Freediving

Freediver with monofin, ascending

Freediving, free-diving, or free diving is a form of underwater diving that relies on divers' ability to hold their breath until resurfacing rather than on the use of a breathing apparatus such as scuba gear. Recognised examples of freediving activities include traditional fishing techniques, competitive and non-competitive freediving, competitive and non-competitive spearfishing and freediving photography, synchronized swimming, underwater football, underwater rugby,^[1] underwater hockey,^[2] underwater hunting other than spearfishing, underwater target shooting and snorkeling. The term 'freediving' is often associated with competitive breath-hold diving or competitive apnea. However, while some regard freediving as a specific group of underwater activities, for others it is merely a synonym for breath-hold diving. The activity that attracts the most public attention is the extreme sport of competitive apnea in which competitors attempt to attain great depths, times, or distances on a single breath.

The use of the term to describe breath-hold diving should be recognized as late 20th century in origin, which has been popularly expanded to apply to earlier diving activities. The bibliography of diving history clearly indicates that the term free diving had already been used in the early 1950s by American users of self-contained compressed air breathing equipment (open circuit scuba) to describe their type of diving which is not constrained by connection to a surface air supply, and where the diver has approximately neutral buoyancy and is free to move in three dimensions, although it was probably French in origin, featuring in the title sequence of the Cousteau film Epaves (1943).^[3][4][5]

History

Natural sponges have been harvested by freedivers near the Greek island of Kalymnos since at least the time of Plato.

Freediving was practised in ancient cultures to gather food, harvest resources like sponge and pearl, reclaim sunken valuables, and to help aid military campaigns. 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.^[6] The divers faced the same problems as divers today, such as decompression sickness and blacking out during a breath hold. Because of these dangers, diving in antiquity could be quite deadly.

Freediving for commercial, rather than recreational purposes may have begun in Ancient Greece, since both Plato and Homer mention the sponge as being used for bathing. The island of Kalymnos was a main centre of diving for sponges. By using weights (skandalopetra) of as much as 15 kilograms (33 lb) to speed the descent, breath-holding divers would descend to depths up to 30 metres (98 ft) for as much as 5 minutes to collect sponges.^[7] Sponges weren't the only valuable harvest to be found on the sea floor; the harvesting of red coral was also quite popular. A variety of valuable shells or fish could be harvested in this way creating a demand for divers to harvest the treasures of the sea, which could also include the sunken riches of other seafarers. The Ama Divers from Japan began to collect pearls about 2,000 years ago.^[8][9]

The Mediterranean had large amounts of maritime trade. As a result of shipwrecks, particularly in the fierce winter storms, divers were often hired to salvage whatever they could from the seabed.^[10] Divers would swim down to the wreck and choose the most valuable pieces to salvage. These salvage divers faced many dangers on the job, and as a result, laws, such as the Lex Rhodia, were enacted that awarded a large percentage of the salvage to the divers; in wrecks deeper than 50 feet, divers received one third of the salvage and in wrecks deeper than 90 feet they received half.

Divers were also used in warfare. Defenses against sea vessels were often created, such as underwater barricades aimed at sinking enemy ships. As the barricades were hidden under the water, divers were often used to scout out the sea bed when ships were approaching an enemy harbor. Once these barricades were found it was divers who were used to disassemble them, if possible.^[11] During the Peloponnesian War, divers were used to get past enemy blockades to relay messages as well as supplies to allies or troops that were cut off by the blockade.^[12] On top of all that these ancient frogmen were used as saboteurs, drilling holes in enemy hulls, cutting ships rigging and mooring. [Arrian, Anabasis of Alexander 2.21]

Competition

Competitive freediving is currently governed by two world associations: AIDA International (International Association for Development of Apnea)^[13] and CMAS (Confédération Mondiale des Activités Subaquatiques – World Underwater Federation). Each organization has its own rules on recognizing a record attempt. These can be found on the website from the respective organizations.

Most types of competitive freediving have in common that it is an individual sport based on the best individual achievement. An exception to this rule is the bi-annual World Championship for Teams, held by AIDA, where the combined score of the team members makes up the team's total points. Another exception is the Skandalopetra diving by CMAS.

Disciplines

There are currently eleven recognized disciplines defined by AIDA and CMAS, and a dozen more that are only practiced locally. All disciplines can be practiced by both men and women and, while done outdoors, no differences in the environment between records are any longer recognized. The disciplines of AIDA can be done both in competition and as a record attempt, with the exception of Variable Weight and No limits, which are both solely for record attempts. For all AIDA depth disciplines, the depth the athlete will attempt is announced before the dive; this is accepted practice for both competition and record attempts.

discipline	measurement	AIDA[14]		CMAS[15]		description
		open water	pool	open water	pool
Speed-Endurance Apnoea	min. time	N		–		Speed-Endurance apnoea is an event where the athlete aims at covering a fixed distance at the minimum possible time. The event is swum in fractions of a pool length alternating apnoea swimming with passive recovery at the pool's ends.
STA – Static apnea	max. time					STA is timed breath holding and is usually attempted in a pool.
DYN – Dynamic apnea with fins	horizontal distance	–				For DYN the athlete can choose whether to use bi-fins or the monofin.
DNF – Dynamic apnea without fins	horizontal distance	–				This is underwater swimming in a pool for distance without any swimming aids like fins (AIDA).
The jump blue	horizontal distance	N			–	The jump blue also called "the cube" is a discipline in which an athlete has to descend and swim as far as possible in around a square of 15 meters side situated in a depth of 10 meters.
CWT – Constant weight apnea	depth		–		–	The athlete has to dive to the depth following a guide line that he or she is not allowed to actively use during the dive; only a single hold of the rope to stop the descent and start the ascent is allowed. The ‘Constant Weight’ (French: "poids constant") refers to the fact that the athlete is not allowed to drop any diving weights during the dive. Both bi-fins and monofin can be used during this discipline.
CNF – Constant weight apnea without fins	depth		–		–	CNF follows the identical rules as Constant Weight, except no swimming aids such as fins are allowed. This discipline is the youngest discipline within competitive freediving and is recognised by AIDA since 2003.
FIM – Free immersion apnea	depth		–		–	FIM is a discipline in which the athlete uses the vertical guiderope to pull him or herself down to depth and back to the surface without using ballast or fins. It is known for its ease compared with the Constant Weight disciplines, while the athlete is still not allowed to release weights.
VWT – Variable weight apnea	depth		–		–	VWT is a record discipline that uses a weighted sled for descent. Athletes return to the surface by pulling themselves up along a line or swimming with or without fins.
NLT – No-limits apnea	depth		–	N		NLT is a record discipline that allows the athlete to use any means of breath-hold diving to depth and return to the surface as long as a guideline is used to measure the distance. Most divers use a weighted sled to dive down and use an inflatable bag to return to the surface.
Skandalopetra	depth & min. time	N			–	The athlete dives with the help of a stone (usually a marble slab) attached to a rope. Skandalopetra is a team event: one athlete dives and one is waiting at the surface. When the first athlete reaches the desired depth, the second starts hauling him up.

Monofin freediver holding his breath and swimming underwater

Herbert Nitsch, World Record Holder Freediver

AIDA recognized world records

As of 2 May 2016, the AIDA recognized world records are:^[16]

Discipline	Gender	Depth [m]	Distance [m]	Time	Name	Date	Place
Static apnea (STA)	Men	–	–	11 min 35 sec	Stéphane Mifsud (FRA)	2009-06-08	Hyères, Var, France
	Women	–	–	9 min 02 sec	Natalia Molchanova (RUS)	2013-06-29	Belgrade, Serbia
Dynamic apnea with fins (DYN)	Men	–	281	–	Goran Čolak (CRO)	2013-06-28	Belgrade, Serbia
	Women	–	237	–	Natalia Molchanova (RUS)	2014-09-26	Sardinia, Italy
Dynamic apnea without fins (DNF)	Men	–	226	–	Mateusz Malina (POL)	2014-11-09	Brno, Czech Republic
	Women	–	182	–	Natalia Molchanova (RUS)	2013-06-27	Belgrade, Serbia
Constant weight apnea (CWT)	Men	128	–	–	Alexey Molchanov (RUS)	2013-09-19	Kalamata, Greece
	Women	101	–	–	Natalia Molchanova (RUS)	2011-09-22	Kalamata, Greece
Constant weight apnea without fins (CNF)	Men	101	–	–	William Trubridge (NZL)	2010-12-16	Dean's Blue Hole, Long Island Bahamas
	Women	72[17]	–	–	Sayuri Kinoshita (JPN)	2016-04-26	Dean's Blue Hole, Long Island Bahamas
Free immersion apnea (FIM)	Men	124[17]	–	–	William Trubridge (NZL)	2016-05-02	Dean's Blue Hole, Long Island Bahamas
	Women	91	–	–	Natalia Molchanova (RUS)	2013-09-21	Kalamata, Greece
Variable weight apnea (VWT)	Men	146	–	–	Stavros Kastrinakis (GRE)	2015-11-01	Kalamata, Greece
	Women	130	–	–	Nanja van den Broek (NED)	2015-10-18	Sharm el-Sheikh, Egypt
No-limits apnea (NLT)	Men	214	–	–	Herbert Nitsch (AUT)	2007-06-14	Spetses, Greece
	Women	160	–	–	Tanya Streeter (USA)	2002-08-17	Turks and Caicos

CMAS recognized world records

As of August 2015, the CMAS recognized world records are (Italic records are in waiting approval procedure):^[18]

AIDA equivalent	Discipline		Gender	Depth [m]	Distance [m]	Time	Name/Country	Date	Place	Status	Notes
–	Speed 100 mt. apnea with fins	(no salty water)	Men	–	–	00:36.030	Patric Fourcade (HKG)	2013-08-05	Kazan, Russia	Approved
			Women	–	–	00:43.375	Natalia Ovodova (RUS)	2013-08-05	Kazan, Russia	Approved
STA	Static apnea		Men	–	–	10:18.195	Branco Petrovic (SRB)	2013-08-05	Kazan, Russia	Approved
			Women	–	–	07:30	Veronika Dittes (AUT)	2012-10-01	Antalya, Turkey	Approved
DYN	Dynamic apnea with fins	in Olympic pool (at no salty water)	Men	–	294	–	Alex Duvivier (FRA)	2014-10-17	Mulhouse, France	Approved
			Men	–	265.22	–	Alexsandr Kostyshen (RUS)	2013-08-07	Kazan, Russia	Approved
			Women	–	244.38	–	Ilaria Bonin (ITA)	2014-10-17	Tenerife, Spain	Approved
			Women	–	237.8	–	Ilaria Bonin (ITA)	2013-08-07	Kazan, Russia	Approved
		in 25 mt. pool (at no salty water)	Men	–	200	–	Guerin Boeri (FRA)	2013-08-09	Kazan, Russia	Approved
			Women	–	175	–	Katarina Zubčić (HRV)	2013-11-15	Zagreb, Croatia	Approved
DNF	Dynamic apnea without fins	?	Men	–	?	–	unknown	?	?	?
			Women	–	?	–	unknown	?	?	?
–	Jump blue apnea with fins	(at sea)	Men	–	185	–	Michele Giurgola (ITA)	2012-10-31	Kemer, Antalya, Turkey	Approved
			Men	–	185	–	Xaier Delpit (FRA)	2012-10-31	Kemer, Antalya, Turkey	Approved
			Women	–	168.69	–	Ilaria Bonin (ITA)	2012-10-31	Kemer, Antalya, Turkey	Approved
CWT	Constant weight with fins	(at sea)	Men	94	–	–	Davide Carrera (ITA)	2014-06-22	Isola di Salina, Italy	Waiting approval
			Men	93	–	–	Homar Leuci (ITA)	2012-09-15	Soverato, Italy	Approved
			Women	81	–	–	Alessia Zecchini (ITA)	2013-10-04	Ischia, Italy	Approved
		(at no salty water)	Men	61	–	–	Michele Tomasi (ITA)	2013-09-14	Trento, Italy	Approved ^*
			Men	70	–	–	Michele Tomasi (ITA)	2011-10-02	Trento, Italy	Approved
			Women	57	–	–	Tanya Streeter (USA)	1998-12-28	Ocala, Fl, USA	Approved
CNF	Constant Weight without fins	(at sea)	Men	70	–	–	Morgan Bourc'his (FRA)	2014-06-28	Nice, France	Waiting approval
		(at no salty water)	Men	75	–	–	Michele Tomasi (ITA)	2013-09-14	Trento, Italy	Approved
FIM	Free immersion apnea without fins	(at sea)	Men	81	–	–	Devrim Cenk Ulusoy (TUR)	2012-09-25	Kas, Antalya, Turkey	Approved
			Men	22	–	–	Cem Esmeray (TUR)	2014-07-20	Kas, Antalya, Turkey	Waiting approval	Disabled Athlete
			Women	72	–	–	Şahika Ercümen (TUR)	2014-07-24	Kas, Antalya, Turkey	Waiting approval
			Women	71	–	–	Derya Can (TUR)	2013-10-19	Kas, Antalya, Turkey	Approved
VWT	Variable weight apnea with fins	?	Men	–	?	–	unknown	?	?	?
			Women	–	?	–	unknown	?	?	?
–	Variable weight apnea without fins	(at sea)	Men	81	–	–	Devrim Cenk Ulusoy (TUR)	2012-09-26	Kas, Antalya, Turkey	Approved
			Men	22	–	–	Ufuk Koçak (TUR)	2014-07-23	Kas, Antalya, Turkey	Waiting approval	Disabled Athlete
			Women	91	–	–	Şahika Ercümen (TUR)	2014-07-23	Kas, Antalya, Turkey	Waiting approval
			Women	90	–	–	Derya Can (TUR)	2014-07-20	Kas, Antalya, Turkey	Waiting approval
			Women	71	–	–	Derya Can (TUR)	2013-10-17	Kas, Antalya, Turkey	Approved

^* Michele Tomasi did 61 m at constant weight with fins (at no salty water) on 2013-09-14. This record is approved by CMAS although he already did 70 m on 2011-10-02.

Recreational

Freediving is also a recreational activity, celebrated as a relaxing, liberating and unique experience significantly different from scuba diving. The advantages freediving has over scuba diving are:

• less equipment to wear
• greater mobility and speed
• lower diving costs
• shorter preparation time
• no decompression time for deep dives, because the dive duration is so short. Repetitive deep freedives can result in decompression sickness (Taravana).
• greater visibility (in upwards direction) due to a lack of exhaled air bubbles
• no distracting sounds like regulator breathing (also available when using a rebreather)
• greater time in the water since air tank refills are not needed

Experienced freedivers can often go as deep as scuba divers, and sometimes deeper. Recreational scuba diving is generally limited by diver certification to a maximum of 40 meters, for reasons of safety. Recreational divers who dive to deeper depths are generally expected by the certification agencies to have technical diver training, while freediving is only limited by the divers ability and willingness to accept the risks. Recreational freediving is practiced by many people ranging from the average snorkeler to the professional freediver. Recreational freediving is also frequently practiced in freshwater springs due to excellent visibility.

Freediving into spring caverns and caves is very different from diving in the ocean or other open water (water with an unobstructed vertical access to the surface). Even though every spring cave is unique, these are the general differences:

• A dive light is usually required.
• The freediver must usually swim laterally to exit the cave before ascending to the surface.
• The freediver may also pull on large rocks or the cave structure to enter/exit the cave.
• The freediver must avoid stirring up silt so that visibility is not lost.
• To conserve energy/oxygen, if possible, the current should be avoided while entering the cave, but it can be used to help exit the cave.
• If the freediver is penetrating the cave so far that surface light is lost, proper navigation and passage recognition is vital along with a backup dive light.
• If large air pockets are found inside the cave, they are usually unsafe to breathe from.
• Usually a monofin is impractical to use due to limited space.
• Some cave passages are so small that shorter fins are better to use than long freediving fins.
• The risk of drowning when freediving in an overhead environment is significantly increased. Loss of light, silting, losing the guideline in the dark and any other form of disorientation is likely to have fatal consequences.

The time that a freediver can spend underwater on a single excursion is severely restricted in comparison with scuba, and a considerably greater level of fitness is required for longer breathhold times. A scuba diver generally has sufficient time to recover from a minor disorientating incident in a cave, as there is sufficient breathing gas to perform the recovery procedures. This is not available to the freediver, who has only the oxygen still available in his/her system.

Physiology

The human body has several oxygen-conserving adaptations that manifest under diving conditions as part of the mammalian diving reflex. The adaptations include:

• Reflex bradycardia: Significant drop in heart rate.
• Blood-shift: Blood flow and volume is redistributed towards vital organs by means of a reflex vasoconstriction. Blood vessels distend and become engorged, which in the case of the pulmonary capillaries assists with pressure compensation that comes with increasing diving depth, and without which a largely air-filled chest cavity would simply collapse for lack of compliance.
• Body-cooling: peripheral vasoconstriction results in cooling of peripheral tissue beds, which lower their oxygen demand in a thermodynamic manner. In addition, Murat et al. (2013) recently discovered that breath-holding results in prompt and substantial brain cooling, just like in diving birds and seals. (Dry) breath-holds result in cooling on the order of about 1°C/minute, but this is likely to be greater with cold water submersion, in proportion to the magnitude and promptness of the dive response.
• Splenic contraction: Releasing red blood cells carrying oxygen.

Techniques

Breath-holding ability and, hence dive performance, is a function of on-board oxygen stores, scope for metabolic rate reduction, efficient oxygen utilization, and hypoxia tolerance.^[19] Various athletes attempt to accomplish this in various ways. By and large most divers rely on increasing fitness by increasing lung capacity, by `packing´ and hyperventilating, both of which increase lung oxygen stores.^[20] Needless to say, simple breath-holding is highly effective for increasing lung capacity. In addition, training is allocated to enhance blood and muscle oxygen stores, to a limited extent. A substantial proportion of performance is the result of metabolic suppression and redistribution of blood oxygen stores, the so-called dive response.

Training

Training for freediving can take many forms and be performed on land.

One example 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, the participant then initiates a walk for as far as they can, until it becomes necessary to breathe again. Athletes can do close to 400 meters in training this way.

This form of training is good for accustoming muscles to work under anaerobic conditions, and for tolerance to CO₂ build-up in the circulation. It is also easy to gauge progress, as increasing distance can be measured.

Before competition attempt, freedivers perform preparation sequence, which usually consists of physical stretching, mental exercise and breath exercise. It may include sequention of variable length static apnea, special purging deep breaths, hyperventilation. Result of preparation sequence is slower metabolism, lower heart rate and breath rate, lower level of CO₂ in bloodstream^[21] and overall mental equilibrium. Failing ordinary warning signals or crossing mental barrier by strong will may lead to shallow water blackout or deep water blackout.^[22][23] Trained freedivers are well aware of this and will only dive under strict and first aid competent supervision.^[24] However this does not eliminate the risk of deep or shallow water blackout. All safe freedivers have a 'buddy' who accompanies them, observing from within the water at the surface. Due to the nature of the sport, any practice of freediving must include strict adherence to safety measures as an integral part of the activity, and all participants must also be adept in rescue and resuscitation. Without proper training and supervision, freediving/apnea/breath-hold diving is extremely dangerous. The death of Nicholas Mevoli, a diver from New York, highlights the dangers of freediving. He died on 17 November 2013 after completing a dive to a depth of 72 metres.^[25]

Fiction and documentaries

• The Pearl by John Steinbeck (1947) is a novel about a poor pearl diver, Kino, who finds the 'Pearl of Heaven', which is exceptionally valuable, changing his life for ever. The novel explores themes of man's nature as well as greed and evil.
• In South Sea Adventure (1952) by Willard Price the Hunt brothers, marooned on a coral island, use free diving to collect both pearls and fresh water.
• In Ian Fleming's (1964) James Bond novel You Only Live Twice, the character Kissy Suzuki is an ama diver. This connection was also mentioned in the film version.
• Man from Atlantis was a 1970s TV series which featured a superhero with the ability to breathe underwater and freedive in his own special way.
• The Big Blue (1988) is a romantic film about two world-class freedivers, a heavily fictionalized depiction of the rivalry of freedivers Jacques Mayol and Enzo Maiorca.
• Ocean Men (2001) is a documentary film about the art and science of freediving, featuring two of its most outstanding exponents: Francisco "Pipín" Ferreras and Umberto Pelizzari.
• In the movie Phoenix Blue (2001), protagonist Rick is a musician who freedives competitively.
• The children's novel The Dolphins of Laurentum by Caroline Lawrence (2003), which takes place in ancient Rome, describes the applications of freediving (sponge and pearl diving), and its hazards, as one of the principal characters, as well as the main antagonist, try to beat each other to a sunken treasure.
• The Freediver (2004) is a film about a talented female freediver who is discovered and brought to an island, where she is trained by an ambitious scientist to break a freediving world record currently held by an American woman.
• In the film Into the Blue (2005) starring Jessica Alba, a group of divers find themselves in deep trouble with a drug lord after they come upon the illicit cargo of a sunken airplane in the Caribbean. Jessica Alba is an accomplished freediver, and did much of the underwater work; some other stunts were performed by Mehgan Heaney-Grier.
• In Greg Iles' novel Blood Memory (2005), the main character Cat Ferry is an odontologist and a freediver.
• H₂O: Just Add Water Series 3 added a freediver (Will Benjamin played by Luke Mitchell) as a regular. Freediving is featured in some episodes.
• The Greater Meaning of Water (2010) is an independent film about competitive constant weight freediving, focusing on the 'zen' of freediving.
• In the Canadian television series Corner Gas, the character Karen Pelly (Tara Spencer-Nairn) competed in static apnea, ranking fifth in Canada with a personal best of over six minutes.
• On a long breath (2015) with the quadruple world champion of freediving Pierre Frolla is an invite to share interactions with wild underwater world in the restricted time of an apnea. directed by Philippe Gerard.^[26]
• In the American television series Baywatch episode "The Chamber" (Session 2, Episode 17), the character Mitch Buchannon rescues a diver trapped 90 feet below the ocean surface, but almost dies while suffering the effects of decompression sickness; decompression sickness is highly improbable following freediving exposure to this depth.

See also

• British Freediving Association
• Nordic Deep
• Skandalopetra diving

References

1. "Underwater Rugby on Kinja". Kinja. Retrieved 7 December 2014.
2. "Underwater Rugby on Kinja". Kinja.
3. Dimitri Rebikoff,(1955) Free Diving, Sidgwick & Jackson
4. David M. Owen,(1955)A Manual for Free-Divers Using Compressed Air, Pergamon
5. Tailliez, Philippe; Dumas, Frederic; Cousteau, Jacques-Yves; et. al. (1957) The Complete Manual of Free Diving G. P. Putnam's sons, New York
6. Ivanova, Desislava; Nihrizov, Hristo; Zhekov, Orlin (1999). "The Very Beginning". Human Contact With the Underwater World. Think Quest. Retrieved 2009-09-06.
7. Sandra Hendrikse and André Merks (12 May 2009). "Diving the Skafandro suit". Diving Heritage. Retrieved 2009-10-16.
8. Lundgren, Claus EG; Ferrigno, Massimo (eds). (1985). "Physiology of Breath-hold Diving. 31st Undersea and Hyperbaric Medical Society Workshop". UHMS Publication Number 72(WS-BH)4-15-87. Undersea and Hyperbaric Medical Society. Retrieved 2009-04-16.
9. Rahn, H.; Yokoyama, T. (1965). Physiology of Breath-Hold Diving and the Ama of Japan. United States: National Academy of Sciences – National Research Council. p. 369. ISBN 0-309-01341-0. Retrieved 2009-04-16.
10. Galili, Ehud; Rosen, Baruch (2008). "Ancient Remotely-Operated Instruments Recovered Under Water off the Israeli Coast". International Journal of Nautical Archaeology (Nautical Archaeology Society) 37 (2): 283–94. doi:10.1111/j.1095-9270.2008.00187.x.
11. Frost, FJ (1968). "Scyllias: Diving in Antiquity". Greece and Rome (Second Series) (Cambridge University Press) 15 (2): 180–5. doi:10.1017/S0017383500017435.
12. Thucydides (431 BCE). History of the Peloponnesian War. Check date values in: |date= (help)
13. McKie, N (2004). "Freediving in cyberspace.". Journal of the South Pacific Underwater Medicine Society. 34: 101–03. Retrieved 2013-10-05.
14. AIDA International. "AIDA-disciplines". Retrieved 2015-08-05.
15. Confédération Mondiale des Activités Subaquatiques. "CMAS-disciplines". Retrieved 2015-08-05.
16. AIDA International. "World Records". Retrieved 2016-05-02.
17. "Vertical Blue 2016 results". Retrieved 2 May 2016.
18. Confédération Mondiale des Activités Subaquatiques. "Apnoea Records". Retrieved 2014-07-19.
19. Schagatay E (2009). "Predicting performance in competitive apnoea diving. Part I: static apnoea.". Diving Hyperb Med 39 (2): 88–99. PMID 22753202. Retrieved 2013-10-06.
20. Simpson, G; Ferns, J; Murat, S (2003). "Pulmonary effects of ‘lung packing’ by buccal pumping in an elite breath-hold diver.". Journal of the South Pacific Underwater Medicine Society 33: 122–126. Retrieved 2013-10-06.
21. Neal W. Pollock, Richard D. Vann, Edward D. Thalmann and Claus EG Lundgren. (1997). "Oxygen-Enhanced Breath-hold Diving, Phase I: Hyperventilation and Carbon Dioxide Elimination". In: EJ Maney, Jr and CH Ellis, Jr (Eds.) Diving for Science...1997. Proceedings of the American Academy of Underwater Sciences (17th Annual Scientific Diving Symposium). Retrieved 2009-04-16.
22. Lindholm P, Pollock NW, Lundgren CEG (2006). Breath-hold diving. Proceedings of the Undersea and Hyperbaric Medical Society/Divers Alert Network 2006 June 20–21 Workshop. Durham, NC, United States: Divers Alert Network. ISBN 978-1-930536-36-4. Retrieved 2008-04-30.
23. Lundgren, Claus EG; Ferrigno, Massimo (eds). (1985). "Physiology of Breath-hold Diving. 31st Undersea and Hyperbaric Medical Society Workshop". UHMS Publication Number 72(WS-BH)4-15-87. Undersea and Hyperbaric Medical Society. Retrieved 2009-04-16.
24. Fitz-Clarke, JR (2006). "Adverse events in competitive breath-hold diving.". Undersea Hyperb Med 33 (1): 55–62. PMID 16602257. Retrieved 2013-10-06.
25. Skolnick, Adam (November 17, 2013). "A Deep-Water Diver From Brooklyn Dies After Trying for a Record". The New York Times. Retrieved November 30, 2013.
26. Film description on IMDB : Imdb

Further reading

• Callagy, Feargus (2012) A Beginners Guide to Freediving, e-book published by DeeperBlue.com
• Donald, Ian (2013) Underwater foraging – Freediving for food, Createspace publishing, USA. ISBN 978-1484904596
• Farrell, Emma (2006) One Breath: A Reflection on Freediving, photographs by Frederic Buyle, Pynto Ltd., Hatherley, UK: ISBN 0-9542315-2-X
• Pelizzari, Umberto & Tovaglieri, Stefano (2001) Manual of Freediving: Underwater on a single breath, English translation 2004 by Idelson-Gnocchi Ltd., Reddick, FL: ISBN 1928649270
• Severinsen, Stig A. (2010) Breathology: The Art of Conscious Breathing, Idelson-Gnocchi Ltd., Reddick, FL: ISBN 978-1928649342
• James Nestor (2015) "Deep: Freediving, Renegade Science, and What the Ocean Tells Us About Ourselves", Eamon Dolan/Mariner Books New York, NY: ISBN 978-0544484078

External links

• AIDA International
• Collaborative cartography of freediving spots/Cartographie collaborative des spots apnée (French)
• DeeperBlue website
• DiveWise.Org - non profit organization dedicated to freediving education and safety
• Explore Freediving - Freediving and Snorkeling events and instructor directory
• Freediving Spots
• Borgosub.fr French association to promote Wreck freediving