Legendary divers in Korea have inherited 'superhuman' genes

The Haenyeo of South Korea’s southern coast continue a centuries-old tradition that sets them apart. These remarkable women – free divers of Jeju Island – plunge into the sea without oxygen tanks to collect abalone, seaweed, and other marine life.

Often in their 60s or 70s, they dive year-round, even in winter, sometimes to depths of 60 feet. Their way of life is disappearing, but new research suggests their legacy may stretch far beyond tradition – it might help unlock new insights into human health.

Unique genes in extreme divers

Scientists from the University of Utah Health and UCLA have studied the Haenyeo to understand how they handle the extreme physical stress of deep diving.

The findings reveal unique genetic features that could help regulate blood pressure and improve pain tolerance.

These traits may not only explain how the Haenyeo endure their harsh environment but also offer promising leads for treating blood pressure-related disorders.

The Haenyeo advantage

The study began with a simple question: Do the Haenyeo have a biological edge that helps them survive repeated dives into cold, deep waters?

Researchers looked at their heart rate and blood pressure during simulated dives, then sequenced their DNA. What they found were two genetic variants potentially tied to diving-related stress.

“They’re absolutely extraordinary women,” said Melissa Ilardo, an assistant professor of biomedical informatics at the University of Utah Health.

“Every day, they head out and get in the water, and that’s where they work all day. I saw women over 80 diving off a boat before it even stopped moving.”

Divers with protective genes

One of the most significant findings was a genetic change linked to lower blood pressure during dives. This change was more than four times as common in the Haenyeo compared to mainland Koreans.

Lowering blood pressure while diving may help protect them – and their unborn children – during pregnancy. While the dangers of breath-holding are well-known in other situations, such as sleep apnea, the researchers believe diving poses a unique challenge.

“This is not something that every human or every woman is able to do,” said Diana Aguilar-Gómez, a postdoctoral researcher in evolutionary biology at UCLA. “It’s kind of like they have a superpower.”

Tolerance for the cold

The second genetic difference relates to pain sensitivity, particularly to cold. Jeju Island winters can bring air temperatures close to freezing, yet the Haenyeo dive regardless of the chill.

“I asked them once if they would stop diving if it got cold enough. They said that as long as the wind alarm doesn’t go off, they’ll still get in the water,” noted Ilardo. “The wind alarm is to keep them from blowing out to sea.”

Although the researchers didn’t measure the women’s cold tolerance directly, the team suspects this gene may play a role in how the Haenyeo manage to dive year-round.

Future studies will look deeper into this genetic marker and what it might mean for pain management in colder climates.

Experience still matters

Genes alone don’t tell the whole story. Diving changes the body over time, and the Haenyeo show this through their powerful reflexes.

When anyone submerges underwater, the body slows the heart to conserve oxygen. In untrained individuals, the heart rate drops by about 20 beats per minute during a simulated dive. For the Haenyeo, this drop is nearly double.

This physiological adaptation likely comes from decades of diving, a skill that’s as much about muscle memory and discipline as it is about biology.

The team found that even people from Jeju Island who weren’t Haenyeo had a weaker version of this reflex, suggesting the full benefit comes only with practice.

Looking beyond the island

One of the most exciting possibilities is that these findings might help others. The genetic trait linked to lower blood pressure could aid in managing conditions like hypertension and stroke.

Jeju Island already has one of the lowest stroke mortality rates in South Korea. The researchers wonder if the same genes found in the Haenyeo divers might be partly responsible.

“If there’s something about it that actually reduces the risk of stroke mortality, then we could help people everywhere by understanding what’s special about these women,” said Ilardo.

While the Haenyeo’s way of life may be fading, their legacy might shape how we think about heart health for generations to come.

The full study was published in the journal Cell Reports.

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