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Haenyeo women, aged between 60-80 years of age, dive in freezing waters.
Far from the glittering capitals of modernity, on a windswept volcanic island off the southern coast of South Korea, live some of the world’s most remarkable women. Known as Haeneoor “sea women”, these female free divers of Jeju Island have, for centuries, braved the bitterly cold waters of the Korea Strait without the aid of oxygen tanks, plunging into the deep to harvest seaweed, shellfish, and abalone.
What makes their feats even more astonishing is their age. Many Haeneo are between 60 and 80 years old. They continue to dive, sometimes for hours each day, even in near-freezing temperatures, their resilience defying both physical expectation and scientific logic. Until now.
A groundbreaking study published in the journal Cell Reports uncovered the genetic code behind their superhuman endurance. Researchers identified two key adaptations in the DNA of Haeneo women – mutations so rare and advantageous that they might redefine our understanding of human limits.
The first genetic trait discovered involves a gene variant that stabilises blood pressure during deep dives. This not only protects the divers themselves but also offers a remarkable safeguard during pregnancy – a period especially sensitive to cardiovascular fluctuations. Indeed, it’s not uncommon for some Haeneo to continue diving while pregnant, despite the potential for complications such as preeclampsia.
The second adaptation may be even more astonishing. It provides an increased tolerance for cold – a trait that allows these women to endure wind-chilled waters hovering near zero degrees Celsius. Their response to winter diving is characteristically stoic: “Until the wind alarm rings,” they say, “we will keep diving into the sea.”
Jeju Island, located approximately 80 kilometres south of mainland Korea, is more than just the home of the Haeneo – it’s a cradle of a cultural lineage shaped by the sea. The island’s unique dialect, peppered with short, clipped sentences, is believed by linguists to have evolved in part to accommodate the rapid communication needed between divers who surface only briefly to exchange information.
While genetics plays a critical role, scientists emphasise that the prowess of the Haeneo is not solely encoded in their DNA. It is also a product of relentless training and years of lived experience. The human diving reflex – a physiological response that slows the heart rate to conserve oxygen – is notably more pronounced in these women. A typical diver’s heartbeat might slow by 20 beats per minute. In a seasoned Haeneoit slows by nearly twice that, dramatically increasing oxygen efficiency.
This genetic resilience may offer hope far beyond Jeju. According to Dr Melissa Ilardo, a genetics researcher at the University of Utah and one of the authors of the study, understanding the physiological mechanisms behind the abilities of a Haeneo woman could inform treatments for high blood pressure and stroke – conditions that afflict millions worldwide.
“If we can understand how their bodies manage oxygen and regulate blood pressure so effectively, we may be able to translate these insights into therapies for cardiovascular diseases.” Ilardo said.
