For hundreds of years, a group of remarkable women has lived and worked along the rocky coast of Jeju Island in South Korea. These women are known as the Haenyeo, which means “sea women.”
They are famous for diving deep into the ocean without any breathing equipment to collect seafood such as abalone, sea cucumbers, and seaweed. What makes them even more extraordinary is that many of them continue diving well into their 60s, 70s, and even 80s. Their strength, endurance, and ability to handle the cold sea have amazed visitors and scientists for many years.
Now, new research suggests that the Haenyeo may have special genetic traits that help them survive the extreme conditions of their work. Scientists believe these traits may not only explain how the divers manage such demanding lives but could also provide clues for treating serious health problems, including high blood pressure.
The study was carried out by a team of researchers led by Melissa Ilardo from the University of Utah. The results were published in the scientific journal Cell Reports. The researchers wanted to understand how the Haenyeo are able to dive repeatedly into cold water while holding their breath for long periods. To find answers, they studied the divers’ heart rate, blood pressure, and DNA.
Jeju Island lies about 80 kilometers south of the Korean mainland. For centuries, fishing and sea harvesting have been a key part of life there. In the past, men often worked in agriculture or traveled for trade, while women took on the difficult task of diving in the ocean to gather food.
Over time, this tradition became a strong cultural symbol of the island. Today, the Haenyeo are considered a national treasure in South Korea, and their culture has been recognized by UNESCO as an important cultural heritage.
During their work, Haenyeo divers can reach depths of around 20 meters while holding their breath for more than a minute. They dive again and again for several hours each day. In winter, the sea around Jeju Island becomes very cold, yet the divers still continue their work. This harsh lifestyle has led scientists to wonder whether their bodies have changed over generations to help them survive.
When people dive underwater and hold their breath, the body activates something called the diving reflex. This natural response helps save oxygen. The heart slows down, blood moves away from the arms and legs, and more oxygen is directed to vital organs such as the brain. For most people, the heart rate slows by about 20 beats per minute.
However, the researchers found that the Haenyeo divers showed a much stronger response. Their heart rates could slow down almost twice as much during dives. This helps them conserve oxygen and stay underwater longer.
But training alone does not explain everything. When the scientists examined the DNA of the Haenyeo, they discovered two genetic differences that may give them additional advantages.
The first genetic change is related to blood pressure. Normally, when a person dives and holds their breath, their blood pressure rises. This increase can sometimes be dangerous, especially during pregnancy, because high blood pressure is linked to a serious condition called preeclampsia. Preeclampsia can harm both the mother and the baby.
The researchers found that many Haenyeo carry a gene variation that may help prevent blood pressure from rising too much during diving. In fact, this gene variation was more than four times more common among people from Jeju Island than among people living on the Korean mainland.
This may explain why Haenyeo women have historically been able to continue diving safely even while pregnant, something that would be very risky for most people.
The second genetic difference appears to affect how the body senses cold. The ocean around Jeju can become extremely cold during winter months, yet the Haenyeo continue to dive throughout the year.
Although the researchers did not directly test cold tolerance in the divers, they found a gene connected to how people experience cold pain. This genetic change may make the Haenyeo less sensitive to cold temperatures, helping them stay in freezing water for long periods.
Interestingly, these genetic traits are not found only in the divers themselves. Many other people living on Jeju Island also carry them. This suggests that the genes may have developed in the population over many generations.
However, the scientists believe that the Haenyeo’s lifelong training and experience play an equally important role. Years of repeated diving strengthen the body’s natural responses and improve the divers’ ability to manage oxygen and stress underwater.
The discovery has attracted attention because of its possible medical benefits. High blood pressure is one of the leading causes of heart disease and stroke worldwide. If the gene variation found among the Haenyeo helps regulate blood pressure, researchers may one day use this knowledge to develop new treatments or medicines.
There is another interesting clue supporting this idea. Jeju Island has one of the lowest death rates from stroke in South Korea. Scientists are now exploring whether the same genetic factors discovered in this study may partly explain this pattern.
The story of the Haenyeo shows how human bodies can adapt to challenging environments over time. Their lives combine culture, tradition, hard work, and possible biological change. While more research is needed to fully understand these genetic traits, the findings open new doors for studying how the human body deals with stress, cold, and lack of oxygen.
What began as an investigation into a traditional diving culture may eventually help scientists learn more about heart health and blood pressure. The incredible sea women of Jeju Island are not only guardians of an ancient way of life but may also hold valuable clues that could improve health for people around the world.
If you care about high blood pressure, please read studies about unhealthy habits that may increase high blood pressure risk, and drinking green tea could help lower blood pressure.
For more information about high blood pressure, please see recent studies about what to eat or to avoid for high blood pressure, and 12 foods that lower blood pressure.
If you care about high blood pressure, please read studies that early time-restricted eating could help improve blood pressure, and natural coconut sugar could help reduce blood pressure and artery stiffness.
For more information about blood pressure, please see recent studies about How to eat your way to healthy blood pressure and results showing that Modified traditional Chinese cuisine can lower blood pressure.
The research findings can be found in Cell Reports.
Copyright © 2026 Knowridge Science Report. All rights reserved.
