Deep: Freediving, Renegade Science, and What the Ocean Tells Us About Ourselves by James Nestor
We all know that I naturally pick up any book about the ocean, whales, sharks, squid, octopuses, waves, etc. So, no surprise that I read James Nestor's forthcoming book, Deep: Freediving, Renegade Science, and What the Ocean Tells Us About Ourselves. I didn't know anything, really, about freediving before I read this - and any preconceived notions I might have had were firmly smashed.
"In freediving, the ego is a deadly goad."The sport of freediving involves diving into the ocean as deep as you can on one single breath. That's pretty much it. There are several categories of diving - some with fins, with weights you drop, a weighted sled you ride to the bottom. The purists use nothing - no fins, weights, ropes - just a big 'ol breath. (The current world record-holder is William Trubridge at 331 feet.) The dramatically-soundtracked video above is of freediver Guillaume Nery diving into Dean's Blue Hole in the Bahamas. Nery definitely subscribes to the more respectful, introspective, philosophical side of freediving, even if he's a competitor. Granted, there's certainly a subset of freedivers out there who are in the sport for the competition, the world-records, and the fame, such as it is. There are also plenty of fools out there who push their unprepared bodies and minds far beyond their limits, essentially breaking themselves trying to dive deeper. But there's a far more harmonious, meditative element to diving without air to the bottom of the sea - and this is what the takeaway from Deep is.
Here's some of what I learned:
- First of all there's the "mammalian dive reflex" or the Master Switch of Life. This is the set of physiological reflexes that trigger whenever we put our faces in water. We are actually hardwired to be able to hold our breath and dive underwater to great depths, even though for most of us, that reflexive ability lies dormant. "The deeper we dive, the more pronounced the reflexes become," Nestor says, "(keeping our) organs from imploding... and (turning) our bodies into efficient deep-sea-diving systems." Humans are naturally able to survive diving into ocean depths of 300 feet (and deeper) without the aid of airtanks and submarines - we just need to re-stimulate the reflexes.
- By slowly diving without pressurized air in our lungs (like from a scuba tank) nitrogen doesn't build in our blood and give us the bends. We're A-okay once we come to the surface again. Most of the time - and if we've done things right. We also are capable of holding our breath for 10-15 minutes. Yes, even you.
- At 100 feet down, our heart rate slows to half its normal rate and blood begins to leave the extremities and circulate the important areas in our core. (See Lynne Cox.)
- We can also learn to echolocate - like a dolphin, using clicks to map the world around us. Like this guy.
- Some sharks can detect 2 billionths of a volt in the water. This is like dropping a 1.5-volt battery into the Hudson River, running a wire from the battery up to Portland, Maine, and being able to detect the charge coming off the wire.
- Sperm whale clicks can reach a maximum level of 234 decibels. "The noise level in air maxes out at 194 decibels," Nestor writes. Anything louder than that turns into a pressure wave. "The threshold of noise in water is 240 decibels; any louder, and the noise will almost literally boil the liquid into vapor..." Basically, sperm whales are loud enough to explode your head.
- The "ama" are an ancient culture of Japanese women who dive like freedivers to gather food on the ocean floor. After searching and searching, Nestor finally tracked down a small group of modern-day ama in Shimoda, Japan who dive 40-50 times an outing on single breaths. They tell him the ancient secret is, "You just dive."
Nestor certainly writes with a journalist's eye - until he reaches that point where he starts wondering about his own Master Switch. (This happens almost immediately, while covering a freediving competition for Outside magazine.) He then really hits a rhythm and this becomes more of an obsessive quest to unlock the secrets of the deep and figuring out what our place is down there. His inherent, inquisitive human nature takes hold and we're right along with him, swimming with huge whales, freediving to the point where gravity drags you deeper, riding in a homemade submersible to unfathomable depths. I just found it all so fascinating that we have this innate ability to hold our breath and dive deep that most of us are not aware of. "What are we?" Nestor asks on the last page. Deep-swimming mammals, I guess. Freediving, master switches, blue holes, sperm whale clicks - it all kind of scares the hell out of me. But part of me wants to try flipping that switch to see how deep I can go....