How Korea's Haenyeo developed extraordinary cold resistance that lets them dive into near-freezing seas without oxygen tanks, even in their 70s

For centuries, the Haenyeo, South Korea's legendary "sea women", have ventured into the cold waters surrounding Jeju Island armed with nothing more than a knife, a floating buoy and their ability to hold their breath.

Many continue diving well into their 60s, 70s and even 80s, harvesting abalone, sea urchins, octopus and shellfish without scuba gear or compressed oxygen.Their endurance has long fascinated scientists.

How can elderly women repeatedly enter near-freezing seawater, remain underwater for minutes at a time and emerge seemingly unaffected?

A scientific study titled ‘The acclimatization of Haenyeo to a cold environment and occupational characteristics evaluated by orexin and irisin levels’ by Inho Lee, Yong-Jin Lee, Eun-Chul Jang, Soon-Chan Kwon, Young-Sun Min, Jisuk Yun, Taehwan Park, Hye-Jin Lee, Eonah Choo and Jeong-Beom Lee has now revealed that the answer lies deep within their physiology.

The research shows that decades of cold-water diving have altered the way their bodies generate and conserve heat, giving them a remarkable tolerance to icy environments.