1. Start inhaling and exhaling slowly
2. Breathe from deep within the diaphragm for last breath
3. As oxygen runs out blood diverted from hands to vital organs
4. At a critical level, could suffer latent hypoxia


Illusionist David Blaine is attempting to break the world record for holding breath under water. But how do you hold your breath for nearly nine minutes?

He is spending seven days underwater in a "human aquarium" using only an air line to breathe, but that is not enough for illusionist David Blaine.

He plans to round off the stunt in New York by attempting to break the world record for holding breath under water - which currently stands at eight minutes, 58 seconds - while trying to escape from 150lb (68kg) of metal chains.

It is a task few professional freedivers think is achievable with the best of conditions, let alone after a week submerged in water, while trying to escape shackles. So how will he do it?

What Blaine is doing is called apnoea, which is the scientific term for breath-holding and literally means "without air". Because he is not descending through water at the same time, it is known as static apnoea.

To hold his breath for such a long time he will need to slow his heartbeat by relaxing, entering a meditative state. With a reduced heart rate the body consumes less oxygen, thereby prolonging the time Blaine can spend underwater.

He has also lost 50lbs (23kg) in weight to improve the efficiency with which his body uses oxygen.

Gulp in

To get the biggest breath he can for the challenge, he should start inhaling and exhaling slowly. This exercise rids the lungs of poor-quality air. For the final inhalation, he should begin slowly, breathing from deep within his diaphragm.

Some freediving experts get a final bit of air by using a technique called "packing". It involves gulping like a fish at the end of the breath to pack in even more oxygen. But it is a dangerous technique and very few people can do it properly, according to the British Freediving Association (BFA).


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As Blaine holds his breath his store of oxygen will reduce and the body will start diverting blood from his hands and feet to his vital organs.

Oxygen will fall to a critical level risking latent hypoxia - more commonly known as shallow water blackout - which is when a person loses consciousness. There are no warning signs, which is why static apnoea should always be done with a partner, says the BFA.

What Blaine does have which is extremely important for static apnoea is highly developed mind control.

"This discipline is a complete mind game," says BFA chairwoman, Emma Farrell. "It is the most psychological of all the freediving disciplines as you have to have a clear mind and stay calm while you are just lying there."

Secret to stunt?

The current record stands at eight minutes, 58 seconds, but freedivers have held their breath for up to 15 minutes by breathing in pure oxygen. That is how the BFA believes Blaine will pull off his stunt.

I think he will actually breathe in pure oxygen through his air line, which will help him hold his breath for longer

Emma Farrell
BFA
"It is simply not possible for him to breathe in air and hold his breath for that long while escaping from chains," says Ms Farrell.

"Static apnoea is all about getting yourself into a deep state of meditation which you can't do while trying to escape from chains, he will have adrenalin pumping through his body.

"To pull off the stunt I think he will actually breathe in pure oxygen through his air line, which will help him hold his breath for longer."

Judges from the International Association for the Development of Apnoea (AIDA) would have to attend Blaine's attempt for any record set to be officially recognised.

Their attendance has not been mentioned by the illusionist, probably because under the AIDA's rules they would have to spend at least two hours with him before his record attempt to make sure he does not breathe in any pure oxygen.

The BFA is sceptical about Blaine's stunt and also concerned that it will encourage people to try and hold their breath underwater without training.

"We have tried hard to change the image of freediving," says Ms Farrell. "People tend to think it's an extreme sport and it's not. Freediving is very safe if you do it properly.

"By turning it into a stunt, David Blaine is sending out the wrong message about freediving and damaging its image."