Генетические особенности дайверов с острова Чеджу помогают бороться с сердечно-сосудистыми заболеваниями

Location: For centuries, the coastlines of South Korea’s Jeju Island have been home to the 해녀 (Haenyeo), an extraordinary community of all-female free-divers who plunge into the ocean to harvest seafood. Known as "women of the sea," these divers descend up to 60 feet below the surface without any breathing equipment, often staying underwater for minutes at a time. Remarkably, many of these women continue this grueling labor well into their 70s and 80s. While their feats have traditionally been credited to lifetime training, recent genetic and physiological research reveals that the Haenyeo possess unique physical adaptations that allow them to thrive in extreme underwater environments. The Mammalian Dive Reflex and Bradycardia When any human submerges their face in cold water, it triggers an involuntary survival mechanism known as the mammalian dive reflex. This reflex slows the heart rate and constricts peripheral blood vessels, shifting oxygen-rich blood away from the limbs and prioritizing vital organs like the brain and heart. However, clinical studies comparing the Haenyeo to non-diving women show that the divers have an exceptionally heightened response. During simulated dives, the Haenyeo’s heart rates drop approximately 50% more than those of non-divers. In extreme cases, researchers recorded a diver's heart rate plunging by 40 beats per minute within a mere 15 seconds of water contact. This severe, controlled bradycardia dramatically lowers oxygen consumption, allowing them to extend their breath-hold times significantly while searching the rocky sea floor for abalone and sea urchins. Scientists categorize this particular cardiovascular efficiency as an acquired physiological adaptation resulting from starting their training as young girls. Genetic Resistance to Frigid Waters While the dramatic drop in heart rate is largely a product of rigorous conditioning, other physical advantages are hardwired into their DNA. The waters surrounding Jeju Island frequently drop to 50 degrees Fahrenheit (10°C) or colder during the winter months. For generations, the Haenyeo dove in thin cotton swimwear before modern wetsuits were introduced, frequently working in freezing and even snowy weather. Genetic mapping conducted by an international team of scientists discovered that native residents of Jeju Island carry specific genetic variants linked to enhanced hypothermia and pain resistance. These specific gene variants alter how the body perceives cold and manages metabolic heat production. This evolutionary trait allows the Haenyeo to suppress shivering and tolerate severe physical discomfort longer than the average population, providing a distinct survival advantage in hostile marine environments. Vascular Compliance and Diver Health Plunging deep underwater subjects the human body to immense hydrostatic pressure, which forces blood from the extremities into the chest cavity, naturally causing a sharp spike in systemic blood pressure. For most individuals, repeated exposure to these pressure shifts can cause chronic vascular damage. Surprisingly, genetic testing revealed that the Haenyeo carry specialized gene variants that actively protect against high blood pressure. This genetic buffer maintains elasticity in their blood vessels, allowing their circulatory systems to accommodate extreme pressure changes smoothly. Historically, this adaptation proved vital for community survival: the Haenyeo routinely dove throughout their entire pregnancies, sometimes returning to the ocean just days after giving birth. Because high blood pressure poses severe risks during pregnancy, this evolutionary vascular compliance protected both mother and child from potential complications brought on by diving. Today, medical researchers are studying these specific traits to develop new treatments for civilian cardiovascular diseases. A Fading Biological Legacy The unique physical profile of the Haenyeo presents a fascinating intersection of intense physical training and localized natural selection. Unfortunately, this specialized human legacy is rapidly disappearing. Due to the physical hardships of the profession and the rise of alternative economic opportunities in South Korea, very few young women are entering the trade, leaving the current average age of the divers at around 70 years old. As the remaining generation of elder divers gradually retires, the world is witnessing the final chapters of a distinct, living community of human aquatic adaptation. Links • Jeju Haenyeo Museum Official Site: • NPR Short Wave Podcast Interview • Koreana Magazine Journal Feature: • Korea Heritage Service ICH Profile • Jeju Haenyeo Museum Official Site: • Smithsonian Magazine Genetic Study Feature • New England Aquarium Cultural Archive