Are Some People Born To Freedive

24/02/2025

The first time I held my breath for over two minutes, I thought I had unlocked a secret superpower. My body tingled, my heart slowed, and for a brief moment, I felt like I could stay underwater forever. But then my lungs spasmed, my brain went into survival mode, and I shot to the surface, gasping like a beached fish.

Some people, though, seem to be built differently. They glide through the depths with effortless grace, pushing past the limits of human endurance like it’s nothing. Their heart rate plummets, their bodies resist the crushing pressure, and their minds stay eerily calm. We call them elite freedivers. But the real question is—are they made, or were they born this way?

Turns out, freediving genetics might have a lot more to do with it than we think.

The Ocean in Our Blood

There’s a theory that all humans are, in some way, descendants of ocean dwellers. It’s the kind of thing that makes sense when you’re floating weightlessly in the sea, watching your own shadow ripple across the sand below.

While that might be more poetic than scientific, what is backed by research is that some populations have evolved in ways that make them better at breath-hold diving. The Bajau sea nomads, often called the “Sea Nomads,” are the best-known example.

These Indonesian and Filipino divers have been living and hunting in the ocean for thousands of years. They spend so much time underwater that their spleens—organs you probably don’t think about much—have actually become bigger. That’s important because the spleen acts like a natural oxygen efficiency reservoir. It contracts during breath-holding, pushing more oxygen-rich red blood cells into circulation, delaying the need to breathe.

In 2018, a study published in Cell confirmed that the Bajau have a genetic adaptation in the PDE10A gene, which is linked to this spleen adaptation. Their spleens are 50 percent larger than those of their land-dwelling neighbors. That’s not just training or diet—that’s evolution in action.

Which begs the question: Do elite freedivers have similar genetic advantages in freediving?

The Science of Holding Your Breath

The ability to dive deep isn’t just about lung capacity. In fact, lung size has surprisingly little to do with it. Freediving physiology relies on a combination of factors—some trainable, some potentially hardwired in DNA.

First, there’s the mammalian dive reflex. It’s an ancient response triggered when the face hits cold water. Your heart rate slows, blood vessels in your limbs constrict to preserve oxygen efficiency for your core, and the spleen adaptation we talked about earlier kicks in to boost circulation. Everyone has this reflex, but some have it much stronger than others. Scientists suspect freediving genetics play a role in how dramatically a person’s body responds.

A 2019 study in Frontiers in Physiology looked at trained freedivers versus non-divers and found that elite freedivers had significantly stronger mammalian dive reflex responses. Some of this is training, but researchers suggested that genetic predisposition might determine just how good someone can become.

And then there’s hypoxia tolerance—how well a person’s brain and body function with low oxygen. Some freedivers can hold their breath for over eight minutes, descending past 100 meters without blacking out. Studies suggest that freediving adaptation linked to hemoglobin levels, oxygen saturation, and even the way the brain processes CO2 might give certain individuals an edge.

One study on Sherpas, who are genetically adapted to low-oxygen environments in the Himalayas, found that they have unique variants in the EPAS1 gene, which helps them use oxygen more efficiently. While no direct studies have linked this gene to freediving performance, it raises an interesting possibility—some people might naturally be better at surviving with less air. 

Nature vs. Training: Can You Hack Your DNA?

So what does all this mean for the average freediving training enthusiast? If you weren’t born with Bajau sea nomads-level spleens or Sherpa-like hypoxia tolerance, are you doomed to be mediocre in the water?

Not necessarily. Genetic advantages in freediving may provide an edge, but freediving training is still largely a sport of adaptation. The human body is ridiculously good at changing itself to meet demands. Training, diet, mental conditioning, and exposure to hypoxia tolerance all push the body toward improvement. Even the spleen can adapt over time, though not to the same extent as the Bajau sea nomads.

So, Are Freedivers Born or Made?

The real answer, like most things in science, is: It’s complicated. Some elite freedivers probably do have genetic advantages in freediving. Maybe they have stronger mammalian dive reflex responses, higher hemoglobin levels, or spleens that contract like a power booster when they hit the water. The Bajau sea nomads exist as living proof that evolution can shape human breath-hold diving ability.

But freediving adaptation is also about pushing limits, training the body and mind, and learning to be comfortable in discomfort. Genes might get someone to a certain level faster, but dedication, freediving training, and mental control are what separate the great from the legendary.

So if you weren’t born with deep diving genetics, don’t worry. Your body is still capable of incredible things. And at the end of the day, freediving performance is about more than just numbers—it’s about the feeling of weightlessness, the silence of the deep, and the sheer joy of being one with the ocean. Even if your spleen adaptation is disappointingly normal.