We *Are* Aquatic Mammals

August 25, 2014 9:28 AM

This Is What Happens To Your Heart When You Dive Into The Sea

Human blood has a chemical composition 98% similar to seawater. An infant will reflexively breaststroke when placed underwater and can comfortably hold his breath for about 40 seconds, longer than many adults. We lose this ability only when we learn how to walk.

posted by dame (38 comments total)

You simply need to get wet.
Specifically, the face.
posted by the man of twists and turns at 9:40 AM on August 25, 2014

The eye evolved underwater. It then had to adapt to air, and still has weaknesses that underwater eyes don't. A very short-sighted person can see more or less normally under water. People can be trained to have excellent eyesight under water (Thailand's Moken people).
posted by stbalbach at 9:46 AM on August 25, 2014 [5 favorites]

Buzzfeed Books?!?!?!?!? Between this and the far more frequent references to Buzzfeed here, I starting to wonder if we are we witnessing the slow ascent of a creature out of the primordial What Kind of Kitten Are You? ooze to to stand on quivering legs among the behemoths of The NYT and The Atlantic (or at least scamper through the underbrush with the likes of Cracked and Slate)?
posted by rtimmel at 9:55 AM on August 25, 2014 [18 favorites]

This really seems like a modified, non-sourced Aquatic Ape hypothesis.

...which is not a compliment.
posted by aramaic at 10:03 AM on August 25, 2014 [12 favorites]

rtimmel, I actually think Buzzfeed is brilliant for harnessing click-baitery for goodness. They are the only online journalism source with a real, Internet-savvy revenue model and they use it to fund in-depth journalism and to hire amazing writers like Anne Helen Peterson. That's why they just raised a whole shit-ton of new venture capital, too.
posted by dame at 10:03 AM on August 25, 2014 [4 favorites]

Jesus, all those words and a glaring typo in the second-to-last sentence.
posted by saladin at 10:08 AM on August 25, 2014

While the whole idea of not having to swim against the human body's buoyant force sounds interesting and empowering it is more than countered by the knowledge that I'd have to swim back up against the, now very real, pull of gravity if I, ya'know, wanted to refresh my oxygen supply.

It's almost always fun to read about skin divers, free divers, cave divers, and the lot but, even after having done a 1+ hour scuba intro in Central America, it's one of those things I'll most likely limit myself to reading about instead of doing.
posted by RolandOfEld at 10:12 AM on August 25, 2014 [3 favorites]

Jesus, all those words and a glaring typo in the second-to-last sentence.

Well...he did type the whole thing on a single free dive to 700ft.
posted by yoink at 10:17 AM on August 25, 2014 [1 favorite]

aramaic, I would be interested to know what you mean. I will say I love this because I love water and, like most swimmers, dream of being able to go all the way down sometime. And recognize in myself that special change that happens when I get in the water.
posted by dame at 10:19 AM on August 25, 2014 [1 favorite]

It's almost always fun to read about skin divers, free divers, cave divers, and the lot

I think you misspelled terrifying there.
posted by jeather at 10:19 AM on August 25, 2014 [2 favorites]

I didn't know about the negative buoyancy once you dive deep enough, which is terrifying holy shit
posted by tiaz at 10:23 AM on August 25, 2014 [4 favorites]

Reading about free diving always makes me hold my breath, and I almost never notice I'm doing it until I have to gasp for air.

On the rare occasions I've gone swimming here in Northern California, I have not noticed this relaxing feeling of my body remembering how to be in the ocean - I notice how freaking cold the water is. Last year, though, back in Hawaii for the first time in a long time, it was wonderful to be back in such welcoming water.
posted by rtha at 10:39 AM on August 25, 2014

Freedivers can totally get decompression sickness. Not over the course of a single dive, but if you're making multiple deep dives, you still accumulate high levels of nitrogen.
posted by fnerg at 10:44 AM on August 25, 2014

Hmmmm. When I see anyone use a term like "renegade science," I think "hmmmm."

I also haven't particularly noticed Buddhist monks having "glassy eyes," but maybe that's just me.
posted by GenjiandProust at 10:44 AM on August 25, 2014

What Kind of Kitten Are You?

I think I was a Scottish fold. I think. I have to retake that one. I'll keep you all updated.
posted by discopolo at 10:45 AM on August 25, 2014 [3 favorites]

A very short-sighted person can see more or less normally under water.

I can assure you this is not a universal truth.
posted by deludingmyself at 10:57 AM on August 25, 2014 [6 favorites]

I found the article fascinating - I've watched a few shows about free divers but I didn't know a lot of the facts here.

Side note, as someone who has lived my whole life on the northern half of the West Coast, reading about swimming comfortably in the ocean always reads like science fiction to me. Like, I can't even imagine what that's like. People who can do this, why aren't you in the ocean RIGHT NOW? I would never leave the water.
posted by peep at 10:59 AM on August 25, 2014 [6 favorites]

The ocean not only changes us physically, but psychically.

I also want to point out that this is clearly disguised propaganda from the Esoteric Order of Dagon. I mean, I am all for worshiping hideous beings from beyond space and time, but let's try and keep some sense of proportion.
posted by GenjiandProust at 11:03 AM on August 25, 2014 [3 favorites]

As you keep diving, at about 40 feet, you enter a gravityless area in the water column that freedivers call the “doorway to the deep.” Here, the ocean stops pulling you up the surface and begins pulling you down.

Well fuck no
posted by logicpunk at 11:19 AM on August 25, 2014 [16 favorites]

but let's try and keep some sense of proportion.

That's why you need to go underwater. You'll see better.

Down where it's wetter.

Take it from me.
posted by curious nu at 11:20 AM on August 25, 2014 [10 favorites]

I would never leave the water.

Eventually you have to pee.
posted by elizardbits at 11:40 AM on August 25, 2014 [4 favorites]

Nah, you can pee in the sea. Fish do it! But eventually you get cold, even when it is warm-ish. (Though I grew up on the lower half of the West Coast and while swimmable it isn't exactly bath-y, y'know?)

Also! If scuba scares you, don't give up! It makes me totally claustro but I still love the sea. I just don't wear tanks in and snorkel more often.
posted by dame at 11:46 AM on August 25, 2014

I really loved this article being a fan of snorkeling and relaxing in the water. The article really describes how well we can be connected to the sea as humans.
posted by Meatafoecure at 12:01 PM on August 25, 2014

The ocean is the last truly quiet place on Earth.

If only.
posted by nicodine at 12:15 PM on August 25, 2014 [3 favorites]

I really *want* to believe this, it sounds lovely, but I find it hard to believe - there's just enough woo in there that I get skeptical.

"An infant will reflexively breaststroke when placed underwater and can comfortably hold his breath for about 40 seconds, longer than many adults. We lose this ability only when we learn how to walk."
Just leaves me asking - source?
posted by Joh at 12:17 PM on August 25, 2014 [1 favorite]

Nah, you can pee in the sea.

This sent me into an impossible calculations spiral of wondering how many adult average-sized humans would have to pee simultaneously into the sea before the water levels registered as even a miniscule barely detectable percentage of pee.

thus far my calculations have led to "a whole fucking lot"
posted by elizardbits at 12:21 PM on August 25, 2014 [3 favorites]

For me the 'this is woo' feeling kicked in at the 20" chest measurement. I don't think so. Pics or it didn't happen. Hard to take any of it seriously after that.
posted by glasseyes at 12:37 PM on August 25, 2014

It's not hard to google Francisco Ferreras-Rodriguez and see that the 20-inch chest claim is widely repeated, although it appears to be the result of calculation rather than observation.
posted by localroger at 12:56 PM on August 25, 2014

I do love the water and I do want to try diving some day. Part of me is totally terrified to do it though. My cousin, at age 19, who was a water baby and studying ocean biology died while diving. She had some sort of aneurysm. It was just a relatively shallow and fun dive and after giving her partner a thumbs up that she was ready to surface just never appeared.

I know it's rare and a freak thing to happen but I'm afraid of being super paranoid about it and it ruining the experience. I suppose it's something I'll just have to get over if I ever want to do it. Sucks though.
posted by Jalliah at 1:16 PM on August 25, 2014

"An infant will reflexively breaststroke when placed underwater and can comfortably hold his breath for about 40 seconds, longer than many adults. We lose this ability only when we learn how to walk."
Just leaves me asking - source?

No source, just anecdata, but that is what they tell you at baby-swim classes, and they also say that if you go to those classes, your baby will keep that ability. I haven't asked her how she does now, but my daughter was comfortable with very long dives even when she was a pre-schooler, often scaring the wits out of me, a mediocre swimmer.

That said, the article seems wooish to me.
posted by mumimor at 1:51 PM on August 25, 2014 [2 favorites]

Babies have a number of reflexes, such as the Moro and walking reflexes, which are very repeatable and which reliably disappear as we age. The swim reflex is well documented.
posted by localroger at 2:43 PM on August 25, 2014

Also, for those who are freaked out by all this, the other thing you will learn if you google Francisco Ferreras-Rodriguez is that he lost his wife when she failed in an attempt to beat the world freediving depth record.
posted by localroger at 2:46 PM on August 25, 2014 [1 favorite]

Oh, I just got out my tape measure and looked at 20" round. You couldn't force long ribs into that shape.
posted by glasseyes at 4:52 PM on August 25, 2014

Taking advantage of the mammalian dive reflex was recommend to me by a Dr to stop a fast heart rate due to Supraventricular Tachycardia. Once my wife stuck an ice pack on my face once during an event and my HR went back to normal like flipping a switch.

After reading this, I'm excited to try monitoring my HR while sticking my face into cold water and see just how much of an effect it has.

(I assume that my chest will stay normal sized)
posted by kevin is... at 5:01 PM on August 25, 2014

Oh, I just got out my tape measure and looked at 20" round.

I suspect that whoever did the original calculation didn't take into account that the compression would be more in the form of flattening than shrinkage while maintaining proportion. Still seems very dramatic, but corsetry has achieved some almost equally dramatic changes in proportion without killing people.
posted by localroger at 5:18 PM on August 25, 2014

"All the stress, noise, and distractions of life are left at the surface."

I've always maintained that no matter how hot it gets or what the calendar says, it's not summer until your first plunge into the sea. And if you're lucky, after you've jumped in and are still underwater, right at that time when gravity and buoyancy are evenly matched, you can experience for a moment actual bliss.
posted by hoca efendi at 6:22 PM on August 25, 2014

Scientists witnessed that these animals seem to gain oxygen the deeper and longer they dive; according to our understanding of physics and mammal physiology, this is impossible. And yet these animals do it all the time. And still, nobody quite understand how. (Again, the ocean has different rules, requires a different mind-set to comprehend.)

Here comes the crank train. Woo woo!
posted by Joe in Australia at 10:15 PM on August 25, 2014 [4 favorites]

Thanks a man of twists and turns, no more drunk free diving for me! I like the idea of the article, there is a lot of interesting science around this subject, but I don't think the author has read much on it. There are a lot of weird claims in this article, e.g. The human body reflexively processes the uptake of dangerous gases that occur at depth; we’ve known how to do this for, perhaps, millions of years.

Nevertheless, if swimming in the sea is your thing then go for it! Just look after the inhabitants of the oceans, it is not a fun park for humans.

Vis a vis the chest diameter question:

The blood shunted from a diver's extremities by vasoconstriction travels to organs in his chest cavity, occupying the space created when air in the lungs compresses. Most importantly, blood travels to the alveoli, tiny sacs in a diver's lungs where gas exchange occurs. The alveoli are engulfed in blood plasma from the surrounding tissues. As blood is (for our intents and purposes) an incompressible fluid, it maintains its volume no matter how deeply the diver descends. Because fluid replaces the empty space left behind when air in the diver's lungs compresses, his chest and lungs are not crushed by the increased pressure of the water.

It is an oversimplification to talk about the lungs being compressed to the size of apples, or grapes, or whatever, as once the limits of chest compression and diaphragm flexibility are reached during the descent, the lungs do not actually shrink much more. The limits of chest compression and diaphragm flexibility prevent it. Probably if the whole lungs were squashed to the size of apples, blood flow in the lungs would be squashed as well. Contrarily, blood shift relieves some of the pressure on the chest while still allowing adequate blood flow through the lungs and heart.

posted by asok at 6:04 AM on August 26, 2014 [1 favorite]