Alone with the Depth: Freediving
On January 23, 1960, the Trieste bathyscaphe, with a crew of two people - US Navy lieutenant Don Walsh and Swiss scientist Jacques Picard - reached the bottom of the Mariana Trench. The immersion depth was 35, 800 feet, or 10, 918 m. This record is unlikely to be broken in the foreseeable future - no more depths have been discovered on our planet yet. However, in many respects this record is the merit of the developers (one of which was Jacques Picard) and the builders of the underwater vehicle, and not just the crew. It’s techno divers business - just a man, the sea ... and also a couple of dozens of cylinders with various gas mixtures for breathing at various depths and an immersion plan calculated up to seconds. Each, even ordinary diving to depths of more than 100 m is a many-hour marathon with switching between cylinders and long decompression. The official record for today is considered the achievement of the South African Nuno Gomez, listed in the Guinness Book of Records - 318.25 m (2005). There is also an unofficial record set a little later by the French tech diver Pascal Bernabe - 330 m (2005).
Against this background, the achievements of freedivers may seem much more modest. However, this is only an external impression, and the attitude towards these records changes significantly when you remember that freedivers immerse exclusively in holding their breath, without using either cylinders or breathing apparatus. At the same time, the world record in the deepest category (No Limit) is 214 m for men (Austrian Herbert Nietzsche, 2007) and 160 m for women (American Tanya Streeter, 2002). Russian athlete Natalya Molchanova, 22-times world champion in freediving and holder of current world records in four official nominations (eight in total) of the Association for International Development of Freediving (AIDA), told Popular Mechanics how ordinary people become ichthyander.
“Any healthy person in good physical shape can conquer the 30-meter depth after about a week of intensive training at sea, ” says Natalya. - It will take a year of regular training to conquer 40 meters, two years to 50 meters, and three to 70 meters. But depths over 80 m are the lot of people who have a natural disposition and good motivation. ” From a physiological point of view, freediving is a typical example of an adaptive reaction of an organism. In response to breath holding and lack of oxygen, a decrease in heart rate (bradycardia) by 40–70% (in experienced divers, the pulse decreases to 20 beats per minute). There is an outflow of blood from the peripheral chain to the central one to supply oxygen to only the most necessary organs (heart, brain and individual muscles). In the blood, the number of red blood cells transporting oxygen increases. Lung tissue absorbs blood plasma, swells and becomes almost incompressible, protecting the chest from destruction.
Natural data, such as lung capacity or fitness, are of course important to freedivers. However, psychological preparation plays a much larger role. “The ability to relax and be distracted from everything outside is an integral part of freediving, ” said Natalia Molchanova. - Unlike scuba diving, when we are focused on the outside world, freediving is an immersion in ourselves, it is focused on the inner world. This just makes it possible to complete self-control, which avoids dangers. " The main of these dangers is loss of consciousness, or blackout, due to improper assessment of one's own forces and a drop in the partial pressure of oxygen during ascent. Another danger familiar to ordinary divers is decompression sickness. Although freedivers dive to hold their breath, when diving to large (over 80 m) depths, tissue saturation with nitrogen increases (this is also characteristic of not too deep, but multiple dives). Therefore, now, after record dives, freedivers must undergo decompression - having fulfilled all the requirements of the protocol, they will again dive to a shallow depth (several meters), where they breathe pure oxygen in order to "wash" the accumulated nitrogen.
Is there a limit to the capabilities of the human body? “At one time, freedivers measured a maximum of 50 m, then 100 m, but now a 200-meter mark has already been passed, ” Natalya notes. - The adaptive capabilities of man are still not understood. Most importantly, freedivers change not only their body, but also their worldview: when we don’t breathe and then begin to breathe, we begin to feel more sharply the value of life as a process - regardless of our social or property status. ”
Video to the article: linkThe article was published in the journal Popular Mechanics (No. 9, September 2009).