Man Jumps Into World's Largest Underwater Sinkhole - With NO Scuba Gear
Sometimes people really are amazing. Sometimes they almost scare you. Sometimes, they do both. That's definitely the case with Guillaume (pronounced Gee-yom) Nery, a French freediver with a penchant for breaking records.
Freedivers, for those unaware, plummet to underwater depths with only minimal equipment, usually a wetsuit and a pair of goggles. No scuba gear, no snorkel, no nothing - just lungs full of air, an iron will, and a massive set of cojones.
Guillaume is particularly ballsy, as he tackles this massive 663 foot deep sinkhole in the Bahamas, called 'Dean's Blue Hole' - which is recognized as the largest sinkhole in the world.
A couple helpful little factoids to aid you in understanding the gravitas of Guillaume's dive. The average human being can hold their breath for 45 seconds - or a minute if they have an exceptionally healthy set of lungs. After that, your body essentially starts to suffocate, as cells in your organs shut down from lack of oxygen. Typically, this is when your body initiates panic mode, and will automatically try and thrust you to the surface.
Rapid changes in pressure also affect the brain and bloodflow - too quick a descent can cause blackouts, bloody noses or popped eardrums. Anyone who has dived into a ten foot pool will tell you, you definitely feel a change in pressure at the bottom. At a depth of 663 feet (which is just the depth of the whole, not the full dive) there's a pressure of 287 psi. To give you some frame of reference - normal tire pressure (which holds up your entire car, which may weigh in at over 2 tons) is around 44 - 50 psi.
Guillaume swims to the bottom of the sinkhole and back up with a single lung-full of air. Extensive training helps freedivers condition their lungs, which increases surface area and allows them to hold more oxygen, and have better control over natural panic responses for long periods of time underwater. His entire voyage takes him an astounding four minutes. During that time he swims to the bottom of the hole, sits, and -climbs- back up the sinkhole.
It's worth mentioning that any activity at all - swimming, climbing or even just sitting while under that pressure causes your body to metabolize oxygen even faster - which means that him holding his breath for a whole four minutes while active is more like a normal human being holding their breath underwater for a much longer period of time, while simply doing nothing!
Anyway - the video is REALLY awesome. Check it out, and leave your comments and thoughts below.
For more thrilling freedives, check out Guillaume's upcoming film NARCOSE.