Diver holds his breath underwater for over 29 minutes to set new world record

Croatian freediver Vitomir Maričić has set a world record for the longest time spent holding his breath underwater.

Maričić spent 29 minutes and three seconds submerged in water on a single breath, reports Daily Mail.

That set the Guinness World Record for the "longest time breath held voluntarily underwater", smashing the previous record by almost five minutes.

On 14 June, he laid down in a three-metre pool inside the Bristol Hotel in Opatija, Croatia, in front of five official judges and some 100 spectators.

Before trying to hold his breath, he used a tank of pure oxygen to undergo a process called denitrogenation. 

Maričić used pure oxygen to purge his blood of excess nitrogen. He breathed pure oxygen for 10 minutes before holding his breath, bringing his blood oxygen levels to five times the normal limit. 

Typically, the lungs of a healthy adult hold about 450ml of usable oxygen because oxygen only makes up about 21% of the air we breathe.

Breathing pure oxygen means that the lungs can take in around three litres of oxygen with every breath, washing nitrogen out of the blood and supercharging it with oxygen.

That not only filled his red blood cells with as much oxygen as possible, but also dissolved oxygen into his blood plasma - something that cannot happen under normal circumstances.  

In a medical setting, doctors might use this technique to expand an unconscious patient's 'safe apnea time' -- the amount of time someone can safely go without breathing.

Maričić used the same principle to massively enhance his ability to hold his breath.

However, even with the assistance of pure oxygen, holding your breath for half an hour is still a major achievement.