Freediving: Difference between revisions

In ancient times freediving without the aid of mechanical devices was the only possibility, with the exception of the occasional use of reeds and leather breathing bladders.<ref name="Desislava et al 1999" /> The divers faced the same problems as divers today, such as [[decompression sickness]] and [[Freediving blackout#Ascent blackout|blacking out]] during a breath hold. Freediving was practiced in [[Classical antiquity|ancient cultures]] to [[fishing|gather food]], harvest resources such as [[sponge]] and [[pearl]], [[Marine salvage|reclaim sunken valuables]], and to help aid [[military campaign]]s.

| align="left"| Timed breathhold endurance while floating on the surface or standing on the bottom. Usually in a pool.

| align="left"| Shortest time over a fixed, underwater distance. An endurance sub-discipline is swum in fractions of a pool length alternating apnoea swimming with passive recovery at the intervals. Disciplines are '''SPE''' – 100m speed apnoea, '''END 16x50''' – 800m and '''END 8x50''' – 400m endurance apnoea.

|rowspan="2"|DNF under ice (no diving suit)|| bgcolor="#c2ebf5"|Men ||– ||81 ||– ||{{Flagathlete|[https[://cs.wikipedia.org/wiki/:David%20Vencl Vencl|David Vencl]]|CZ}} ||Feb 2021 ||Lahošť lake

Most divers rely on increasing fitness by increasing {{CO2}} tolerance and lung capacity. Simple breath-holding practice is highly effective for the build-up of tolerance to [[Carbon dioxide|CO₂]] and to some degree increased lung capacity. In an interview on the radio talk show [[Fresh Air]], journalist James Nestor, author of the book ''[[Breath: The New Science of a Lost Art]]'',<ref name="Nestor 2020" /> stated: "Some divers have a lung capacity of 14 liters, which is about double the size for a typical adult male. They weren't born this way. ... They trained themselves to breathe in ways to profoundly affect their physical bodies."<ref name="Gross" />

Training for freediving can take many forms, some of which can be performed on land. The [[University of Miami]] presents a scientific freediving class that was developed by [[Claire Paris]], a professormarine scientist and freediver,<ref>{{Cite web|title=RSMAS General (RSM) < University of Miami|url=https://bulletin.miami.edu/courses-az/rsm/|access-date=2021-10-16|website=bulletin.miami.edu}}</ref> the class is the first of its kind at the university.<ref>{{Cite web|last=Tannen|first=Janette Neuwahl|date=October 23, 2020|title=Oceanographer finds solace under the surface|url=https://news.miami.edu/stories/2020/10/oceanographer-finds-solace-under-the-surface.html|access-date=2021-10-16|website=news.miami.edu|language=en}}</ref><ref name=":2">{{Cite web|last1=Paris|first1=Claire|last2=Paris|first2=Ricardo|date=August 1, 2020|title=Freediving for Science|url=https://dan.org/alert-diver/article/freediving-for-science/|access-date=2021-10-16|website=Divers Alert Network|language=en-US}}</ref>

One exampletraining exercise is the apnea walk. This consists of a preparation "breathe-up", followed by a short (typically 1 minute) breath hold taken at rest. Without breaking the hold, participants then begin walking as far as possible until it becomes necessary to breathe again. Athletes can do close to 400 meters in training this way.{{citation needed|date=September 2014}}

This form of training is good for accustoming [[muscle]]s to work under [[Hypoxia (environmental)|anaerobic]] conditions, and for tolerance to [[carbon dioxide|CO₂]] build-up in the circulation. It is also easy to gauge progress, as increasing distance can be measured.{{citation needed|date=May 2017}}

Before competition attempts, freedivers perform a preparation sequence, which usually consists of physical stretching, mental exercise and breath exercise. It may include a succession of variable length static apnea and special purging deep breaths. Results of the preparation sequence are slower metabolism, lower heart rate and breathbreathing raterates, and lower levels of carbon dioxide in the bloodstream,<ref name="aaus1997" /> and overall mental equilibrium.{{citation needed|date=August 2017}}