How long can you hold your breath for? Some free divers, who swim without a snorkel or scuba gear, can hold their breath for more than 10 minutes. For some, it's a recreation while for others it's a competitive sport. Amanda Smith (who can only hold her breath for one minute) takes a look.

I'm at a motel swimming pool in Rye, on the Mornington Peninsula in Victoria. Freediving instructor Marlon Quinn is taking a weekend workshop for a group of four men and two women. Tomorrow they'll head out into the open sea, but today they're learning breath-holding techniques in the pool.

According to Quinn, it's important to find a state of relaxation before you dive.

When you're doing deep diving you might be able to see 40 or 50 metres and there's not really any sound.The only thing you probably will be hearing is your heartbeat. It feels like time has stopped. Jody Fisher, free diver

'The struggle for a lot of people coming to free diving is, “How do I find the sense of calm? How do I find the ability to be comfortable with something that I may fear?”

‘You'll only find the positive by understanding the negative. If you can overcome those urges of wanting to breathe, if you find the relaxed state early and you're able to take that into the free dive, then you actually have a longer, nicer phase of your breath hold.'

Quinn is trying to get each person in the group to understand what it is that triggers their first urge to breathe. For some it will be mental chatter telling them they need to inhale. For others it will be a physical response such as a tightening of the throat.

The men and women in this group have signed up to learn these underwater breath-holding techniques for a variety of reasons. James is a spear fisherman, and hopes that by being able to stay underwater longer on a single breath he'll be able to dive deeper and spear bigger fish.

Arthur is interested in yoga, particularly the breathing exercises known as pranayama. Olivia works for a local company that takes people out swimming with dolphins. Being able to hold her breath underwater for longer will be useful.

'You've got to be able to stay down and play with the dolphins for at least a couple of minutes, keep them around, keep the guests entertained and the dolphins at the same time,' she says.

Free diving is also a competitive sport. There are various disciplines, which include actively swimming and staying still underwater. In the open sea, it's about diving for depth in a single breath; the top divers descend more than 100 metres.

'I have an underwater working time of about three to three and a half minutes,' says Adelaide-based Jody Fisher, the only Australia to date to have held a world title in free diving.

How long can she hold her breath when she's not swimming?

'I've never really taken that discipline which is called 'static apnoea' very seriously, but about six and a half minutes'.

To me this seems like an extraordinary amount of time, but Fisher says it's not especially impressive. The current men's world record holder is Stephane Mifsud of France with a time of 11 minutes and 35 seconds and the womens' world record is held by Natalia Molchanova of Russia with a static breath hold of just over nine minutes.

When you hold your breath, carbon dioxide levels in your body start to rise. After that, in what free divers called ‘the struggle phase’, you get the urge to breathe. As more time goes on, the oxygen levels in your body begin to fall.

‘It's really important to note that we have these amazing reflexes in our body that make sure that we still have high levels of oxygen in our brain and in our heart and all those vital organs that might be susceptible to oxygen damage,’ says Fisher.

‘As your heart-rate slows down, all your metabolic processes slow down and you get this movement of all the blood to your core and your vital organs. Your muscles stop working aerobically, so you get a lot of lactic acid, but they're not actually using any of that vital oxygen that's in your body. That's why we don't hurt ourselves by doing this sport.'

Fisher does add a warning, however.

'This is a sport where everyone is highly trained and we have extremely rigorous safety protocols, because there is always the risk that you hold your breath for too long. If you don't have the right protocols, if you're not there with a buddy, this is extremely dangerous, so please don't just rush out and do this. Contact the relevant experts and get involved with it that way, and then you can do it safely.'

Marlon Quinn also emphasises safety in his free diving instruction.

'If you don't manage the risks then it becomes dangerous. You have to know the signs of difficulty and how to rescue someone.'

And never do it alone: 'Always free dive with a buddy', says Quinn.

The art of breathing Sunday 22 February 2015 Listen to the Body Sphere's program about virtuoso breathing in, breathing out, and holding your breath. More This [series episode segment] has image, and transcript

Fisher describes diving underwater without artificial breathing equipment as a magical experience.

'When we hold our breath, our biorhythms and our normal sense of the passage of time gets interrupted,’ she says. ‘This is because we sense the passage of time linked with breathing and also our heart-rate.

‘When you're free diving, as soon as you start holding your breath and your heart rate starts to drop, it feels like everything around you is slowing down. When you're doing deep diving you might be able to see 40 or 50 metres and there's not really any sound.The only thing you probably will be hearing is your heartbeat. It feels like time has stopped.’

Editor's note: This article has been updated to reflect the importance of safety procedures when free diving (26/02/2015)

Focusing on the physical, The Body Sphere is about the ways we use our bodies to create and compete, nurture and abuse, display and conceal.