The Impossible Physiology of the Free Diver

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descent

descent

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The amazing underwater athletes are rewriting the science of the body.

By Adam Piore
March 26, 2015​


In 2011, Hanli Prinsloo decided she wanted to break the woman’s world record in free diving. She would need to dive to 213 feet below the surface of the Mediterranean Sea and hold her breath for about four minutes. Until the 1960s, scientists believed it was not humanly possible. The increased water pressure at that depth, they argued, would crush her lungs.

The then-33-year-old, South African, former acting student knew the feat would require rigorous training and commitment. But Prinsloo felt at home in the water. She’d grown up on a dusty, 200-hectare horse farm outside Pretoria, chasing her sister from dam to stream to swimming pool and back and dreaming of becoming a mermaid. So in the spring of 2011, Prinsloo packed a bag and traveled to an ashram in the foothills of the Indian Himalayas. She spent a month meditating and practicing Vinyasa Yoga.

After six weeks, it was off to Dahab, Egypt, an isolated Bedouin Village hemmed in on one side by the Red Sea, and the Sinai Mountains on the others. On dive days, Prinsloo and fellow diver Yaniv Keinan hopped in a 4x4 and bounced past tourists on camels down a rutted desert track until they reached the water. They waded 50 feet through knee-high water out to the edge of a sinkhole, about 400 feet deep, known as the “Blue Hole.” .... (read more (3400 words))
 
Thanks for posting this. Good article - it is a relatively easy read that sums up the major physiological factors in freediving.

There are a few practical things to be aware of that the article doesn't cover but that is not surprising as those practical things are things to avoid doing once you get deeper and are the sort of thing covered in an advanced freediving course.
 
Thanks, I found it fascinating.

I have no freediving experience beyond a few sixty or ninety second snorkel dips. My guide said, "Don't stay down so long. It's upsetting. We don't want a rescue."

I have always wanted to try a dive that required some commitment, training and preparation.
 
Many people dismiss free diving as being an "extreme sport". While it has some risk associated with it I believe this risk can be managed well if you are doing it with the right people and in the right way.

I am not a competitive free diver but I have joined a free diving club (a little over 18 months ago), learnt heaps and had fun. My free diving has now progressed to the point where all the physiological changes mentioned in the article will happen on a deeper dive and there are practical things to be aware of to avoid injury. E.g. while blood shift happens as the lungs compress we still need to be careful that we don't damage our lungs and trachea.

At 40m / 130ft / 5 bar lungs are 1/5th the size they were at the surface, blood shift has kicked in but they can still be damaged by movements that stretch the chest cavity or move the trachea / throat much. This means that we avoid much arm/shoulder movement and head movement. Interestingly the more you dive the sooner the dive reflex kicks in and the more flexible your chest becomes so things get easier (a little).

---------- Post added March 28th, 2015 at 03:57 PM ----------
descent:
I have always wanted to try a dive that required some commitment, training and preparation.
Click to expand...

At the free diving club I belong to we have two training groups with different targets and also have a culture of not progressing too quickly, celebrating everyones achievements and generally having fun. We have two training groups running at the moment - each with a different set of goals (and no time pressure on achieving those goals).

734 Club goals are:
* 7 = 75m Dynamic i.e. 75m in a pool on one breath (your choice of with or without fins)
* 3 = 30m Constant Weight i.e. 30m down and back (either with fins, without fins)
* 4 = 4 minute static i.e. 4 minute breathhold in the pool

Each of these requires slightly different stuff and some will find one discipline harder than another

The other group is 145:
* 1 = 100m dynamic
* 4 = 40m Constant Weight (depth)
* 5 = 5 minute static breathhold

So far 12 of us have completed the 145 goals - it took me almost a year to get there and I started from quite a good base having spent several years spearfishing (free diving) and also playing underwater hockey and underwater rugby so I had a relatively high tolerance to CO2 and was comfortable holding my breath at a reasonable depth (diving to 25m when I joined the club not too long ago). It is interesting how these goals have motivated people to train.

HOWEVER free diving is not all about the numbers - it is more about getting in the right mental state, with the right safety protocols and people in place and then seeing how you go.
 
I found a nice article about freediving for world records in the New Yorker magazine.


   The Deepest Dive: How far down can a freediver go? August 24, 2009

   by Alec Wilkinson
   August 24, 2009


... The most prestigious discipline is constant weight—the diver must return to the surface with the weight that he or she wore to descend.

The women’s record for constant weight is ninety-six metres, which took three minutes and thirty-four seconds. (The men’s record is a hundred and twenty-two metres.) For women, a hundred metres is a barrier something like the four-minute mile used to be, and the diver who is the first to accomplish the feat will have a prominent place in the annals of the sport.

Only two women are thought to be capable of it. One is Sara Campbell, a British diver who lives in Egypt, and the other is Natalia Molchanova, a Russian who lives in Moscow.

Campbell set the record of ninety-six metres in April, in the Bahamas, breaking Molchanova’s record of ninety-five, which had broken Campbell’s record of ninety. Five days after Campbell reached ninety-six metres, she dived to a hundred, returned to the surface, took two breaths, and passed out. (A safety diver caught her.) The rules governing record dives require that a diver remain conscious for sixty seconds after surfacing, so Campbell’s dive was nullified. ... (more)
 
Another interesting read.

The womens world record for CWT (constant weigh with fins) is now 101m and held by Natalia Molchanova. In fact she now holds all womens world records except for the No Limits one. No Limits is not something that is done often. Many AIDA members are considering no longer recognising No Limits attempts (or at least not actively promoting them)

Here are the world records from AIDA: https://www.aidainternational.org/competitive/worlds-records

My impression is that the top freedivers have a much more safety conscious culture than that portrayed in the article (but I am only going on discussions with a couple of the top guys and observations of forum posts and competition reports).
 
Classic movie! Although neither of them reached 400ft (122m) in real life - and they were doing No Limits diving ...

The current world record for Constant Weight with Fins is 128m (420ft) so reality has caught up and surpassed dramatisation / fiction.
 
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