• Research identifies genetic variations in Jeju Island's Haenyeo divers linked to lower blood pressure and cold tolerance.
• These adaptations may have evolved to protect pregnant divers and their unborn children from hypertension-related complications.
• The findings offer potential for developing new treatments for blood pressure disorders and understanding human adaptation to extreme environments.

A recent study published in Cell Reports has revealed that the Haenyeo, female free divers of Jeju Island, South Korea, possess unique genetic adaptations related to lower blood pressure and cold tolerance. These 'sea women' have practiced free diving for generations, harvesting seafood from depths of up to 60 feet without breathing apparatus. The research suggests that natural selection has favored these genetic traits, potentially protecting pregnant divers from hypertension. The study involved genomic analysis and physiological measurements of Haenyeo divers, non-diving Jeju residents, and mainland Koreans.

• What: Genetic adaptations in Jeju Island's Haenyeo divers, including lower blood pressure and cold tolerance, discovered through genomic analysis and physiological measurements.
• Who: Key individuals include Melissa Ilardo (University of Utah), Diana Aguilar-Gómez (UCLA), Joo-Young Lee (Seoul National University), and Nikolai Nordsborg (University of Copenhagen). The primary subjects are the Haenyeo divers of Jeju Island, along with control groups from Jeju and mainland Korea.
• When: The study was published in Cell Reports on May 2, 2025. The Haenyeo tradition spans generations, with evidence suggesting adaptations evolved over centuries.
• Where: The research focuses on Jeju Island, South Korea, with comparisons to mainland Korean populations. The Haenyeo divers operate in the waters surrounding Jeju Island.

The study provides compelling evidence for genetic adaptations in the Haenyeo population, driven by their unique diving lifestyle. The lower blood pressure adaptation is particularly significant, potentially protecting pregnant divers from complications. While the sample size was relatively small, the findings are supported by comparisons with other populations and physiological data. The research highlights the importance of studying diverse populations to uncover novel insights into human adaptation and disease. Further research is needed to fully understand the mechanisms underlying these adaptations and their potential medical applications. The Haenyeo culture is dying out which makes studying them even more important.

When you’re diving, your blood vessels are responding in complicated ways to try to keep your vital organs safe as your oxygen is running low. It becomes a trade-off between short term and long term benefits — what keeps you safe while you’re diving might lead to complications further down the line. Evolution seems to have found a way to balance this out — a genetic variant that may protect divers while they’re holding their breath and beyond.

This study raises more questions than it answers, but first and foremost, it shows these women are extraordinary. There’s something biologically different about them that makes them extremely special, no matter how you characterize it, and what they do is unique and worth celebrating.

The study of Jeju Island's Haenyeo divers has revealed unique genetic adaptations that offer valuable insights into human physiology and adaptation to extreme environments. The findings suggest that generations of diving have led to the evolution of traits such as lower blood pressure and cold tolerance, with potential implications for treating related medical conditions. As this unique cultural tradition faces decline, continued research is crucial to fully understand and leverage these adaptations for the benefit of global health.