Man dives 65 feet to test sinking theory. When does your body really sink in ocean?

Ever felt a twinge of fear when you dip into the deep end of a swimming pool? You’re not alone. The thought of sinking, especially in an ocean, can be downright terrifying. Now imagine being 65 feet underwater, where the darkness engulfs you and your body no longer floats but sinks – rapidly. That’s exactly what one man did to demonstrate a fascinating yet unnerving theory about how our bodies behave as we dive deeper into the ocean. And trust me, it’s scaring people out of even thinking about deep diving.

Free-diving, for the uninitiated, is diving underwater without any breathing apparatus – just you, your lungs, and the vast ocean. While that sounds daring enough, the real kicker comes when you realize how much pressure increases as you descend. The deeper you go, the more the water pressure crushes your lungs and forces your body to sink.

A video circulating on Reddit captured the eerie reality of what happens to the human body when it dives deeper. The diver, already submerged, grabs hold of a lifeline rope, posing the question: "At what depth do I start sinking?"



At first, he’s floating comfortably at 16 feet. By 32 feet, he’s still floating but slower. Things start to change at 40 feet – he’s neutrally buoyant, neither rising nor sinking. Then, at 50 feet, his body begins to sink. By 65 feet, gravity takes over, and he sinks fast, proving that even a body that floats easily at the surface will eventually succumb to the deep.

Why? It all boils down to pressure. At sea level, air pressure is equal to 1 bar, or 1 atmosphere. Dive just 10 meters (about 32 feet), and the pressure doubles. This compresses the air in your lungs, making you less buoyant. The deeper you go, the more compressed the air becomes, and the harder it is for your body to stay afloat.

This revelation had Reddit users rethinking their swimming goals. One user admitted, "The older I get, the less enthusiastic I am about this whole free-diving thing." Another joked, “That’s some gnarly stuff. I’m happy being a land mammal.” Others didn’t mince words: "I had no idea this was a thing and I just became slightly more afraid of the ocean."

One commenter wrote, “Imagine the rope fading away while you sink into the dark ocean floor,” while another simply added, “No, I don’t think I will.”