James Nestor’s Guide to Free Diving

In his book Deep: Free Diving, Renegade Science, and What the Ocean Tells Us About Ourselves, James Nestor explains how he learned to free dive. For Nestor the process was not as simple as just getting into the water and learning to hold his breath. At first he had a real fear of reaching new depths, and this fear held him back from truly being able to free dive and experience the physical and psychological changes that accompany free diving.  One of his free diving coaches was a woman named Hanli Prinsloo who helped Nestor learn to free dive by helping him connect with the ocean in an almost spiritual manner.  Prinsloo turned to her own story to help Nestor understand how to connect to the ocean, and Nestor shares that story in the book. Prinsloo isolated herself from society in a spiritual retreat focusing on philosophy and self awareness through practices such as yoga and conscious breathing. Recounting one of Prinsloo’s personal trips to Dharmsala, India Nestor writes,

 

“At the end of her stay, she rediscovered a “stillness” in herself.  it was the same stillness that had first attracted her to free diving fifteen years earlier, but it had been lost in her ambition to keep going deeper.”
“In Dharamsala, I remembered that free diving was all about letting go,” she says. “After Dahab, I was reminded again, that you can never force yourself into the ocean. You do that and” – she pauses – “you’ll just get lost.”

 

To me, and this was apparent when I first read the quote, the idea of stillness seems to also represent complete self awareness.  Our lives are very busy and rushed, and we often force ourselves into situations that are not always the best. Often times we are pursuing goals both good and bad, and without a moment of stillness we lack the ability to truly reflect on our path and realign ourselves.  When you lose this stillness by constantly seeking an outcome you become lost in what you are doing. There must be stillness as a place for you to stay grounded.

 

Prinsloo’s story shows us the power of connecting with nature, and also the danger in chasing after goals without thinking of how your struggle for those goals affects you and those around you.  Philosophy and self awareness helped Prinsloo to see that by diving for deeper goals she was missing out on enjoying the ocean that she was submerged in.  I think this correlates nicely with our lives in many ways.  It is easy to become so focused on a single area in life to forget about the world, interactions, and relationships that surround us.  Prinsloo needed a moment to step away from her goals and chaos to understand her true desires and see what path she should follow.
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Life in the Ocean

James Nestor wrote the book, Deep: Free Diving, Renegade Science, and What the Ocean Tells Us About Ourselves, after traveling to the Mediterranean to watch a free diving competition.  Prior to the competition he was a certified scuba diver, but it was not until he learned about how the human body reacts to the depths of the ocean without scuba gear that Nestor really began to understand the importance of the ocean.  He did not just study free diving and human physiology in the water, but he worked to understand all aspects of life in the ocean. Nestor writes, “The ocean occupies 71 percent of the Earth’s surface and is home to about 50 percent of its known creatures — the largest inhabited area found anywhere in the universe so far.”

 

I love learning about how large, deep, and diversified our oceans are.  I live in Reno, NV, in one of the only places on Earth that does not have a river that eventually makes its way to the ocean.  Our high desert climate is about as far from the ocean as one can be, which perhaps is why I am so fascinated with the life in water.  Learning about the varied life in the ocean fascinates me because we have only studied the ocean to a very limited extent, and in many ways the deep ocean can be compared to outer space in terms of how difficult it is to reach and the extent to which it has been explored and understood.

 

In Nestor’s quote he writes that the ocean is home to about 50 percent of Earth’s species, and what I find interesting is that many marine biologists believe that we do not know all of the creatures and life forms living in the ocean.  We have truly only explored a small percent of the ocean, and there are many more living organisms to be discovered in the vast depths of the worlds oceans.

 

For me, thinking about the ocean in this way forces me to think about human relationships with the ocean.  Many of our relationships are not positive, through history we have not done a good job thinking about ocean health.  It is easy for our trash to accumulate in watersheds that drain into the oceans, and oil shipping and exploration have had many negative consequences for ocean life.  In addition, we have inhabited huge areas, typically bays and estuaries, along our coastlines and reduced the habitat for many marine species.  While human societies should not be constantly limited in order to save animal species, thinking about how we can live in a state of harmony with oceans and marine life is not just a nice thing to do, it is a necessary responsibility of all humans.

Magnetoreception

James Nestor talks about the incredible abilities of marine animals in his book Deep, and he compares humans, our evolutionary past, and our physical limits to those of marine mammals and other ocean life.  When speaking about diving to incredible depths and perceiving the world he refers to sharks, “Sharks, which can dive below six hundred and fifty feet, and much deeper, rely on senses beyond the ones we know.  Among them is magneto reception, an attunement to the magnetic impulses of the Earth’s molten core.  Research suggests that humans have this ability and likely used it to navigate across the oceans and trackless deserts for thousands of years.”  Nestor explains that at 600 feet below the surface the pressure exerted by the ocean is about twenty times grater than the atmospheric pressure at the surface.  This is the absolute limit of the human body, but other animals, whales and sharks for example, are able to survive these depths.

 

What this section speaks to me about is the incredible diversity in life on our planet. With conservation it is important that we do not force society into blocking projects and developments that may be crucial for societal advances on the basis of preserving natural harmony, but at the same time, seeing the incredible adaptations among all forms of life is inspiring and could unlock new potentials for humanity.  An adaption that leads sharks to be able to navigate by magnetic senses may not directly correlate to human advancement, but understanding that living organisms can adapt these senses may provide a spark of motivation for someone in the future. The possible breakthroughs in science, medicine, and technology are a strong base for expanding education and research of marine life, and that life must be protected through conservation in order for our continued research.  Unfortunately fun discoveries and potential discoveries that could help humanity cannot be considered always more important than a growing and improving society.  Individuals living along the coast rely on shipping, and forcing ports to close by changing shipping lanes so that we can better preserve and save a species of shark to study magnetorecption might not always be the best way to think of conservation.

 

Aside from conservation, what I am constantly reminded of when I read passages that deal with animal senses that seem alien when compared to human abilities, is that we truly do not know everything of our world.  I have come to understand that it is ok to not know everything about the world. It is difficult, but necessary for us to accept that we can not be 100 percent aware of everything around us or everything that influences us.  It is tempting after years of academic work to adopt the idea that one knows everything, can sense everything, and understands their perceptions of the world, but it is a fallacy.  We cannot perceive the world based on our perception of magnetic fields, and keeping that in mind helps us remember that we cannot sense and be aware of all the forces acting on our lives.  I have become comfortable with the idea that there are things that are hidden from me due to my lack of physical senses and mental perspectives.  That comfort helped me to understand that no matter how much I study something or think I know something, there are always different views and ideas that I cannot see which may hide information from me.  Knowing this allows me to listen to others and try to gain more perspectives.  I may not gain a new sense like magnetoreception, but knowing that it exists reminds me to be open.

Our Connection to the Ocean

In his book Deep, James Nestor describes how he became passionate about the oceans, marine life, and our connections to the water as humans.  When he began his research of free diving and started to study marine mammals and our resemblance to marine life, he was surprised. Nestor wrote, “We’re born of the ocean.  Each of us begins life floating in amniotic fluid that has almost the same makeup as ocean water.” Nestor begins with human life as a fetus comparing human embryonic development to that of fish.  “Our earliest characteristics are fishlike.  The month-old embryo grows fins first, not feet.”  As he continues, Nestor spends a lot of time discussing the similarities in our development to that of marine mammals and marine life to show that somewhere in our human past we began life in the ocean, and evolved from life in the ocean.  His position is strengthened when he compares the chemical composition of human blood to sea water, noting the similarities of our blood PH, and he continues the comparison by examining what many call “The Master Switch of Life”, or the mammalian dive reflex.

 

Nestor first encountered the mammalian dive reflex when he watched a group of people exploit our amphibious reflexes to dive to depths of nearly 300 feet in a free diving competition in the Mediterranean.  He was amazed by the capacities of the human body to adjust in water and accomplish things that seemed impossible below the surface, but he was abhorred by the competition aspect of free diving that pushed people beyond their limits and often left competitors bloody and semiconscious.

 

Throughout his book Nestor continually refers back to the idea of human closeness to the ocean. By describing our developmental similarities and evolutional ties to marine life in the quote above, he sets a foundation for the rest of his book that shows how natural free diving and unassisted human exploration of the ocean can be.  He rejects the competition aspect of free diving because it leaves the competitor at a point where they no longer focus on the ocean and their connection to it, but rather push through the water ignoring all senses until they reach a desired depth.  For Nestor, understanding our connection to the ocean means understanding human beings and life in a more intimate way.  Seeing ourselves as evolutionarily bound to the ocean allows him to paint a new picture of the oceans importance for us, and became truly captivating for Nestor who had previously never given the ocean a second thought.

The Mamalian Dive Reflex

A couple of months back I finished the book Deep: Freediving, Renegade Science, and What the Ocean Tells us About Ourselves written by James Nestor.  The author got into the idea and world of free diving after being assigned to cover a free diving competition with divers reaching depths of over 200 feet on just a single breath of air.  The competition is gruesome and not for the faint of heart, but Nestor was captivated.  He did not enjoy the competitive aspect of free diving, but the fact that humans have the ability to stay underwater for over three minutes on a single breath and can become super connected to the ocean while doing so amazed Nestor.  Regarding this incredibly ability Nestor writes, “Scientists call it the mammalian dive reflex or, lyrically, the Master Switch of Life, and they’ve been researching it for the pat fifty years.”

 

What Nestor is discussing when he mentions the Master Switch of Life is the human body’s ability to change its physiological functions while under water unassisted by scuba gear.  But, as Nestor explains, it is not just humans who accomplish this feat. The term mammalian dive reflex is the most accurate because there are many marine mammal species, whales, dolphins, sea lions, who have the same physiological reaction to the icy depths of the ocean that humans do.  If a sea lion can live on the surface and dive hundreds of feet into the the ocean to hunt for food, then clearly life has found a way to adapt to these intense changes of environment. Restricting the mammalian dive reflex to marine mammals seems far more natural than extending the body’s reactions to humans, but Nestor explains what physiological changes take place.

 

During a dive the lungs are forced inwards by the incredibly pressure outside the body and the fact that there is not enough air in the body to hold the lungs out to their normal size.  Around 30 feet down the lungs are half their normal size, and close to 300 feet down they shrink to the size of baseballs.  As this happens our bodies force blood away from our extremities and back towards our chest and brain.  The heart is slowed, but blood is brought back from our arms and legs to make it easier for our heart to pump.  In this state, we can survive the massive pressures of the ocean on just a single breath of air.

 

Nestor also explains that during the dive our lungs change shape so dramatically that if we were to inhale oxygen in a tank filled at normal atmospheric pressures, that air would blast into our lungs so rapidly that the force would burst our lungs. While it sounds terrifying to dive so deeply and not be able to take a breath of air while we are under or as we ascend, it gives the body a unique advantage.  A free diver with their single breath of air can dive incredibly deep and shoot back to the surface as quickly as they would like.  Their body adjusts naturally for the changes in pressure both inside and outside the body, and as soon as the diver breaks the surface they can take a deep breath.  Scuba divers on the other hand must stop to decompress as regular intervals as they ascent from the ocean depths.  This is because the compressed air breathed in under water by divers cannot adjust to the changes of pressure as a diver surfaces.  Nitrogen will bubble out of the blood in a scuba diver if they ascend too quickly, because there will be less pressure on the body and the cardiovascular system to keep the nitrogen dissolved within the blood.  Divers must stop at regular intervals to assure that their body is able to handle the process of pulling nitrogen out of the blood in a safe manner, without it rapidly bubbling up and building up in their joints.  This symptom is called the bends, but it only affects scuba and assisted divers, not free divers. The mammalian dive reflex evolved millions of years ago, and solved the problem that scuba divers must be cautious to prevent.