These Remarkable Sea Divers May Hold Clues to Better Blood Pressure Control

For generations, women known as Haenyeo have been diving into the cold waters around South Korea’s Jeju Island to collect seafood without breathing equipment. Now, scientists are studying their extraordinary physiology for clues that could eventually improve our understanding of blood pressure and cardiovascular health.

Research into these traditional sea divers suggests that both genetic adaptation and lifelong diving training may influence how the human body responds to the intense physiological demands of breath-hold diving.

A remarkable response to diving

When a person holds their breath and submerges their face in cold water, the body activates what is known as the diving response.

Heart rate slows, blood vessels in parts of the body constrict and blood flow is redirected towards vital organs such as the brain and heart.

This response helps conserve oxygen, but it can also cause blood pressure to rise significantly during a dive. Scientists are interested in understanding how experienced divers cope with these changes.

What makes the Haenyeo different?

The Haenyeo have developed remarkable abilities through generations of diving and years of personal experience.

Research has found evidence that a genetic variant common among people from Jeju Island may help moderate the blood-pressure response associated with immersion. A separate adaptation found among Haenyeo appears to be linked to their lifelong diving training and allows their heart rates to slow substantially during simulated dives.

Scientists believe these adaptations may provide valuable insight into how the human cardiovascular system responds to low-oxygen environments.

Could their biology help medicine?

The findings do not mean that diving is a treatment for high blood pressure. Instead, researchers are interested in the biological mechanisms that allow these divers to cope with extreme changes in oxygen availability and cardiovascular pressure.

Understanding these mechanisms could eventually help scientists investigate new approaches to conditions involving blood pressure, stroke and other cardiovascular problems.

The research is particularly interesting because the adaptations appear to involve both genetics and training, offering clues about how the human body can adjust to demanding environments.

The wider story of human diving adaptations

The Haenyeo are not the only population attracting scientific attention.

Researchers have also studied the Bajau, an Indigenous sea-faring population in Southeast Asia known for extraordinary breath-hold diving abilities. A 2018 study found evidence that natural selection had contributed to larger spleens among the Bajau, potentially providing a greater reservoir of oxygenated red blood cells during dives.

Together, research into these populations is helping scientists understand how humans can adapt to environments where oxygen availability is severely restricted.

A window into future medical research

The biology of traditional sea divers offers scientists an unusual window into the body’s ability to cope with stress.

While more research is needed before these discoveries can translate into medical treatments, the findings demonstrate how studying populations with extraordinary physiological abilities can reveal mechanisms that may eventually benefit wider healthcare.

For the Haenyeo, diving is a centuries-old way of life. For researchers, their remarkable physiology could provide new clues about how the human body regulates blood pressure, conserves oxygen and protects vital organs under extreme conditions.