I am very satisfied that I have a blue mind and a special preoccupation with the ocean.
Unfortunately, I can’t hold my breath underwater for more than a minute. With the added benefit of inhaling pure oxygen beforehand, the average healthy individual not trained for static apnea can hold their breath underwater for a maximum of two minutes.
Now imagine a tribe of humans, an ethnic group that has genetically evolved to survive an average of at least 13 minutes underwater without oxygen. The Bajau Laut people of Southeast Asia have received no special training in modern static apnea, but have been found to have undergone genetic and physiological evolution and acquired new characteristics that make them essentially similar to human seals.
A set of reflex responses known as the diving reflex occurs when the face of an air-breathing mammal is submerged in water. When you’re low on oxygen, your heart rate slows, your spleen shrinks, and your blood vessels constrict. Until you can breathe oxygen again, your body will try to optimize its oxygen supply.
Because it increases the oxygen-holding capacity of the blood and releases red blood cells, the contraction of the spleen is particularly significant.
Gypsies at sea
The Bajau people are a fishing tribe who live on the sea and are nomadic; they spend more than 60 percent of their lives diving deep. According to a 2018 study published in the Journal Cell, they could develop spleens that are almost 50% larger than the average human. This allows them to stay down and maintain their diving reflex significantly longer.
More red blood cells available for deep diving would result from an enlarged spleen. Longer dives would be possible if you had more red blood cells because they would increase your blood’s capacity to hold oxygen. It increases our ability to use the oxygen we breathe.
The Bajau are a subsistence group that inhabits the waterways along the coasts of Malaysia, Indonesia, and the Philippines. They live in long houseboats called lepas. They only visit the city to barter for other goods or to shelter from storms; and hunt for food. The Bajau have spent many ages living at sea, but about 200 years ago some of their people began to settle on land, especially along the coast of Malaysia.
They hunt using a variety of traditional techniques, the most popular of which is diving. They dive to a depth of thirty meters (one hundred feet) using wooden goggles and weights to catch fish for sustenance. They also like to dive for trepang, a specific type of sea cucumber used to prepare soups and other regional specialties.
The researchers found that members of the non-diving tribe also had a genetic abnormality that resulted in an enlarged spleen. They believe the mutation in Bajau may be caused by a specific gene called PDE10A. T4, a thyroid hormone regulated by PDE10A, increases metabolic rate and counteracts low oxygen levels during stressful situations. Larger spleen diameters in mice were associated with T4. Additionally, mice that had altered T4 levels would have smaller spleens.
If it is a hereditary component, your spleen should be a certain size. That’s where we observed this incredibly important difference,” said Melissa Ilardo, lead scientist on the National Geographic research team.
Additional diving-specific genes were discovered in the Bajau that performed various tasks that would not be present in individuals belonging to other closely related ethnic groups.
One of these genes would cause a rush of blood from the limbs and other nonessential components to the heart and lungs when the diving response is activated. Another would protect against the risk of hypercapnia, which is caused by prolonged immersion in water and is characterized by high levels of carbon dioxide in the blood.
Additional adjustments
There is a possibility that the Bajau people exhibit a different physiological adaptation.
Richard Moon is a scientist at Duke University School of Medicine who studies the body’s response to high altitudes and deep depths. Blood fills the pulmonary vessels during deep diving, and if they burst, the victim may not live for several minutes. Moon believes that through consistent training and diving, the walls of the lungs can be strengthened and better prepared to withstand large volumes of blood.
“The chest wall of the lungs can become more flexible. There can be some loosening with training. The diaphragm can stretch. The abdominal muscles can become more flexible. We’re not sure if these things happened,” he said. Said National Geographic [4] “The spleen is capable of contracting to some extent, but we know of no direct connection between the thyroid gland and the spleen.”
The Bajau and Tibetans were found to share this adaptability. Tibetans live on the high plateaus of the Himalayas, which are known as the “roof of the world” due to their amazingly high altitude. Tibetans have developed some special physical adaptations that enable them to live at such altitudes.
The future of hypoxia
Despite their geographic separation, the researchers believe that the Bajau and Tibetans may have experienced severe hypoxia in previous generations. A condition known as hypoxia is defined as a lack of oxygen in the tissues to support body processes [5]. The ancestors of these two ethnic groups likely experienced hypoxia to such an extent that their genes changed to help them cope with it. The Bajau can dive to extremely deep depths underwater, while modern Tibetans are now better able to survive at high altitudes.
It is possible to learn new strategies for managing hypoxia by researching these clans, especially the Bajau.
Lardo claims that the Bajau have a very difficult time adjusting to life in their ancestral homes due to marginalization and segregation. The people who live in the nations where they are located on the coasts and in the seas do not consider them equal. As a result of increased commercial fishing in host countries, thousands have left the ocean. He fears that when scientists get around to studying their adaptations, they may be completely distracted.Â
The Bajau Laut people offer a remarkable example of how humans can adapt to extreme environmental conditions over generations. Their ability to hold their breath underwater for extended periods, thanks to genetic adaptations such as an enlarged spleen, reflects the human body’s potential to evolve in response to its surroundings. These adaptations not only give the Bajau the ability to dive deeper and for longer periods than most humans but also show how ancient human populations may have undergone significant changes to thrive in extreme conditions, such as hypoxia, that both the Bajau and Tibetans faced. . .
Genetic modifications in the Bajau provide key insights into human physiology, particularly the body’s ability to cope with low oxygen levels. By examining the specific genes that allowed the Bajau to excel at deep diving, scientists may unlock new ways to understand how the body responds to and mitigates oxygen deprivation. These findings could have broader implications for medical research, particularly in areas related to respiratory health and the treatment of conditions associated with hypoxia.
Unfortunately, the Bajau face many socioeconomic challenges, including marginalization and displacement, that threaten their way of life. As they are forced from their ancestral homes by commercial fishing and other external pressures, there is growing concern that their unique genetic adaptations may disappear before they are fully studied and understood. Their plight highlights the urgent need to preserve both their culture and the valuable biological knowledge they offer, as their knowledge and traditions may hold the key to advancing the scientific understanding of human adaptability.