In Jeju, the largest south Korea island, a group of underwater fishing called Haenyeo lives, which in Korean means “women of the sea”: These sirensoften no longer very young and some ultraottanententenimmerse themselves Up to ten meters underwater without oxygen cylinders to fish a little bit of everything – From sea urchins, algae, octopus. Each immersion lasts about 30 seconds, but to fish enough food Korean sirens They remain in the water even for four or five hours.
A study published on Cell reports has analyzed the genomes of these women by discovering that, over the years, they have developed several genetic adaptations that allow them to swimming for a long time in icy waters without going into hypothermia.
Resistant to the cold. To understand more, the researchers analyzed the genomes of 30 women Haenyeo, 30 non -Haenyeo island, and 31 non -island Koreans. All participants were on average 65 years old.
In addition to genetics, scholars also monitored the heartbeat and blood pressure during “simulated diving”: two main genetic adaptations in the Haenyeo – one, associated with tolerance to the cold, have emerged, which would protect them from hypothermia; Another associated with a decrease in diastolic pressure.
Slowed beat. During the simulations, the cardiac rhythm of the Korean sirens fell on average of 18.8 beats per minute, while that of the women of Jeju non -fishing of only 12.6 beats per minute. A slower heart rate helps the body save energy and preserve oxygen reserves, a remarkable advantage when you immerse yourself several times taking breath only once.
Genetic training. The interesting aspect is that all the inhabitants of the island involved in research share the same origins, which means that Genetic changes are not inheritedbut fburning of a habit Repeated in the time that contributed to an evolution: after generations of diving, the heart of the Haenyeo trained to slow down – in one of the cases analyzed the rhythm has even decreased by 40 beats in less than 15 seconds.
Unfortunately, the tradition of the Haenyeo is being lost, and many believe that the current generation will be the last: the genetic and physiological traits could however remain long, and studying them deeply could help us develop therapies in the future to treat different pathologies, such as hypertensive disorders typical of pregnancy and stroke.
