Anyone who has held their breath underwater has freedived.

For thousands of years people have freedived for pearls or simply for food. Freediving has particular importance for Abu Dhabi where pearls brought wealth to the region before oil. So how do freedivers manage to hold their breath for so long and dive so deep?

Like diving mammals, humans have a dive reflex (the Mammalian Dive Reflex) which helps to conserve oxygen. Our bodies achieve this by restricting the flow of blood to the extremities (arms and legs) and slowing our heart rate down. Amazingly freedivers have reported a 50% drop in their heart rates during a dive.

Along with intensive training, the dive reflex has allowed freedivers to descend to depths of over 200 metres on a single breath hold. But how do their bodies cope with this depth? For years, doctors believed that our lungs would collapse if we descended further than around 30 metres. But freedivers proved them wrong. It was found that at depth, our blood shifts into the blood vessels around the lungs to compensate for the reduced lung volume allowing divers to go deeper.

However there is still much to learn about freediving. The surface breath-hold world record is over 11 minutes - but it takes less than 4 minutes to get to 200 metres and back - so where will it end? This is one of the attractions of freediving, it is a young sport and there is still a lot to be discovered.