鈥淚t鈥檚 Like They Have a Superpower鈥: Genetic Analysis of All-Women Extreme Divers Finds Changes Linked to Blood Pressure, Cold Tolerance
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A new analysis of a group of all-women extreme divers off the coast of Korea has uncovered genetic differences that could help them survive the intense physiological stresses of free-diving鈥攁nd could ultimately lead to better treatments for blood pressure disorders.
The researchers worked with the Haenyeo: women who have spent their whole lives diving in the waters off Jeju Island, 50 miles south of mainland South Korea. They free-dive up to 60 feet below the surface to harvest seaweed, abalone, and other food items from the seafloor, spending hours a day in the water all year round.
For hundreds of years, Haenyeo diving was a staple of Jeju鈥檚 economy and culture, although the practice is now waning. Today, most divers are in their 60s and 70s.
鈥淭hey鈥檙e absolutely extraordinary women,鈥 says assistant professor of biomedical informatics at 人妻中出视频 of Utah 人妻中出视频 and the senior author on the study. 鈥淓very day, they head out and get in the water, and that鈥檚 where they work all day. I saw women over 80 diving off a boat before it even stopped moving.鈥
Key points:
- A group of all-female subsistence free-divers in South Korea spends hours a day in the ocean, all year round.
- They dive throughout pregnancy and into their 70s and 80s.
- Researchers found that this population has genetic differences that may lower blood pressure and improve cold tolerance while diving.
IMPACT: Results could advance care for stroke and other conditions related to high blood pressure.
To figure out if the Haenyeo鈥檚 diving abilities are aided by differences in genetics, the researchers measured physiological variables related to diving ability, such as blood pressure and heart rate. They then sequenced participants鈥 DNA鈥攁nd found two changes related to diving physiology that could give the Haenyeo advantages underwater.
Adapting to a high-pressure environment
Haenyeo divers are more than four times more likely than mainland Koreans to have a genetic change associated with lower blood pressure while diving. The researchers believe this difference could keep divers and their unborn 人妻中出视频ren safe when diving during pregnancy.
Breath-hold diving not only limits the body鈥檚 oxygen supply but also raises divers鈥 blood pressure during a dive, the researchers say. Holding one鈥檚 breath in other contexts, such as sleep apnea, is associated with pregnancy-related blood pressure disorders, although it鈥檚 unknown whether diving causes the same effect.
The researchers speculate that if the genetic change helps lower blood pressure, it could be especially vital for the Haenyeo. These women dive throughout pregnancy and must avoid blood pressure conditions such as preeclampsia, which can be fatal. 鈥淭his is not something that every human or every woman is able to do,鈥 says postdoctoral researcher in evolutionary biology at 人妻中出视频 of California, Los Angeles, and the first author on the study. 鈥淚t鈥檚 kind of like they have a superpower.鈥
Cold comfort
A second genetic difference is related to pain tolerance鈥攕pecifically, cold-based pain. Air temperatures off Jeju Island drop to around freezing in the winter, but the Haenyeo don鈥檛 stop diving. 鈥淚 asked them once if they would stop diving if it got cold enough,鈥 Ilardo says. 鈥淭hey said that as long as the wind alarm doesn鈥檛 go off, they鈥檒l still get in the water.鈥 She clarifies, 鈥淭he wind alarm is to keep them from blowing out to sea.鈥
The team didn鈥檛 measure individuals鈥 cold tolerance, so they can鈥檛 say whether the change they see may be important for the Haenyeo鈥檚 ability to dive year-round. But they plan to investigate the difference further in future work.
The genetic differences that could boost diving ability are found throughout the population of Jeju Island. But much of what makes the Haenyeo women special comes from a lifetime of practice. Researchers have long known that when anyone dives鈥攖rained or untrained, Haenyeo or not鈥攖heir heart rate reflexively drops to conserve oxygen for longer. For an average untrained person from Jeju Island, heartbeat slows down by about 20 beats per minute over the course of a simulated dive. For Haenyeo with a lifetime of diving experience, heart rate drops by up to twice that.
Advancing health for all
The researchers hope that their discovery of a genetic difference linked to blood pressure will ultimately advance care for health conditions, like stroke, that are related to high blood pressure.
Intriguingly, Jeju Island has one of the lowest rates of stroke mortality in Korea, raising the possibility that the genetic change could help protect against stroke, Ilardo says.
鈥淚f there鈥檚 something about it that actually reduces the risk of stroke mortality, then we could help people everywhere by understanding what鈥檚 special about these women.鈥
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This research is published in Cell Reports as 鈥溾
This research was supported by the Office of Naval Research (N00014-20-1-2556), the National Institute of 人妻中出视频 (NIGMS R35GM153400, NHGRI R00HG011658), the National Science Foundation (Graduate Research Fellowship 2146752), the UC MEXUS-CONACYT Doctoral Fellowship, and the Fulbright-Garc铆a Robles.鈥
Content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of 人妻中出视频.