This article was taken from the September 2011 issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by <span class="Apple-style-span">subscribing online.
Freediving involves diving underwater with just one breath of air -- that is, without an oxygen supply -- to depths of (for the experts) over 100m. For Emma Farrell, a freediving instructor, it's an unparalleled thrill: "It's an incredibly enjoyable way to be underwater." She describes how to hold your breath and learn to freedive safely and effectively.
PREPARE
Take a course; the dangers are obvious. You'll learn to hold your breath and not freak out. "First you'll be taught static apnoea, which is how to hold your breath in water face-down; then dynamic apnoea, which is swimming holding your breath," says Farrell. "The urge to breathe is caused by high levels of carbon dioxide in the blood -- you have to trick yourself into thinking,
'It's uncomfortable, but it's OK.' Breathe gently; then extend the exhalation, this lowers the heart rate, so you're not processing the oxygen as quickly."
DIVE
When you graduate to the sea, you'll start by pulling yourself up and down a line, to make sure you don't get lost. "You then graduate to 'constant weight', where you're just swimming down and back. When you learn with a line, it means you get your technique good enough to maximise your time down there," Farrell says. "You can use a weighted sled to get deeper, but 99 per cent of freedivers don't use them. And you work in an intense buddy system, where on every deep dive you have someone who ascends the last 15-20m with you."
EQUALISE
You have to be able to get rid of the pressure building up in your ears as you descend, by equalising -- otherwise your eardrum could rupture. You need to blow air into your middle ear via the Eustachian tubes at the back of your throat. "There are a number of techniques -- most people do the Valsalva manoeuvre, where you pinch your nose and blow," explains Farrell. "We teach a more specialised technique called the Frenzel, where you use the back of your tongue to push air into the tubes. Say 'cuh' -- it's a cross between that and a swallow."
TRAVEL
Freediving is popular all over the Mediterranean and the Caribbean thanks to their relatively warm, still water. Koh Tao, Thailand, and Dahab, Egypt, are also popular. But don't rule out the UK coastline -- Cornwall offers several great locations, including Newquay, and there many freediving clubs around the country. "It doesn't have to be warm and sunny and gorgeous, though," says Farrell. "Some friends of mine just went to Scandinavia to do freediving under the ice, wearing only wetsuits."
This article was originally published by WIRED UK
