TED talks: Free diving

David Blaine does extreme things that doctors consider imposible. He lived in a cover up coffin one week, he froze herself tree days and tree nights... His next pursuit was see how long he could hold his breath.

He informs about that. He met a top neurosurgeon and he asked him, how long could he go without air? And he said to me that anything over six minutes you have a serious risk of hypoxic brain damage. Also they told him that if he is a magician, he can build up an delusion of not breathing, it will be much easier. David creates a rebreather, but clearly wasn't going to work. Then he thought about the craziest idea of all ideas: to actually do it.

The first thing that he learned is when you're holding your breath, you should never move, because that wastes energy and your heart rate down. Then he learned how hyperventilating because that eliminates CO2 from your blood and that make easy hold your breath. Moreover he starts a diet compoused by small meals.

Afterward of 4 months his heart rate down to 38 and he could hold his breth 7 min. After that, David trys to make slower his heart ratein in extreme conditions due to that he held his breath knot. He lost consciousness and they had to revive.

Finally he decided to do it with pure O2. As well he slept in a hypoxic tent every night. What that does is, you start building up the red bloodcell count in your body,  which helps you carry oxygen bettter. His first attempt on pure O2, I was able to go up to 15 minutes.

For make the tv program he had to tie his foots and do it vertical, because with that way the spector can see David. Normally his hear rate was 38 but in the tv program day his heart rate was 150. After 11 minutes he don't feels his limbs. After 15 min he start to undergo ischemia. However he resist until 17 min 4 s. Finally he reflect about magic and he say that magic is about train and experiment.

I am a amateur of freediving and I can hold my breath 3 min. I am impress about what this man has achieve, but I disagree when he say that he has to learn how hyperventilating. Hiperventilating eliminates CO2, that is true, but so many freedivers don't recommend it because it speed up the syncope and that increments the riskiness.