How Do Humans Hold Their Breath for Minutes — or Even Hours — Without Gear?
Meet the Bajau, the Sea Nomads Whose Biology Defies Expectations
In a remote part of Southeast Asia, a seafaring people known as the Bajau have mystified scientists and explorers alike. For generations, they have lived intertwined with the ocean, diving to astounding depths and spending hours beneath the waves — all without the aid of modern breathing apparatus.
What powers these extraordinary feats? Recent research has unveiled a surprising answer: a genetic mutation linked to enhanced physiological traits, hinting at an evolutionary marvel hidden beneath the surface of human biology.
Life on the Water’s Edge
The Bajau, often called the “Sea Nomads,” have called the waters around Indonesia, Malaysia, and the Philippines home for nearly a millennium. Living in stilt houses that rise above coral reefs and open seas, their culture is deeply rooted in the rhythms of the ocean.
From childhood, Bajau learn the art of freediving. Equipped with little more than handmade wooden goggles and weights to help them descend, they dive to hunt fish and gather seafood with breathtaking skill. It’s not uncommon for them to remain underwater for several minutes at a time, sometimes diving to depths exceeding 70 meters (over 230 feet). Some spend as much as 60% of their waking hours submerged, a lifestyle utterly alien to most of us.
But skill alone doesn’t explain their unmatched endurance.
Biology Meets Bravery
A groundbreaking study led by University of Copenhagen researcher Melissa Ilardo revealed a striking physical difference: Bajau divers possess significantly larger spleens than their non-diving neighbors. While this organ may seem unremarkable, it plays a vital role in oxygen management. During prolonged breath-holding, the spleen contracts, releasing a reservoir of oxygen-rich red blood cells to keep the body fueled underwater.
Ilardo describes this as a kind of “natural scuba tank,” a biological adaptation allowing the Bajau to hold their breath far longer than average humans. The study found Bajau spleens to be about 50% larger on average, a remarkable physiological advantage that translates directly into longer, deeper dives.
The Genetic Puzzle
Delving into genetics, the researchers identified a gene called PDE10A as a key player. Known in animal studies to influence thyroid hormone levels, PDE10A appears to regulate spleen size in the Bajau, providing a genetic basis for their extraordinary diving ability.
“This gene stood out when we compared Bajau DNA with that of neighboring populations,” explained Professor Rasmus Nielsen of UC Berkeley, a co-author of the study. The finding adds to a growing body of evidence showing how humans adapt biologically to extreme environments — similar to Tibetan highlanders who thrive on thin mountain air.
Some scientists speculate that these adaptations may even trace back to ancient human species like Denisovans or Neanderthals, whose interbreeding with modern humans may have left behind hidden genetic legacies.
Facing New Threats
Despite their awe-inspiring abilities and centuries-old traditions, the Bajau way of life is increasingly at risk. Community elder Santarawi Lalisan has spoken out about the rising tide of pollution and plastic waste invading their ocean home, threatening the ecosystems they rely on.
Coupled with climate change and encroaching modernization, these pressures cast uncertainty over the future of the Sea Nomads’ ocean-centered existence.
A Testament to Human Evolution and Resilience
The Bajau’s story is not just about remarkable diving skills—it’s a powerful example of human adaptability in the face of extreme environmental challenges. Their genetically enhanced spleens and time-honored diving culture offer living proof that our species can evolve physical traits to meet demanding conditions in real time.
Yet, as science peels back the layers of their biology, it also shines a light on the fragility of their traditions. Protecting the Bajau means safeguarding a unique chapter of human history—one that reveals the profound bond between people and the natural world.
Their legacy is a call to respect and preserve the delicate balance that allows extraordinary human potential to flourish.