The Dangers of Free Diving | Science of Stupid: Ridiculous Fails

And now, we briefly interrupt our critique of the extra silly to salute someone extra special.

Now, if I suggested a sport that literally drained your body of life sustaining oxygen, edging you to the very brink of existence, you'd probably say, no thanks. But then you're not Alessia Zecchini, aiming to dive deeper on one breath than any female freediver has before in her category.

[plop] Even at the surface, the average person runs out of breath after little more than a minute, but Alessia is far from average.

[music playing] And down at 351 feet, almost the length of a football field, she breaks the record, surfacing after a single breath hold of 3 and 1/2 minutes.

[cheering] It's easy to forget how dangerous swimming under water can be. It can feel tranquil, almost womb like,

[thud] until you hit a problem, which in free diving can result in oxygen starvation, nitrogen narcosis, decompression sickness, blackout, all the bad stuff.

But while I wouldn't advise trying to beat Alessia's record, I would recommend learning the science behind the feat. As our freediver dives, his body consumes its oxygen supply, which can lead to a potentially lethal blackout.

In his favor is an evolutionary response called "the mammalian dive reflex," which diverts oxygen-rich blood to the vital organs and reduces the heart rate, lowering oxygen consumption. Efficient monofin technique also helps. Its large surface area displaces a lot of water, propelling him forwards with minimal effort, thereby conserving oxygen.

OK, nearly ready to break some records? It's time for a quick kit check. Flippers work on the same principle as monofins, displacing water to generate propulsion.

[splash] Not so good on land, though. All right, let's dive down where the mammalian dive reflex kicks in, even at shallow depths.

[music playing] Not exactly what I meant by mammalian dive reflex. And while they'll still be experiencing the reflex, they're rather wasting its oxygen-conserving effects.

That's better. Making the most of the propulsion generated by his flippers with gentle rhythmic kicks, conserving precious oxygen for the swim back up, or for riding a bike.

OK, let's head up, but calmly and oxygen efficiently so as to avoid that thing all free divers fear. I was actually thinking of "blacking out," but on that evidence, I think we should leave Alessia's record well alone.