The Secrets of Freediving: How Divers Defy the Depths of the Sea
The vast, dark depths of the sea continue to harbor mysteries that have eluded mankind for centuries. Among these is the art of freediving—a skill that pushes the boundaries of human endurance. Unlike traditional scuba diving, freediver rely solely on their breath, holding it for up to 10 minutes as they descend into the ocean’s depths before resurfacing.
A viral Reddit video has recently brought attention to the physics behind this extreme sport, revealing just how deep divers can go before nature takes over. The freediver featured in the video explains a fascinating and chilling truth: there’s a point in the sea where the pressure becomes so great that humans can no longer return to the surface unaided.
The pressure of the deep sea
As divers venture deeper into the ocean, the water’s pressure increases, having profound effects on the human body. The Reddit video showcases the freediver holding a lifeline rope at various depths to demonstrate how this pressure affects buoyancy and descent.
At 16 feet underwater, the diver remains buoyant, easily floating back to the surface. Not much changes at 32 feet, though the effort to rise becomes slightly more noticeable. By the time he reaches 40 feet, he becomes “perfectly neutral,” meaning he neither rises nor sinks.
However, at 50 feet, the situation changes. The diver begins to sink, and by 65 feet, the rate of descent accelerates. The deeper he goes, the more difficult it becomes to fight the pull of the sea.
How increasing pressure impacts the body
In an article for The Conversation published in 2018, Dr. Kevin Fong explained how pressure affects the human body during deep-sea dives. “The increasing pressure can manipulate your body, your anatomy, and your physiology in quite profound ways, which actually make the endeavor of diving into the deep ocean uniquely difficult,” Fong wrote.
He elaborated on the concept of pressure, stating, “If you descend only 10 meters into the ocean, you are subjected to another additional atmosphere of pressure: that’s twice as much pressure as you’ve been used to at the surface. And for every 10 meters beyond, you get another atmosphere of pressure.”
This pressure, he explained, not only compresses the air-containing spaces in the body but also alters the way gases act in the bloodstream and nervous system. These physiological changes are what make deep-sea diving so dangerous and challenging.
Breaking the limits of freediving
Fong noted that, historically, physiologists believed humans couldn’t dive beyond 30 or 40 meters. However, freedivers have consistently proven these limits wrong. “Free divers decided to do it anyway—and they swam well past those theoretical limits,” he said.
Despite the risks, freedivers continue to push the boundaries of what the human body can endure underwater. As this viral video demonstrates, the ocean is not only a mysterious place but also one that demands respect, as it holds power over the human body in ways we are still striving to understand.