Rearuh

Freediver with monofin, ascending

Freediving, free-diving, free diving, breath-hold diving, or skin diving is a form of underwater diving that relies on breath-holding until resurfacing rather than the use of breathing apparatus such as scuba gear.

Besides the limits of breath-hold, immersion in water and exposure to high ambient pressure also have physiological effects that limit the depths and duration possible in freediving.

Examples of freediving activities are: traditional fishing techniques, competitive and non-competitive freediving, competitive and non-competitive spearfishing and freediving photography, synchronized swimming, underwater football, underwater rugby, underwater hockey, underwater target shooting and snorkeling. There are also a range of "competitive apnea" disciplines; in which competitors attempt to attain great depths, times, or distances on a single breath.

Historically, the term free diving was also used to refer to scuba diving, due to the freedom of movement compared with surface supplied diving.^[1][2][3]

History

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

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.^[4] The divers faced the same problems as divers today, such as decompression sickness and blacking out during a breath hold. Freediving was practiced in ancient cultures to gather food, harvest resources such as sponge and pearl, reclaim sunken valuables, and to help aid military campaigns.

In Ancient Greece, 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) to collect sponges.^[5] Harvesting of red coral was also done by divers.^{[citation needed]}

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.^[6] Divers would swim down to the wreck and choose the most valuable pieces to salvage.

Divers were also used in warfare. Defenses against sea vessels were often created, such as underwater barricades, and hence divers were often used to scout out the seabed when ships were approaching an enemy harbor. If barricades were found, it was divers who were used to disassemble them, if possible.^[7] 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,^[8] and in 332 BC, during the Siege of Tyre, the city used divers to cut the anchor cables of Alexander's attacking ships.^{[citation needed]}

In Japan, ama divers began to collect pearls about 2,000 years ago.^[9][10]
For thousands of years, most seawater pearls were retrieved by divers working in the Indian Ocean, in areas such as the Persian Gulf, the Red Sea, and in the Gulf of Mannar (between Sri Lanka and India).^[11] A fragment of Isidore of Charax's Parthian itinerary was preserved in Athenaeus's 3rd-century Sophists at Dinner, recording freediving for pearls around an island in the Persian Gulf.^[12]

Pearl divers near the Philippines were also successful at harvesting large pearls, especially in the Sulu Archipelago. At times, the largest pearls belonged by law to the sultan, and selling them could result in the death penalty for the seller. Nonetheless, many pearls made it out of the archipelago by stealth, ending up in the possession of the wealthiest families in Europe.^[13] Pearling was popular in Qatar, Bahrain, Japan, and India. The Gulf of Mexico was also known for pearling.
Native Americans harvested freshwater pearls from lakes and rivers like the Ohio, Tennessee, and Mississippi, while others dived for marine pearls from the Caribbean and waters along the coasts of Central and South America.

In 1940, Dottie Frazier pioneered freediving for women and also began teaching classes. It was also during this time that she began to design and sell rubber suits for Navy UDT divers.^[14]

Freediving activities

Recreational hunting and gathering

Spearfishing

Spearfishing is an ancient method of fishing that has been used throughout the world for millennia. Early civilizations were familiar with the custom of spearing fish from rivers and streams using sharpened sticks.

Today modern spearfishing makes use of elastic powered spearguns and slings, or compressed gas pneumatic powered spearguns, to strike the hunted fish. Specialised techniques and equipment have been developed for various types of aquatic environments and target fish. Spearfishing may be done using free-diving, snorkelling, or scuba diving techniques. Spearfishing while using scuba equipment is illegal in some countries. The use of mechanically powered spearguns is also outlawed in some countries and jurisdictions.^{[citation needed]} Spearfishing is highly selective, normally uses no bait and has no by-catch.

Collection of shellfish

Competitive breath-hold watersports

Aquathlon

Aquathlon (also known as underwater wrestling) is an underwater sport where two competitors wearing masks and fins wrestle underwater in an attempt to remove a ribbon from each other's ankle band in order to win the bout. The "combat" takes place in a 5-metre (16 ft) square ring within a swimming pool, and is made up of three 30-second rounds, with a fourth round played in the event of a tie. The sport originated during the 1980s in the former USSR (now Russia) and was first played at international level in 1993. It was recognised by the Confédération Mondiale des Activités Subaquatiques (CMAS) in 2008.^{[15][16][17][18]}

Competitive spearfishing

Competitive spearfishing is defined by the world governing body CMAS as "the hunting and capture of fish underwater without the aid of artificial breathing devices, using gear that depends entirely on the physical strength of the competitor." They publish a set of competition rules that are used by affiliated organisations.^[19][20]

Synchronised swimming

A member of the Japanese team is thrown up in the air by other members under the water during the team's free routine at the 2013 French Open.

Synchronized swimming is a hybrid form of swimming, dance, and gymnastics, consisting of swimmers (either solos, duets, trios, combos, or teams) performing a synchronised routine of elaborate moves in the water, accompanied by music. Synchronised swimming demands advanced water skills, and requires great strength, endurance, flexibility, grace, artistry and precise timing, as well as exceptional breath control when upside down underwater. During lifts swimmers are not allowed to touch the bottom.^{[citation needed]}

Traditionally it was a women's sport, but following the addition of a new mixed-pair event, FINA World Aquatics competitions are open to men since the 16th 2015 championships in Kazan, and the other international and national competitions allow male competitors in every event. However, men are currently still barred from competing in the Olympics. Both USA Synchro and Synchro Canada allow men to compete with women. Most European countries also allow men to compete, and France even allows male only podiums, according to the number of participants. In the past decade more men are becoming involved in the sport and a global biannual competition called Men's Cup has been steadily growing.^{[citation needed]}

Swimmers perform two routines for the judges, one technical and one free, as well as age group routines and figures. Synchronised swimming is both an individual and team sport. Swimmers compete individually during figures, and then as a team during the routine. Figures are made up of a combination of skills and positions that often require control, strength, and flexibility. Swimmers are ranked individually for this part of the competition. The routine involves teamwork and synchronization. It is choreographed to music and often has a theme. Synchronised swimming is governed internationally by FINA (Fédération Internationale de Natation).

Underwater hockey

Two players compete for the puck in underwater hockey

Underwater Hockey, (also called Octopush (mainly in the United Kingdom)) is a globally played limited-contact sport in which two teams compete to manoeuvre a puck across the bottom of a swimming pool into the opposing team's goal by propelling it with a pusher. It originated in England in 1954 when Alan Blake, the founder of the newly formed Southsea Sub-Aqua Club, invented the game he called Octopush as a means of keeping the club's members interested and active over the cold winter months when open-water diving lost its appeal.^[21] Underwater Hockey is now played worldwide, with the Confédération Mondiale des Activités Subaquatiques, abbreviated CMAS, as the world governing body.^[22] The first Underwater Hockey World Championship was held in Canada in 1980 after a false start in 1979 brought about by international politics and apartheid.^{[citation needed]}

Underwater football

US Navy Students playing underwater football

Underwater football is a two-team underwater sport that shares common elements with underwater hockey and underwater rugby. As with both of those games, it is played in a swimming pool with snorkeling equipment (mask, snorkel, and fins). The goal of the game is to manoeuvre (by carrying and passing) a slightly negatively buoyant ball from one side of a pool to the other by players who are completely submerged underwater. Scoring is achieved by placing the ball (under control) in the gutter on the side of the pool. Variations include using a toy rubber torpedo as the ball, and weighing down buckets to rest on the bottom and serve as goals.^{[citation needed]}

It is played in the Canadian provinces of Alberta, Manitoba, Newfoundland and Labrador, and Saskatchewan.^[23]

Underwater rugby

Underwater rugby is an underwater team sport. During a match two teams try to score a negatively buoyant ball (filled with saltwater) into the opponents’ goal at the bottom of a swimming pool. It originated from within the physical fitness training regime existing in German diving clubs during the early 1960s and has little in common with rugby football except for the name. It was recognised by the Confédération Mondiale des Activités Subaquatiques (CMAS) in 1978 and was first played as a world championship in 1980.^{[citation needed]}

Underwater target shooting

Underwater target shooting is an underwater sport that tests a competitors’ ability to accurately use a speargun via a set of individual and team events conducted in a swimming pool using free diving or Apnea technique. The sport was developed in France during the early 1980s and is currently practised mainly in Europe. It is known as Tir sur cible subaquatique in French and as Tiro al Blanco Subacuático in Spanish.

Competitive apnea

Monofin freediver

Competitive freediving is currently governed by two world associations: AIDA International (International Association for Development of Apnea)^[24] and CMAS (Confédération Mondiale des Activités Subaquatiques – World Underwater Federation). Historically, there were two more organisations that regulated freediving records and activities - IAFD (International Association of Freedivers) and FREE (Freediving Regulations and Education Entity).^[25][26] Each organization has its own rules on recognizing a record attempt which can be found on the organization's website. Alongside competitive disciplines there are record disciplines - disciplines that are not held in competitions, that are just for setting world records. There is a third organization which in addition to AIDA and CMAS preside over those record disciplines and that is Guinness.^{[citation needed]}

Almost all types of competitive freediving have in common that it is an individual sport based on the best individual achievement. Exceptions to this rule are 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 and Skandalopetra diving competitions held by CMAS, the only truly ‘team’ event in freediving - for which teams are formed by two athletes: one acting as an apneista (Voutichtis; diver) and the other acting as an assistant (Kolaouzeris; person who "extracts").

Disciplines

There are currently eleven recognized disciplines defined by AIDA and CMAS, and a dozen more that are only practiced locally.^{[clarification needed][citation needed]} All disciplines can be practiced by both men and women and only CMAS currently separates records in fresh water from those at sea. 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. Most divers choose monofin over bifins where there is a choice.

Discipline	Measure­ment	AIDA[27]		CMAS[28]		Description
		open water	pool	open water	pool
CWT – Constant weight apnea	depth	Y	–	Y	–	Maximum depth following a guide line. The line to act solely as a guide and only a single hold of the rope to stop the descent and start the ascent is permitted. Dropping dive weights is not permitted. Both bi-fins and monofin are permitted.
CWT BF – Constant weight apnea with bifins	depth	N		Y	–	As for CWT above but monofins are not permitted.
CNF – Constant weight apnea without fins	depth	Y	–	Y	–	As for CWT above but no swimming aids such as fins are permitted. This discipline is the most recently recognised discipline having been recognised by AIDA since 2003.
DNF – Dynamic apnea without fins	horizontal distance	–	Y	Y	Y	Maximum distance underwater, in a pool, no swimming aids such as fins are permitted (AIDA).
DYN – Dynamic apnea with fins	horizontal distance	–	Y	Y	Y	Maximum horizontal distance on one breath in a pool. Monofin or bi-fins are permitted, swimming movements with the arms only.
DYN BF – Dynamic apnea with bifins	horizontal distance	N		–	Y	Same as DYN above but monofins are not permitted.
FIM – Free immersion apnea	depth	Y	–	Y	–	Maximum depth following a vertical line. The line may be used to pull down to depth and back to the surface. No ballast or fins are permitted. It is known for its ease compared with the Constant Weight disciplines, while still not permitting the release of weights.
JB – Jump blue, (also the cube)	horizontal distance	N		Y	–	Maximum distance covered around a 15-metre square at a depth of 10 metres. Monofin, bi-fins or no fins are all permitted. Sled may be used for descent.
NLT – No-limits apnea	depth	Y	–	N		Any means of breath-hold diving to depth and return to the surface is permitted provided that a guideline is used to measure the distance. Most divers use a weighted sled to descend and an inflatable bag to ascend.
Skandalopetra	depth & min. time	N		Y	–	The only true team event in freediving. Diver 1 descends, usually assisted by a stone or marble slab attached to a rope, while Diver 2 waits on the surface. Diver 1 reaches the target depth and is hauled to the surface by Diver 2 using only muscle power. No diving mask, suit or fins are permitted, only nose clip.
STA – Static apnea	max. time	Y	Y	Y	Y	Timed breathhold endurance while floating on the surface or standing on the bottom. Usually in a pool.
STA O2 – Static apnea with pure oxygen	max. time	N		N		Timed breathhold endurance, pre-breathing 100% oxygen for up to 30 minutes prior to the breathhold is permitted. Usually in a pool. Although no longer recognised by either AIDA or CMAS there were three instances of records being approved by AIDA.
S&E Apnea – Speed-Endurance Apnea[29]	min. time	N		–	Y	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.
VNF – Variable weight apnea without fins	depth	N		Y	–	Descent is assisted by a weighted sled sliding down a line, the ascent may be by pulling up along the line or swimming without fins.
VWT – Variable weight apnea	depth	Y	–	Y	–	Descent is assisted by a weighted sled sliding down a line, the ascent may be either by: 1.) pulling up along the line or swimming with or without fins under AIDA rules 2.) swimming with fins under CMAS rules.

Herbert Nitsch, World Record Holder Freediver

Overview of the above disciplines ^[30][31][29]

BF - BiFins, MF - MonoFin

World records

Note 1: Best official result in STA is Guinness WR of 11:54 by Branko Petrović in 2014, a freediver who has results in STA over 10 minutes under both AIDA and CMAS.

Note 2: Best NLT result is 253.2m by Herbert Nitsch in 2012; intention of having the dive sanctioned by AIDA fell through due to a sponsoring conflict.

Note 3: After 2001-12-31 AIDA International no longer separated the records achieved in a lake from those in the sea.

AIDA recognized world records

As of 28 September 2017^[update], the AIDA recognized world records are:^[32]

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	–	300	–	Mateusz Malina (POL) &  Giorgos Panagiotakis (GRE)	2016-07-03	Turku, Finland
	Women	–	243	–	Magdalena Solich (POL)	2018-06-29	Belgrade, Serbia
Dynamic apnea without fins (DNF)	Men	–	244	–	Mateusz Malina (POL)	2016-07-02	Turku, Finland
	Women	–	191	–	Magdalena Solich (POL)	2017-07-01	Opole, Poland
Constant weight apnea (CWT)	Men	130	–	–	Alexey Molchanov (RUS)	2018-07-18	Dean's Blue Hole, Long Island Bahamas
	Women	107	–	–	Alessia Zecchini (ITA)	2017-05-10	Dean's Blue Hole, Long Island Bahamas
Constant weight apnea without fins (CNF)	Men	102	–	–	William Trubridge (NZL)	2016-07-20	Dean's Blue Hole, Long Island Bahamas
	Women	73	–	–	Alessia Zecchini (ITA)	2016-04-26	Dean's Blue Hole, Long Island Bahamas
Free immersion apnea (FIM)	Men	125	–	–	Alexey Molchanov (RUS)	2018-07-24	Dean's Blue Hole, Long Island Bahamas
	Women	97	–	–	Sayuri Kinoshita (JPN)	2018-07-26	Dean's Blue Hole, Long Island Bahamas
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	253.2	–	–	Herbert Nitsch (AUT)	2012-06-06	Santorini, Greece
	Women	160	–	–	Tanya Streeter (USA)	2002-08-17	Turks and Caicos

Discipline	Gender	Points	Team / Individual	Date	Place
AIDA team	Men	840.6	CRO Goran Čolak, Božidar Petani, Veljano Zanki	2012-09-16	Nice, France [33][34]
	Women
	Men	313.3	William Trubridge (NZL)	2010-07-06	Okinawa, Japan [35][36]
	Women

CMAS recognized world records

As of 22 October 2017^[update], the CMAS recognized world records are:^[37]

AIDA equivalent	Discipline		Gender	Depth [m]	Distance [m]	Time	Name/Country	Date	Place
–	SPE – Speed 100 m apnea with fins	(50 m pool)	Men	–	–	00:31.710	Stefano Konjedic (ITA)
			Women	–	–	00:35.860	Vera Yarovitskaya (RUS)
–	END 16x50 – Endurance 800 m apnea with fins	(50 m pool)	Men	–	–	09:34.270	Max Poschart (GER)
			Women	–	–	11:20.290	Martina Mongiardino (ITA)
–	END 8x50 – Endurance 400 m apnea with fins	(50 m pool)	Men	–	–
			Women	–	–	4:55.390	Martina Mongiardino (ITA)	2017-04-20	Novara, Italy
STA	Static apnea		Men	–	–	10:39.000	Branko Petrović (SRB)	2015-07-30	Mulhouse, France
			Women	–	–	08:53.150	Veronika Dittes (AUT)
–	Dynamic apnea with fins	(under ice)	Men	–	175	–	Arthur Guérin-Boëri (FRA)	2017-03-11	Lake Sonnanen, Finland
			Women	–	125	–	Valentina Cafolla (CRO)	2017-03-12	Lago Di Anterselva Lake[38]
–		(open water)	Men	–	200	–	Sertan Aydin (TUR)
			Women	–		–
DYN		(50 m pool)	Men	–	300.00	–	Arthur Guérin-Boëri (FRA)	2016-06-11	Lignano, Italy
			Women	–	250.00	–	Alessia Zecchini (ITA)	2016-06-11	Lignano, Italy
	DYN BF – Dynamic apnea with bifins	(50 m pool)	Men	–	246.35	–	Andrea Vitturini (ITA)
			Women	–	204.20	–	Alessia Zecchini (ITA)	2016-06-	Lignano, Italy
DNF	Dynamic apnea without fins	(50 m pool)	Men	–	205.97	–	Goran Čolak (CRO)
			Women	–	171.22	–	Alessia Zecchini (ITA)	2016-06-08	Lignano, Italy
–		(25 m pool)	Men	–	200	–	Arthur Guérin-Boëri (FRA)	2013-08-09	Kazan, Russia
			Women	–	175	–	Katarina Zubčić (HRV)	2013-11-15	Zagreb, Croatia
–	Jump blue apnea with fins	(at sea)	Men	–	201.61	–	Arthur Guérin-Boëri (FRA)	2015-10-09	Ischia, Italy
			Women	–	190.48	–	Alessia Zecchini (ITA)	2015-10-09	Ischia, Italy
		(fresh water)	Men	–	170	–	Alfredo Leonidas Rosado Estrada (ECU)
			Women	–	132.92	–	Gilda Rivadeneria Montalvo (ECU)
CWT	Constant weight with fins	(at sea)	Men	122	–	–	Alexey Molchanov (RUS)
			Women	95	–	–	Alenka Artnik (SLO)
		(fresh water)	Men	80	–	–	Michele Tomasi (ITA)
			Women	57	–	–	Tanya Streeter (USA)	1998-12-28	Ocala, Fl, USA
	CWT BF – Constant weight with bifins	(at sea)	Men	108	–	–	Alexey Molchanov (RUS)
			Women	85	–	–	Alenka Artnik (SLO)  Nataliia Zharkova (UKR)	2017-
		(fresh water)	Men	75	–	–	Michele Tomasi (ITA)
			Women		–	–
CNF	Constant weight without fins	(at sea)	Men	83	–	–	Goran Čolak (CRO)	2017-10-04	Kaş, Turkey
			Women	65	–	–	Nataliia Zharkova (UKR)
		(fresh water)	Men	65	–	–	Michal Rišian (CZE)	2016-07-10	Weyregg, Austria
			Women	–	–	–	–	–	–
FIM	Free immersion apnea	(at sea)	Men	81	–	–	Devrim Cenk Ulusoy (TUR)	2012-09-25	Kaş, Turkey
			Women	72	–	–	Şahika Ercümen (TUR)	2014-07-24	Kaş, Turkey
VWT	Variable weight apnea with fins	(at sea)	Men	131	–	–	Homer Leuci (ITA)	2012-09-11	Soverato, Italy
			Women	111	–	–	Derya Can (TUR)
	VNF – Variable weight apnea without fins	(at sea)	Men	130	–	–	Ufuk Kocak (TUR)
			Women	94	–	–	Derya Can (TUR)
–	Skandalopetra	(at sea)	Men	112	–	–	Andreas Güldner (GER)	2014-06-26	Red Sea, Egypt
			Women	68.9	–	–	Karol Meyer (BRA)	2012	Bonaire, Caribbean

Guinness recognized world records

Note: Only those disciplines that are modifications of existing AIDA or CMAS disciplines and Guinness-exclusive (as it recognizes and inherits some AIDA/CMAS records) or Guinness-conceived (CMAS and AIDA do/did sanction at some time) disciplines.

As of 25 February 2018^[update]

Discipline	Gender	Depth [m]	Distance [m]	Time	Name	Date	Place
STA O2	Men	–	–	24:11	Budimir Šobat (CRO)	24 February 2018	Zagreb
	Women	–	–	18:32	Karol Meyer (BRA)	10 July 2009	Florianopolis
DYN under ice	Men	–	175	–	details under CMAS world records
	Women	–	125	–
DNF under ice	Men	–	84	–	Nik Linder (GER)	Feb 2013	Weissensee [39][40]
	Women	–		–
DNF under ice (no diving suit)	Men	–	76.2	–	Stig Severinsen (DEN)	Apr 2013	Qordlortoq Lake [41][42]
	Women	–	50	–	Johanna Nordblad (FIN)	Mar 2015	Päijänne [43]
NLT under ice	Men	65	–	–	Andreas Pap (SRB)	Feb 2013	Weissensee [39]
	Women		–	–

Recreational

Recreational freediving in Dahab

Freediving as a recreational activity is widely practiced and differs significantly from scuba diving. Although there are potential risks to all freediving, it can be safely practiced using a wide range of skill levels from the average snorkeler to the professional freediver. Compared to scuba diving, freediving offers:^[44]

• Freedom from cumbersome equipment and short preparation times.


• Low cost.


• It is quiet and does not disturb fish, the noise of breathing and bubbles can be quite loud on open circuit scuba though rebreathers are much quieter.


• Mobility and speed, but for a much more limited period.


• No decompression time for deep dives, although it is possible to get decompression sickness, or taravana, from repetitive deep free-diving with short surface intervals.^[45]
  


• The lack of exhaled air bubbles on ascent gives greater visibility on ascent.


• Accessibility, if the site can be walked to it can, potentially, be dived.


• Appropriately skilled and fit freedivers can go as deep, or deeper than, recreational scuba divers, the depth being limited only by the willingness to accept the risks; scuba diving is restricted by the level of certification.

Freshwater springs, often with excellent visibility, provide good freediving opportunities but with greater risks.^{[citation needed]} Diving into spring caverns with restricted access to the surface is very different from diving in open water. The time available to a freediver to solve problems underwater before hypoxia sets in is severely restricted in comparison with scuba. Freediving into confined cave systems such as Eagle's Nest Cave, Florida and Blue Springs State Park, Florida has resulted in several deaths. Cave freediving is commonly discouraged in basic freediver safety training.

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.^{[citation needed]}
  


• 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.^{[citation needed]}
  


• 
  Splenic contraction: Releasing red blood cells carrying oxygen.^[46]
  

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.^[47] Various athletes attempt to accomplish this in various ways. Most divers rely on increasing fitness by increasing lung capacity. Some use "packing", which increases lung volume beyond normal total lung capacity.^[48] Simple breath-holding practice is highly effective for increasing lung capacity.^{[citation needed]} In addition, training is allocated to enhance blood and muscle oxygen stores, to a limited extent.^{[clarification needed]}

Training

Training for freediving can take many forms, some of which can 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, 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]}

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.^{[citation needed]}

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 breath rate, and lower levels of carbon dioxide in the bloodstream^[49] and overall mental equilibrium.^{[citation needed]}

Safety

Hazards

The most obvious hazard is lack of access to air for breathing – a necessity for human life. This can result in asphyxia from drowning if the diver does not reach the surface while still capable of holding their breath and resuming breathing. The risk depends on several factors, including the depth, duration and shape of the dive profile.

Latent hypoxia is a specific hazard of deeper freedives. This effect can cause hypoxic blackout during surfacing.

Risk

Failing to respond to physiological warning signals, or crossing the mental barrier by strong will, may lead to blackout underwater or on reaching the surface.^[9][50] Trained freedivers are well aware of this and competitions must be held under strict supervision and with competent first-aiders on standby.^[51] However, this does not eliminate the risk of blackout. Freedivers are encouraged to dive only with a 'buddy' who accompanies them, observing from in the water at the surface, and ready to dive to the rescue if the diver loses consciousness during the ascent.^{[citation needed]} 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.^{[citation needed]} Without proper training and supervision, competitive freediving/apnea/breath-hold diving is extremely dangerous.^{[clarification needed][citation needed]}

Statistics and notable accidents

Nicholas Mevoli, a diver from New York died on 17 November 2013 after losing consciousness on surfacing from a 3-minute 38 second dive to a depth of 72 metres during an official record attempt in the "constant weight without fins" event. He had previously reached greater depths and longer times in other disciplines.^[52]

Fiction and documentaries

Documentaries

• 
  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.^[53]
  

Fiction

• In the film Mission Impossible - Rogue Nation, Tom Cruise plays super spy Ethan Hunt fighting the forces of evil, and goes freediving in a scene to expose the villains.


• 
  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 forever. 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.


• 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.


• 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 – British affiliate to AIDA International


• 
  Nordic Deep – Freediving competition in Lysekil, Sweden


• 
  Vertical Blue – A freediving competition held annually in The Bahamas at Dean's Blue Hole


• 
  Skandalopetra diving – Freediving using a stone weight at the end of a rope to the surface


• 
  Audrey Mestre – French world record-setting freediver

References

Further reading

• DeeperBlue.com (2016) The Beginners Guide to Freediving, published by DeeperBlue.com
  


• 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

Look up freediving in Wiktionary, the free dictionary.

Wikimedia Commons has media related to Freediving.

• AIDA International


• 
  Collaborative cartography of freediving spots/Cartographie collaborative des spots apnée (in French)
  


• DeeperBlue website


• 
  The Beginners Guide to Freediving - published by DeeperBlue.com


• 
  FreedivingCourses.com - a way to find Freediving instructors and dive centers around the world


• 
  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