Humans have been free diving—plunging under the water with just a lungful of air—for over 2500 years, and today’s top pros can make it 700 feet deep on a single breath. If you want to explore the deep without a scuba tank, here’s what you’ll need to do.
Technically, if you enjoy dunking your head just a few inches below the waves, you’re already a free diver. Congrats! Of course, if you want to join the world of deep-sea free diving—called competitive apnea—you’ll need more know-how.
Your mammalian diving reflex, that is. When cold water splashes against your face, your body’s physiology changes. The reflex kicks in, making your heart rate sink and your outer blood vessels constrict. It also releases oxygen-rich red blood cells into your bloodstream. Altogether, thanks to the MDR, you can hold your breath longer underwater than you could on land.
The world’s best free divers can hold their breath over 10 minutes. That’s because they know how to deplete loads of CO2 from their bloodstream. Increased concentrations of CO2 encourage the urge to inhale. If you can deplete your bloodstream’s CO2 stock, you’ll be able to stay under longer.
“Breathing up” is one of the best ways to do just that. Practice by timing your breaths, and exhaling for twice as long as you inhale. (If you breathe in for three seconds, breathe out for six.) With practice, this will stabilize your heart rate and remove extra CO2 from your bloodstream.
You’ll need to build up your body’s CO2 tolerance, too. After doing the breathe up exercise for a few minutes, hold your breath and walk as far as you can. When you can walk the length of a football field, you’re ready to free dive.
Get in the water and go for it, starting with baby steps. Go 10 feet until it’s easy. Then shoot for 15 feet. When that’s a cinch, chip your way to 20.
Once you’re below 10 feet, your body will need to adjust to the pressure—your ear especially. Pinch your nose and exhale until you hear a pop. But don’t worry about adjusting on your way back up: your ear will do that on its own.
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You don’t have to take a dive to be more interesting – you can always do that just by raising a cold Dos Equis.