The Sea People

- The deep blue expands ahead as you walk towards the sea. The salty air that fills your lungs starts to drift away the buzzing noises. You can already feel the changes occurring within you and are only excited to sense more.
As you’ve made yourself comfortable, you are ready to go in, dive under and surround yourself with water. By the minute you’re in, every cell gets nourished and the body experiences an ecstasy rarely lived. -

The first and most common manner of going under water has been around since 4000 B.C., when tribes used to catch fish and gather molluscs through breath-hold diving. To this day, there are still certain cultures that continue this practice and have evolved physiologically to the extent of possessing extraordinary breath-holding abilities. The Bajau people, or “sea nomads,” that live in Southeast Asia are one such population, as well as the women population in Jeju, Korea, known as haenyeo in Korean, or ama in Japanese, which translates into “sea women.”

The Sea nomads spend more than half of their day underwater, hunting and gathering sea life down to 70 meters of depth. The Sea women, on the other hand, keep diving at lesser depths, collecting pearls and scallops in cold water conditions. Both cultures rarely use any specific equipment, other than a few weights and wooden masks, and floating buckets, respectively. Several studies have shown marvellous adaptations acquired through daily long-term immersion that we will get to know today.

Holding the breath, hence staying in apnea, and immersing our face in cold water, affects our brain, body and mind. When we dive, the oxygen consumption lowers through a process called bradycardia. We also have the ability to redistribute the blood flow to the vital organs, such as brain and heart by undergoing peripheral vasoconstriction. Another important physiological aspect is that our spleen, the blood filtering organ, contracts and sends red blood cells, that carry oxygen, into the blood flow, thus prolonging the dive time.

In the case of the abovementioned populations, they have been found to have a bigger mean spleen size due to a genetic mutation of the PDE10A gene that provides a positive functional physiological adaptation to conditions of hypoxia (deprivation of oxygen from the body). Moreover, the exposure to cold water has proved to affect the release of hormones, called catecholamines, by the adrenal glands in Sea women. These hormones, also known as dopamine, norepinephrine and epinephrine, enter the blood flow under physically or emotionally stressful situations. In Ama divers, the concentration of catecholamines under hypoxic and cold water conditions are lower compared to non-divers, suggesting a positive cross-adaptation.

To me, freediving is a way of silencing my mind and relaxing my body to an even higher extent than while practicing yoga or running. When I was living in Italy, I signed up for a freediving course. I could see the progress and changes that occured one session after another. Aside from learning the proper swimming and breathing techniques, I felt better from day to day – I was even more conscious of the lifestyle I was living.

Just before the pandemic hit Italy, we were fortunate enough to visit the deepest pool in the world, located near Padova, in Italy. It was a safe space where we would practice deep diving and learn from one another. I managed to dive to 22 meters depth with ease, several times. And the feeling after was similar to something you experience after a surf session, commonly referred to as endorphin high.

However, apnea is not something to underestimate. There are a handful of physiological responses, from lowered drive to breathe, dizziness or visual troubles, to hypoxia, loss of consciousness, middle ears pressure, hyperventilation and ascent blackout, that can end badly if done improperly and without a buddy that looks after you.

Our body is a powerful machine capable of doing more than we think, but the most important take-home message is to always treat it well and responsibly. Just like the Sea nomads and the Sea women, we are to appreciate it and never seek to go beyond the limits. At the end, enjoyment is what matters.

Inhale. Exhale. Again. And again. And again.

Ilardo, M.A., Moltke, I., Korneliussen, T.S., Cheng, J., Stern, A.J., Racimo, F., de Barros Damgaard, P., Sikora, M., Seguin-Orlando, A., Rasmussen, S. and van den Munckhof, I.C., 2018. Physiological and genetic adaptations to diving in sea nomads. Cell, 173(3), pp.569-580.

Lee, J.Y., Park, J. and Kim, S., 2017. Cold adaptation, aging, and Korean women divers haenyeo. Journal of physiological anthropology, 36(1), pp.1-13.

Tournat, T.Z., 2014. Human adaptations: free divers. UC Merced Undergraduate Research Journal, 7(1).

Y-40 The Deep Joy

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