to go a long distance underwater, swimmers will often take several deep breaths, which causes the levels of carbon dioxide in the blood to fall. Once the swimmer is underwater, the carbon dioxide levels don’t rise quickly enough to signal the brain to breathe, oxygen levels go down, and the swimmer faints underwater and drowns.
In a public service announcement regarding the issue, a doctor says, “Because the swimmer has a low oxygen level at the time of the fainting, brain damage occurs within a couple of minutes, and death is very likely.”
The first major cities to ban prolonged breath holding in public pools are New York City and Santa Barbara, California. The bans come after several people died in breath holding incidents in each city.
Those who have died have all been experienced swimmers, with several being military personnel.
Critics of the bans say that they won’t be effective because it is almost impossible for lifeguards at busy pools to realize that the behavior is happening.
However, the manager of Santa Barbara’s parks and recreation department Rich Hanna says that Santa Barbara lifeguards have stopped the behavior twice in the last year.
According to a company spokesman for The Redwoods Group, which insures about half of the YMCAs in the United States, it is better for lifeguards to try to stop the breath holding behavior before it leads to a swimmer becoming unconscious.
“It’s difficult, but lifeguards have a better chance at preventing it than finding it after it happens. Drowning victims don’t yell for help, they don’t splash, they don’t look like they do on TV. They just kind of silently slip underwater.”