For centuries, humans have dived beneath the waves to gather food from the ocean floor — a tradition that continues today as elite freedivers descend to record-breaking depths. Some scientists now suggest that humans may be more adapted to the sea than previously thought
World-record free divers are redefining human potential and challenging scientists' understanding of the human body.
#1
Alessia Zechinni floats calmly on the ocean’s surface, her eyes fixed on the sky, her mind completely still.
“When thoughts appear,” she says, “I gently let them go. I focus on my breath—it grounds me. That final breath is the deepest one. I fill my lungs with as much air as possible, preparing to dive farther than before.”
With a powerful kick, Zechinni begins her descent into the deep blue, arms extended above her head in perfect form. “After around 25 meters (80 feet), I ease into gentler kicks,” she explains. “By 60 meters (200 feet), I stop kicking altogether—I begin to free-fall. That part is magical. It's like flying underwater.”
Zechinni is no ordinary athlete. As a world-renowned freediver and author, she has shattered 40 world records and claimed over 30 international freediving medals—including 17 World Championship golds. In 2023, she dove to an astonishing 123 meters (404 feet) unassisted—an achievement few in the world can match.
But her accomplishments go beyond medals. Zechinni belongs to a rare group of elite freedivers capable of reaching incredible depths on a single breath. Increasingly, scientists believe this ability may not be as unnatural as once thought. Emerging research suggests that humans are more biologically equipped for deep diving than we realized—and that freediving may have shaped our evolutionary path.
Some researchers even propose that humans could be “natural divers,” not unlike otters or sea lions. And for a gifted few like Zechinni, their physiology rivals that of diving mammals such as seals.
Into the Deep: A Mental and Physical Mastery
Alessia Zechinni floats calmly on the ocean’s surface, her eyes fixed on the sky, her mind completely still.“When thoughts appear,” she says, “I gently let them go. I focus on my breath—it grounds me. That final breath is the deepest one. I fill my lungs with as much air as possible, preparing to dive farther than before.”
With a powerful kick, Zechinni begins her descent into the deep blue, arms extended above her head in perfect form. “After around 25 meters (80 feet), I ease into gentler kicks,” she explains. “By 60 meters (200 feet), I stop kicking altogether—I begin to free-fall. That part is magical. It's like flying underwater.”
Zechinni is no ordinary athlete. As a world-renowned freediver and author, she has shattered 40 world records and claimed over 30 international freediving medals—including 17 World Championship golds. In 2023, she dove to an astonishing 123 meters (404 feet) unassisted—an achievement few in the world can match.
But her accomplishments go beyond medals. Zechinni belongs to a rare group of elite freedivers capable of reaching incredible depths on a single breath. Increasingly, scientists believe this ability may not be as unnatural as once thought. Emerging research suggests that humans are more biologically equipped for deep diving than we realized—and that freediving may have shaped our evolutionary path.
Some researchers even propose that humans could be “natural divers,” not unlike otters or sea lions. And for a gifted few like Zechinni, their physiology rivals that of diving mammals such as seals.
#2
“In the past, I used to carry a torch,” she says, “but now I enjoy the blue becoming darker and darker. I use the fading light to know how deep I am.”
But beauty below the surface comes with a price.
“The deeper you go, the stronger the narcosis gets,” she explains. “It’s like you’re drunk.”
This altered state, known as the rapture of the deep, or nitrogen narcosis, is typically a risk for scuba divers who inhale compressed air. Yet elite freedivers like Zechinni can also experience this disorienting condition. As pressure increases with depth, nitrogen stored in the lungs becomes compressed and enters the bloodstream—triggering narcotic effects.
Under high pressure, nitrogen acts like a sedative. It can cause anxiety, drowsiness, euphoria, poor judgment, and even vivid hallucinations.
“To be drunk at over 100 meters (328 feet) isn’t ideal,” Zechinni says with a wry smile. “The key is staying focused—don’t think, just feel. Stay in the moment
Into the Abyss: Darkness, Pressure, and the Rapture of the Deep
As Alessia Zechinni descends further into the ocean, sunlight begins to fade, and the cold closes in around her. She doesn’t glance at the descent line that guides her; instead, her eyes remain fixed on the deepening blue, watching it dissolve gradually into darkness.“In the past, I used to carry a torch,” she says, “but now I enjoy the blue becoming darker and darker. I use the fading light to know how deep I am.”
But beauty below the surface comes with a price.
“The deeper you go, the stronger the narcosis gets,” she explains. “It’s like you’re drunk.”
This altered state, known as the rapture of the deep, or nitrogen narcosis, is typically a risk for scuba divers who inhale compressed air. Yet elite freedivers like Zechinni can also experience this disorienting condition. As pressure increases with depth, nitrogen stored in the lungs becomes compressed and enters the bloodstream—triggering narcotic effects.
Under high pressure, nitrogen acts like a sedative. It can cause anxiety, drowsiness, euphoria, poor judgment, and even vivid hallucinations.
“To be drunk at over 100 meters (328 feet) isn’t ideal,” Zechinni says with a wry smile. “The key is staying focused—don’t think, just feel. Stay in the moment
#3
At the bottom of the line, Alessia Zechinni pivots “super gently,” mindful of conserving every ounce of energy for what lies ahead.
“You’re less than halfway,” she says, “because the ascent is much harder than the descent.”
For the first 60 meters (200 feet), she powers upward with strong, deliberate kicks. By the time she reaches 35 meters (115 feet), a wave of relief hits—she spots the safety divers waiting for her. From here, she can ease up, knowing she’s no longer alone. Her movements slow as the surface draws near.
“It’s beautiful,” she reflects. “As you rise, the blue becomes lighter, brighter.”
And when she finally breaks through the surface, drawing in her first breaths of air, she feels the oxygen rushing back into her body—"filling every single cell," as she describes it.
By 2024, 7,269 people have stood atop Mount Everest, and over 700 have looked down on Earth from space.
But Zechinni belongs to an elite few who’ve looked up from the silent depths of over 100 meters (328 feet), with nothing but a single breath in their lungs and an iron will to survive.
The Ascent: Light, Struggle, and the Surge of Life
At the bottom of the line, Alessia Zechinni pivots “super gently,” mindful of conserving every ounce of energy for what lies ahead.“You’re less than halfway,” she says, “because the ascent is much harder than the descent.”
For the first 60 meters (200 feet), she powers upward with strong, deliberate kicks. By the time she reaches 35 meters (115 feet), a wave of relief hits—she spots the safety divers waiting for her. From here, she can ease up, knowing she’s no longer alone. Her movements slow as the surface draws near.
“It’s beautiful,” she reflects. “As you rise, the blue becomes lighter, brighter.”
And when she finally breaks through the surface, drawing in her first breaths of air, she feels the oxygen rushing back into her body—"filling every single cell," as she describes it.
By 2024, 7,269 people have stood atop Mount Everest, and over 700 have looked down on Earth from space.
But Zechinni belongs to an elite few who’ve looked up from the silent depths of over 100 meters (328 feet), with nothing but a single breath in their lungs and an iron will to survive.
#4
These extraordinary feats might sound superhuman—especially when compared to the average breath-hold of 30 to 90 seconds, or the Olympic swimming pool’s depth of just 2.5–3 meters (8–10 feet). But freediving isn’t just a modern marvel; it’s a deeply rooted part of human history.
Roughly 90,000 years ago, Neanderthals were diving to collect clam shells, so frequently that they developed signs of swimmer’s ear, a condition linked to constant exposure to cold water. By 350 BC, Aristotle wrote about sponge divers using lead weights to descend to the seabed. Meanwhile, Japan’s Ama fisherwomen have been freediving for over 2,000 years, harvesting seaweed and shellfish with nothing but lung power.
Perhaps most fascinating of all are the Bajau people of Southeast Asia—a nomadic, sea-dwelling tribe who have spent so many generations underwater, they’ve developed an evolutionary advantage. Bajau divers can spend up to five hours a day underwater, using wooden goggles, body weights, and—remarkably—an enlarged spleen that functions as a natural oxygen reservoir. It’s biology catching up with necessity: a real-life version of evolution crafting a “biological scuba tank.”
Extreme Breath: From Ancient Divers to Modern-Day Record Breakers
Pushing the boundaries of human physiology, freediving legends continue to redefine what the human body can endure. In 2014, Branko Petrovic held his breath for a staggering 11 minutes and 54 seconds. Nearly a decade later, in 2023, Alexey Molchanov descended to an unassisted depth of 133 meters (435 feet)—without weights or fins. Even more astonishing, in 2021, Budimir Šobat shattered the world record for static apnea underwater by holding his breath for 24 minutes and 37 seconds after inhaling pure oxygen.These extraordinary feats might sound superhuman—especially when compared to the average breath-hold of 30 to 90 seconds, or the Olympic swimming pool’s depth of just 2.5–3 meters (8–10 feet). But freediving isn’t just a modern marvel; it’s a deeply rooted part of human history.
Roughly 90,000 years ago, Neanderthals were diving to collect clam shells, so frequently that they developed signs of swimmer’s ear, a condition linked to constant exposure to cold water. By 350 BC, Aristotle wrote about sponge divers using lead weights to descend to the seabed. Meanwhile, Japan’s Ama fisherwomen have been freediving for over 2,000 years, harvesting seaweed and shellfish with nothing but lung power.
Perhaps most fascinating of all are the Bajau people of Southeast Asia—a nomadic, sea-dwelling tribe who have spent so many generations underwater, they’ve developed an evolutionary advantage. Bajau divers can spend up to five hours a day underwater, using wooden goggles, body weights, and—remarkably—an enlarged spleen that functions as a natural oxygen reservoir. It’s biology catching up with necessity: a real-life version of evolution crafting a “biological scuba tank.”
#5
Across the seas of Jeju Island, South Korea, the legendary Haenyeo—or "sea women"—have been diving for generations, harvesting abalone, sea urchins, and shellfish from the ocean floor. These women often dive well into old age—and even throughout pregnancy. But what makes them truly unique isn't just cultural—it's genetic.
Recent research reveals that Haenyeo women carry a genetic variant linked to lower-than-average blood pressure. This may offer a key evolutionary advantage: when most humans dive, the body’s vasoconstriction response causes blood pressure to spike—a potential danger during pregnancy. In contrast, the Haenyeo’s genetic adaptation may protect both mother and fetus, allowing them to dive safely through all stages of life.
While the feats of elite and traditional freedivers might seem superhuman, some scientists argue they’re not exceptional outliers—but living proof of a broader biological truth: humans may be natural-born shallow-water foragers, much like otters or beavers.
“Among all known diving mammals, most belong to the shallow-diving group,” explains Erika Schagatay, professor of animal physiology at Mid Sweden University. “Species like beavers, otters, and muskrats forage underwater. Humans fit that profile.”
Like other aquatic mammals, humans exhibit a built-in dive response—a physiological shift triggered by water and breath-hold (apnoea). Upon immersion, the heart rate slows to conserve oxygen, blood vessels constrict in the limbs, and circulation is prioritized to vital organs like the brain and heart. The spleen contracts, releasing a surge of oxygen-rich red blood cells—essentially nature’s own oxygen booster.
In her research, Schagatay analyzes the diving behavior of marine and semi-aquatic species, examining how depth, duration, and cumulative underwater time compare to human performance. Her findings support a growing theory: the ocean may be more deeply embedded in our evolution than we ever imagined.
Born to Dive: The Hidden Biology Behind Human Freediving
Across the seas of Jeju Island, South Korea, the legendary Haenyeo—or "sea women"—have been diving for generations, harvesting abalone, sea urchins, and shellfish from the ocean floor. These women often dive well into old age—and even throughout pregnancy. But what makes them truly unique isn't just cultural—it's genetic.Recent research reveals that Haenyeo women carry a genetic variant linked to lower-than-average blood pressure. This may offer a key evolutionary advantage: when most humans dive, the body’s vasoconstriction response causes blood pressure to spike—a potential danger during pregnancy. In contrast, the Haenyeo’s genetic adaptation may protect both mother and fetus, allowing them to dive safely through all stages of life.
While the feats of elite and traditional freedivers might seem superhuman, some scientists argue they’re not exceptional outliers—but living proof of a broader biological truth: humans may be natural-born shallow-water foragers, much like otters or beavers.
“Among all known diving mammals, most belong to the shallow-diving group,” explains Erika Schagatay, professor of animal physiology at Mid Sweden University. “Species like beavers, otters, and muskrats forage underwater. Humans fit that profile.”
Like other aquatic mammals, humans exhibit a built-in dive response—a physiological shift triggered by water and breath-hold (apnoea). Upon immersion, the heart rate slows to conserve oxygen, blood vessels constrict in the limbs, and circulation is prioritized to vital organs like the brain and heart. The spleen contracts, releasing a surge of oxygen-rich red blood cells—essentially nature’s own oxygen booster.
In her research, Schagatay analyzes the diving behavior of marine and semi-aquatic species, examining how depth, duration, and cumulative underwater time compare to human performance. Her findings support a growing theory: the ocean may be more deeply embedded in our evolution than we ever imagined.
#6
In her research, Professor Erika Schagatay identifies three distinct categories of diving mammals, based on depth, duration, and frequency of dives.
“Deep divers” like sperm whales and elephant seals regularly reach depths beyond 200 meters (660 feet), staying submerged for more than 20 minutes per dive.
“Moderate divers” include sea lions, bottlenose dolphins, and pilot whales, who commonly dive between 10–20 minutes, often reaching around 100 meters (330 feet).
The final group? “Shallow divers”—and this is where humans come in.
Alongside species like otters, beavers, and hippos, humans typically dive to depths of up to 50 meters (165 feet), with most dives lasting less than two minutes.
“Our maximum diving capacity falls right in line with shallow near-shore foragers,” Schagatay writes. Trained humans can repeatedly dive to 20 meters (65 feet), spending up to 60% of their dive sessions underwater—a pattern that mirrors many other mammals in the same group.
Take the Bajau people, for example. Schagatay, who has studied this sea-based community for nearly four decades, describes how they optimize time on the seafloor, diving shallow but frequently, in order to gather seafood efficiently.
“The key,” she explains, “is minimizing surface rest time. The best Bajau divers spend 50–60% of an hour underwater—nearly identical to sea otters. They dive to no more than 20 meters, stay in the shallows, and repeat the process all day. Most people think 20 meters is deep, but with training, anyone can learn to reach that depth. The dive doesn’t even need to last a full minute.”
This repetitive shallow diving ability—combined with adaptations like the dive response, enlarged spleens, and efficient oxygen use—suggests that humans are biologically well-equipped for life in the sea, at least in short bursts.
Still, while humans share the shallow diver category with some seal species, there are notable differences. As Chris McKnight, a research fellow at St Andrews University’s Sea Mammal Research Unit, points out, seals possess specialized adaptations that elevate their performance well beyond what humans can achieve—natural enhancements forged by millions of years of marine evolution.
Humans Among the Shallow Divers: Nature’s Quiet Aquatic Foragers
In her research, Professor Erika Schagatay identifies three distinct categories of diving mammals, based on depth, duration, and frequency of dives.“Deep divers” like sperm whales and elephant seals regularly reach depths beyond 200 meters (660 feet), staying submerged for more than 20 minutes per dive.
“Moderate divers” include sea lions, bottlenose dolphins, and pilot whales, who commonly dive between 10–20 minutes, often reaching around 100 meters (330 feet).
The final group? “Shallow divers”—and this is where humans come in.
Alongside species like otters, beavers, and hippos, humans typically dive to depths of up to 50 meters (165 feet), with most dives lasting less than two minutes.
“Our maximum diving capacity falls right in line with shallow near-shore foragers,” Schagatay writes. Trained humans can repeatedly dive to 20 meters (65 feet), spending up to 60% of their dive sessions underwater—a pattern that mirrors many other mammals in the same group.
Take the Bajau people, for example. Schagatay, who has studied this sea-based community for nearly four decades, describes how they optimize time on the seafloor, diving shallow but frequently, in order to gather seafood efficiently.
“The key,” she explains, “is minimizing surface rest time. The best Bajau divers spend 50–60% of an hour underwater—nearly identical to sea otters. They dive to no more than 20 meters, stay in the shallows, and repeat the process all day. Most people think 20 meters is deep, but with training, anyone can learn to reach that depth. The dive doesn’t even need to last a full minute.”
This repetitive shallow diving ability—combined with adaptations like the dive response, enlarged spleens, and efficient oxygen use—suggests that humans are biologically well-equipped for life in the sea, at least in short bursts.
Still, while humans share the shallow diver category with some seal species, there are notable differences. As Chris McKnight, a research fellow at St Andrews University’s Sea Mammal Research Unit, points out, seals possess specialized adaptations that elevate their performance well beyond what humans can achieve—natural enhancements forged by millions of years of marine evolution.
#7
For humans, the urge to breathe doesn’t come from a lack of oxygen—but from rising carbon dioxide (CO₂) levels. As CO₂ builds up, it alters the blood’s pH, triggering panic in the brain. That instinctual alarm says: Breathe now—or blackout. For freedivers, it’s a hard limit. Cross it, and the consequences can be fatal.
But seals, as Chris McKnight, a research fellow at the Sea Mammal Research Unit at St Andrews University, explains, play by an entirely different rulebook.
Seals aren't nearly as sensitive to CO₂ changes as we are. Instead, they possess a rare ability: they can consciously detect falling oxygen levels in their blood, allowing them to make rational decisions underwater—surfacing before their oxygen runs too low.
“They’re incredible,” says McKnight. “Their heart rate regulation is unmatched. As soon as they dive, their heart can drop from 120 beats per minute to just 4 bpm—in mere seconds. And it stays there until they resurface.”
Even more impressively, seals can adjust their heart rate depending on the dive’s expected duration. If they anticipate a shorter dive, their heart may slow only slightly—to 60 or 40 bpm, for instance.
“This precise cardiovascular control correlates perfectly with the length of each dive,” McKnight adds. “But how they do this? We still don’t fully understand.”
It’s a physiological power far beyond anything the human body can achieve.
“Marine mammals aren’t really part of our world,” McKnight concludes. “They spend the majority of their lives underwater. In a way, they’re true aquatic creatures who occasionally visit our world just to breathe.
It’s the inverse of diving—we go down and return, but they live below and only borrow the air above.”
A Breath Apart: Why Seals Outperform Humans in the Ocean
For humans, the urge to breathe doesn’t come from a lack of oxygen—but from rising carbon dioxide (CO₂) levels. As CO₂ builds up, it alters the blood’s pH, triggering panic in the brain. That instinctual alarm says: Breathe now—or blackout. For freedivers, it’s a hard limit. Cross it, and the consequences can be fatal.But seals, as Chris McKnight, a research fellow at the Sea Mammal Research Unit at St Andrews University, explains, play by an entirely different rulebook.
Seals aren't nearly as sensitive to CO₂ changes as we are. Instead, they possess a rare ability: they can consciously detect falling oxygen levels in their blood, allowing them to make rational decisions underwater—surfacing before their oxygen runs too low.
“They’re incredible,” says McKnight. “Their heart rate regulation is unmatched. As soon as they dive, their heart can drop from 120 beats per minute to just 4 bpm—in mere seconds. And it stays there until they resurface.”
Even more impressively, seals can adjust their heart rate depending on the dive’s expected duration. If they anticipate a shorter dive, their heart may slow only slightly—to 60 or 40 bpm, for instance.
“This precise cardiovascular control correlates perfectly with the length of each dive,” McKnight adds. “But how they do this? We still don’t fully understand.”
It’s a physiological power far beyond anything the human body can achieve.
“Marine mammals aren’t really part of our world,” McKnight concludes. “They spend the majority of their lives underwater. In a way, they’re true aquatic creatures who occasionally visit our world just to breathe.
It’s the inverse of diving—we go down and return, but they live below and only borrow the air above.”
#8
Are we truly limited by our evolutionary design, or can we train ourselves to dive like marine mammals? A growing number of people are now turning to recreational freediving, spurred on by popular Netflix documentaries like The Deepest Breath and My Octopus Teacher.
For Alessia Zecchini – who was featured in The Deepest Breath (2023) – swimming since childhood laid the foundation. At just 13, she began to expand her lung capacity. “I started taking deep breaths and stretching my lungs gradually,” she says. “Now I have two extra liters of lung capacity.” As an adult, Zecchini dedicates hours each day to intense pool and gym sessions. “We can improve ourselves,” she adds.
Yet, Zecchini knows the dangers of freediving firsthand. In 2017, she tragically witnessed the death of her longtime friend and safety diver, Stephen Keenan. During a challenging dive through the 25-meter-long tunnel of Egypt’s infamous Blue Hole – also known as the “diver’s cemetery” – Zecchini became disoriented at a depth of 55 meters (180 feet). Keenan quickly followed to assist her. While both lost consciousness near the surface, only Zecchini survived.
According to the Divers Alert Network (DAN), 2019 recorded just 19 deaths linked directly to freediving, with an additional 31 fatalities involving breath-hold snorkeling. Despite the risks, experts continue to debate the limits of human apneic performance. As researcher Erika Schagatay noted in 2009, “Divers have thus far surpassed all former predictions by physiologists in depth and time.”
In 2021, Schagatay and fellow researcher Dan McKnight studied five elite competitive freedivers. These divers reached depths up to 107 meters (351 feet), with brain oxygen levels even lower than those recorded in seals during their most extreme dives — levels that would normally cause unconsciousness in humans. Astonishingly, their heart rates also dropped to levels typical of whales, dolphins, and seals.
“Our research shows that, at least in part, this is the result of rigorous training,” says Schagatay.
Can Humans Learn to Dive Like Seals?
Are we truly limited by our evolutionary design, or can we train ourselves to dive like marine mammals? A growing number of people are now turning to recreational freediving, spurred on by popular Netflix documentaries like The Deepest Breath and My Octopus Teacher.For Alessia Zecchini – who was featured in The Deepest Breath (2023) – swimming since childhood laid the foundation. At just 13, she began to expand her lung capacity. “I started taking deep breaths and stretching my lungs gradually,” she says. “Now I have two extra liters of lung capacity.” As an adult, Zecchini dedicates hours each day to intense pool and gym sessions. “We can improve ourselves,” she adds.
Yet, Zecchini knows the dangers of freediving firsthand. In 2017, she tragically witnessed the death of her longtime friend and safety diver, Stephen Keenan. During a challenging dive through the 25-meter-long tunnel of Egypt’s infamous Blue Hole – also known as the “diver’s cemetery” – Zecchini became disoriented at a depth of 55 meters (180 feet). Keenan quickly followed to assist her. While both lost consciousness near the surface, only Zecchini survived.
According to the Divers Alert Network (DAN), 2019 recorded just 19 deaths linked directly to freediving, with an additional 31 fatalities involving breath-hold snorkeling. Despite the risks, experts continue to debate the limits of human apneic performance. As researcher Erika Schagatay noted in 2009, “Divers have thus far surpassed all former predictions by physiologists in depth and time.”
In 2021, Schagatay and fellow researcher Dan McKnight studied five elite competitive freedivers. These divers reached depths up to 107 meters (351 feet), with brain oxygen levels even lower than those recorded in seals during their most extreme dives — levels that would normally cause unconsciousness in humans. Astonishingly, their heart rates also dropped to levels typical of whales, dolphins, and seals.
“Our research shows that, at least in part, this is the result of rigorous training,” says Schagatay.
#9
The Bajau people, often referred to as "sea nomads," also exhibit a unique physical trait: enlarged spleens. This is similar to high-altitude populations like the Sherpa, who have adapted to low-oxygen environments. Interestingly, when Sherpas relocate to lower altitudes, their spleens decrease in size – suggesting these adaptations are a result of long-term exposure rather than fixed genetic traits.
Experts have found that the human diving response – which includes lowered heart rate and restricted blood flow to non-essential organs – is highly variable and can be trained. Elite breath-hold divers have shown adaptations such as increased tolerance to hypoxia (low oxygen levels) and hypercapnia (high CO₂ levels), mirroring the responses of seals and dolphins during deep dives.
The allure of the ocean is not just physiological, but deeply emotional. Studies show that "blue spaces" – oceans, lakes, and other bodies of water – can have profound mental health benefits, enhancing mood and reducing stress. This connection to the sea might suggest that humans are not merely land creatures, but also possess an ancient affinity with the water.
"My first dive was when I was seven or eight years old," recalls Alessia Zechinni. "I dove next to a turtle in the Mediterranean Sea." That moment marked the beginning of a lifelong passion. In her book, she reflects: "I decided that the depth of the sea was immensely more fascinating than the surface of the Earth. I left the safety of the surface to dive deeper and explore a world that was so close and yet so profoundly different."
--
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Can Humans Truly Adapt to Life Beneath the Waves?
Recent research suggests that some traits seen in traditional freedivers may not be purely evolutionary but shaped by environmental pressures and training. For instance, the "sea-nomad" children of Thailand – known for their exceptional underwater vision – have developed eyes that function almost like natural goggles, allowing them to see clearly beneath the surface, much like dolphins. Scientists discovered this remarkable skill was not genetic, but trainable, and could even be replicated in European children.The Bajau people, often referred to as "sea nomads," also exhibit a unique physical trait: enlarged spleens. This is similar to high-altitude populations like the Sherpa, who have adapted to low-oxygen environments. Interestingly, when Sherpas relocate to lower altitudes, their spleens decrease in size – suggesting these adaptations are a result of long-term exposure rather than fixed genetic traits.
Experts have found that the human diving response – which includes lowered heart rate and restricted blood flow to non-essential organs – is highly variable and can be trained. Elite breath-hold divers have shown adaptations such as increased tolerance to hypoxia (low oxygen levels) and hypercapnia (high CO₂ levels), mirroring the responses of seals and dolphins during deep dives.
The allure of the ocean is not just physiological, but deeply emotional. Studies show that "blue spaces" – oceans, lakes, and other bodies of water – can have profound mental health benefits, enhancing mood and reducing stress. This connection to the sea might suggest that humans are not merely land creatures, but also possess an ancient affinity with the water.
"My first dive was when I was seven or eight years old," recalls Alessia Zechinni. "I dove next to a turtle in the Mediterranean Sea." That moment marked the beginning of a lifelong passion. In her book, she reflects: "I decided that the depth of the sea was immensely more fascinating than the surface of the Earth. I left the safety of the surface to dive deeper and explore a world that was so close and yet so profoundly different."
--
If you liked this story, sign up for The Essential List newsletter – a handpicked selection of features, videos and can't-miss news, delivered to your inbox twice a week.
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