Thursday, July 25, 2024
HomeFreedivingThe Later Volumes of Freediving

The Later Volumes of Freediving

Hypoxic tents have arrived in the freediving world. It’s no secret (is it ? I hope I’m not letting the cat out of the bag !) that a number of the world’s top competitors are sleeping at 3, 000 meters’ altitude or more, this in the comfort of their sea-level homes.  Adaptation to an oxygen – poor environment: hemoglobin, RBC and hematocrit on the rise, neovascularization, myoglobin muscle mania. You pitch this tent in your house, see, and dial up an altitude. You close yourself inside, and the conditioning unit maintains the inside air at the equivalent density  of the selected altitude. Even while you’re sleeping, you’re working out. Maintaining a positive altitude at all times.

Pretty hard-core.

It may even work.   I don’t know how long one must sleep in a hypoxic tent in order to show the distinctive physiological and structural adaptations we observe in natives of the high Andes, but all the tenters I know are pretty keen about it. Hell, I’d sleep in one myself just because it’s so cool, if the price tag weren’t a sweet $US 7,500. 

Me, I’ve always relied on my general sloth and distraction to provide me with the training benefits of a poor man’s hypoxic tent.  I forget to breathe, and my automatic breather thingy doesn’t work so well anymore. Frequent use of public toilet facilities ( a generous characterization ) in the Middle East induces adaptations, too: an habitual, deep-rooted disinclination to breathe at all.  Blue-Faced Apnea – the lesser of two evils.

Then there’s my old friend Zax – not his real name, for reasons which will become obvious anon. 

You want hard core ? Zax, a graying, somewhat decrepit Carribbean freediver with a truly horrifying aquatic resume, caught wind of the hypoxic tent thing and came up with a highly original, unique method of inducing hypoxic adaptation.

Instead of reducing the amount of oxygen available in the air he breathes, Zax decided to reduce the amount he delivered to his bloodstream. 

He came up with a drug that induces profound hemolytic anemia.

Zax let me in on his little experiment a few months ago, when he was a few months into it.  He told me he’d dropped his hemoglobin from 16.2 to 10.0, and his hematocrit from 46% to 31%.

“Meet me at the water, “ he growled. “Time to see what’s what.”

I wasn’t particularly concerned. This is actually not the craziest thing Zax has ever done, not by a long shot. I figure the guy’s made it this far, so he must have some idea what he’s doing. Still, I thought it wise to seek clarification.

“Zax, man, are you sure ?  I’m looking at WebMD right now and with numbers like those you’re lucky you don’t black out changing the TV channel”

Zax, on the other end of the line, gurgled, harrumphed and then went quiet. For what seemed like an awfully long time.

“Zax ?” I tested.

“Meet me at the water, “ he growled. “ Time to see what’s what.”

Uh –oh.  “You just said that !” I pointed out.

“Really ?” Zax asked, dully. “ I did ? I said it ? I know I thought it.  I –“

“Zax, let’s do this at the pool.”

Gentle readers, intrepid freedivers and philosophers all: do not try this at home. This is not good, clean fun. This is nuts. Zax has led a full and storied life, and nobody will miss him when he’s gone. You – your whole lives are ahead of you. Read, learn, but do not do.

The first symptom of profound anemia I noticed, then, was a slight brain fog. Old Zax,like a religious apostate, had many small lapses and seemed always to be on the brink of a major one. I was able to persuade him our field tests should be conducted in a nice, controlled indoor pool rather than miles offshore Florida in the Atlantic. He agreed, but then showed up 3 hours late at the pool. He’d gone and sat on the dock, waiting for me, even though we’d clearly agreed on the pool and not the boat.

No matter.

At the pool, I noticed that Zax looked mighty pale. He’s usually a pretty nut-brown, tropical-looking fellow, but now he looks like Stilton cheese. Transparent skin. I checked out the insides of his eyelids, usually an scarlet, iron-rich meat: pasty pale.  Palms, too.  The effort of changing out of his street clothes and into his wet suit had him breathing hard – and this is a guy who normally runs hills for light relaxation.

We decided to check him out with a series of dry statics, poolside. Now, Zax is not a competitor and never trains for freediving except by freediving – or didn’t, until he launched this bizarre anemia project. In any case, he assured me as he lay down on his back that he’d benchmarked himself before starting the drug regimen and had pulled a clean 6:20 after warm-ups of 3:30 and 4:30.

He did a 5-minute vent, then sucked and held.  He lasted a little over a minute.

“That’s not too encouraging,” I suggested. “ Maybe this isn’t such a great idea.”

“I forgot.” he insisted, “That’s all. I forgot what I was doing. Again.”

Another 5-minute vent, suck and hold. Better – he finished his 3:30 with no visible signs of distress, although I thought for a while during the hold that he’d somehow managed to doze off with his tongue magically locking his airway closed.  We exchanged a few words, then Zax said he wanted to rest up before doing his 4:30 and his go-for-it.  I got up and went for a squirt.

When I returned, Zax was snoring.

A few minutes later, one eye suddenly popped open.

"Get in the water," he ordered.

With considerable apprehension I joined Zax in the chest-deep water at the head of a 25-meter lap lane.

“Usually, I do a 100 –meter dynamic, no fins.” He mumbled. “ Given the statics I just did, I might be able to do that now.”

Uh-oh. Ahem…..

“Zax, you did a minute, a 3:30 and then you fell asleep.” I asserted.

He paused, figuring, puzzling, then shrugged it off.

"Spot me !” he said, and started his breathe-up.

Me, I clutched the kickboard and bet myself Zax wouldn’t even reach the end of the lane, 25 meters away.  In the locker room he looked worse off than the octogenarians who hung out there forgetting to go home. He shuffled rather than walked, and his normally heroic posture was now all hunched over and saggy. If I didn’t know this was all the temporary effect of his zany drug experiment, I’d have pegged him as a goner.


Zax stood in the warm water, eyes closed, belly swelling to suck in the air he then slowly pushed out over pursed lips. As I watched, a transformation came over him. He slowly became himself again. Of course. Zax is a waterman, an aquatic creature.

He was home.

Decades of habit kicked in. His breathe-up was practiced, efficient and serene. He drew in his last breath  – belly, sides, chest, shoulders, throat, mouth. Zax didn’t pack, he never liked packing, but it seemed to me that he got those liters in there as he always had. He slipped into the water and began his relaxed, slightly comical and highly personalized frog-kick. I churned along above him with the kickboard.

He made it across the pool in 4 strokes, and turned as he always had. The trip back was about the same – a lifetime of  apnea swimming yields habits of a lifetime. He didn’t speed up, didn’t slow down. Twenty-five seconds each way.

As he glided toward the 50-meter mark, he looked . .  normal. It seemed as though the water had restored him, as if his parched tissues were soaked and vital again. I thought of beached dolphins, put back in the sea, revived. He turned, and headed down the third length.

Zax completed a 75 – meter dynamic apnea swim, with no fins. His finish was certainly clean by AIDA competition standards, although he admitted it was his definite and absolute limit. After resting up for a few, he wanted to keep doing apnea laps, but I had to move on to my next engagement and so, thankfully, he agreed to go home.

Back up on the floor, he was sick old Zax again. He shuffled along slowly, except when he stumbled. He couldn’t find his locker, and then couldn’t figure out how to open the lock. He was sitting on a bench when I went to the shower, and was still sitting there when I returned. A substantial puddle had formed under him.

He looked up at me. “ It’s amazing,” he said. “ In the water, everything is different. I’m weaker, sure, but not like on dry land. I felt fine at 75 meters, no pain, no stress, just total hypoxia and knowing that that was the limit.” 

On the drive home, I reflected on what I’d seen.  Look, we both know Zax isn’t taking a drug just to do a freediving experiment. He’s sick, very sick, and these drugs are part of a brutal but effective treatment that’s going to save his peculiar and arguably worthless life. There was no need for he and I to talk about this, not once he’d got in the water. Once he’d got back home, where he belongs. The waters are our home, we freedivers. There was a time when the waters gave us all we needed, and what we now learn from Zax is that for each of us, that time may well come again.

Paul Kotik
Paul Kotik
Paul Kotik has been a Staff Writer and Freediving Editor for He lives in Florida, USA with his family.