Sebastien Murat

'I hold the world record for swimming nearly 192 metres underwater on a single breath. I'm also going to make another attempt on the world free-diving record [diving without an oxygen tank] later this year. It currently stands at a depth of 171 metres and is held by Pipin Ferreras. He achieved the record in honour of his wife Audrey Mestre, who died in 2002 during her attempt to reach that depth.

I was born in Switzerland and divide my time between Bali and Australia. I'm studying for a post-graduate degree and work part-time as a scuba instructor and underwater consultant for television. My partner, Mikkela, is doing a doctorate at the same university.

I have a four-month-old daughter, Anne-Marie, so I'm up all the time at night. Mikkela is still breast-feeding and my daughter has to feed three to four times a day and through the night, so she'd get no sleep or work done if I didn't help out with the bottle. I'm feeding her at 1am, getting up at 6am, feeding her again at 7am.

By 8am, I'm in the pool training. I live in Townsville in north Queensland because I go to university there. My schedule gives me the time to train for my passion, free diving. The public pool where I train is about a 20-minute drive from where I live. I'll spend half the year training at the pool and the other half out on the ocean.

I don't have breakfast before I train and I wait an hour afterwards before I eat. You can't dive well if you've had a big meal. When I train, I treat every day as if I'm going for a world record. Quite often I go over what I need to break it, although it's just a simulation. A pool's a sterile environment. I simulate what I would do in the ocean. My warm-up is sitting in the water for five minutes getting mentally prepared. Then I submerge and I'll sit on the bottom of the pool doing nothing, which simulates the descent. When I have the urge to breath, usually after about 110 seconds, I'll start swimming lengths of the pool to simulate the ascent. To make life more difficult - because when you are at depth you're negatively buoyant and heavy - I wear a harness with a float attached to cause drag. Instead of taking three or four strokes to cover 25 metres it takes 12. It can't get any harder. You're swimming without air and something's holding you back.

Other people using the pool don't understand what's going on. They see a guy just sitting in the water relaxing. Then he's under the water for three or four minutes and later he shows up and they're, 'Oh, what happened, where did he come from?'

I used to have a big mono-fin that attracted a lot of attention. People would stand on the side of the pool going 'ooh, aah'. I try to be discreet about it, especially with kids, who like to copycat. I leave the pool at 9.30am and head to university. I have to publish a couple of papers before the end of the year.