Freediving terms

Here you find the most commonly used terms in freediving.

Term Definitions
A.I.D.A. Association Internationale pour le
Développement de l’Apnée – one of the main international freediving agencies
aerobic Cellular metabolism with oxygen,
requiring oxygen for breathing
air embolism Obstruction of the circulatory
system caused by an air bubble as e.g.  as a complication from scuba diving [syn: aeroembolism] 2: pain
resulting from rapid change in pressure [syn: decompression sickness,
aeroembolism, caisson disease, bends]
anaerobic Not aerobic  –  not needing or without oxygen –  an activity in which the body incurs an oxygen debt
anaerobic metabolism Creation of energy through the
combustion of carbohydrates in the absence of oxygen.

This occurs when the lungs cannot
put enough oxygen into the bloodstream to keep up with the demands from the
muscles energy. Generally  used
for short busts of activity

apnea From the Greek, it means
“without, or not breathing”.
ascent bo Blacking out while ascending from
a dive, if it happens, it’s usually in the last 10 – 15 meters
ascent rates Speed at which one ascends from a
barotraumas An injury that results due to
rapid or extreme changes in pressure.
bi-fins Traditional swimming fins – one
for each foot
blackout Losing consciousness during
breath-hold activities
blood pH Level of acidity/alkalinity in the
blood shift Related to the mammalian diving
reflex – to prevent collapse under great pressure, the wall of the lungs fill
with blood from other parts of the body.
bo See: Blackout
bottom time Time spent underwater during a
dive while freediving, or the time spent lingering at the bottomweight/plate
bradycardia Part of the mammalian diving
reflex: Slowing down of the heart rate and pulse
breathing oxygen Breathing pure oxygen as a
therapeutic measure or as a preparation for increasing one’s time underwater.
breath-up Set of breathing procedures done
before a long immersion – used to build up the capacity of the body in order
to spend more time underwater on a single breath.
carp breathing See: Packing
certifying agencies Official freediving agencies that
have the authority to certify the different local, national and world
freediving records.
clogged ear Having the ear canal of the outer
ear obstructed, also called swimmers ear.
CMAS CMAS is an international
organisation to promote SCUBA diving and other underwater sports. Founded by
J.Y. Cousteau
CO2 narcosis Toxicity resulting from too high
levels of carbon dioxide in the blood
CO2 tolerance Tolerance to carbon dioxide in the
collapsed lung A collapsed lung, or pneumothorax,
involves the collapse of the tissues of part or all of one lung so that
oxygen cannot be absorbed into the blood stream in the normal way. Changes in
pressure during diving may cause tissue damage. See also: pneumothorax
constant ballast See: Constant weight
constant weight One of the freediving disciplines:
Diving down as deep as one can and ascending without the use of any
mechanical device and rope. The weight of the freediver must remain the same
during descent and ascent.
contractions After a certain time without
sufficient oxygen, the diaphragm starts to flutter and also experience
contractions in order to “remind” the body that it needs to breath.
countdown time The time just prior to a dive or
static apnea. It is usually called out in a competition to help freedivers
time their preparation and breath-up prior to the dive.
cramps A sudden and involuntary
tightening of a muscle – usually can be quite painful. Cramps usually happen
in the legs for swimmers and freedivers.
Crazy Cuban Diving as deep as possible with no
aids whatsoever – no mask, fins, or weight belt. Also favoured by the
freediver Sebastian Murat.
DCI See: decompression sickness.
Acronym for Decompression Illness
DCS See: decompression sickness
decompression Procedure used by scuba divers to
reabsorb the nitrogen that has built up in the blood stream during long and
deep dives
decompression chamber A pressurized chamber used to
reproduce the pressures found at great depths. Usually used to help divers
recover from decompression sickness.
decompression sickness Physiological disorder caused by a
rapid decrease in atmospheric pressure, resulting in the release of nitrogen
bubbles into the body tissues. It is also known as caisson disease, altitude
sickness, and the bends
DEMA Dive Show Diving Equipment & Marketing
Association – Trade fair organization
depth adaptation The capacity of the lungs to adapt
to the pressure found at great depths.
dive computers Computer that can measure the
depth and time spent at each depth. It also calculates the recommended
decompression times needed by the diver.
diving response Lowering of the heart rate and
constriction of the blood vessels in the body causing blood to be redirected
to the brain and heart to keep the important vital functions active.
dizziness Disorientation of the sense of
balance – vertigo.
dry static Static apnea on dry land.
dynamic apnea (with fins) One of the disciplines of  freediving: swimming underwater as
far as one can with fins.
dynamic apnea (without fins) One of the disciplines of  freediving: swimming underwater as
far as one can without any type of fins.
ear jamming When the Eustachian Tubes close
and no amount of pressure seems to open them during a dive
embolism See: Air embolism
empty lung dives Refers to “negative pressure
dives” where freedivers prepare their lungs for very deep dives by
emptying them of air and diving several meters. The lack of air pressure in
the lungs simulates diving to a much greater depth and is useful as a warm up
equalization Balancing the air pressure in the
middle and outer ear.
equalize The act of equalizing the pressure
difference between the middle and outer ear. There are several techniques.
The two main ones are the Valsalva and the Frenzel techniques.
Eustachian tube A tube that connects the middle
ear with the nasopharynx and permits the equalization of pressure on both
sides of the eardrum. It is bony and cartilaginous.
F.R.E.E. Freediving Regulations &
Education Entity – Freediving teaching agency, less active
failure depth, breakpoint The depth where lung pressure
turns negative and below that it is difficult -or impossible- to bring air in
the mouth for equalization
fire breathing Slow shallow breathing, slowed by half closing
epiglottis. The idea is to keep a nearly continuous ‘greater-than-ambient’
pressure in the lungs.
fluid goggles Diving mask containing liquid
instead if air to avoid using up valuable air equalizing the mask at depth.
May have corrective lenses to adjust for the liquid the eyes have to see
free ascent dangers The dangers of ascent, could be
decompression sickness (rare in freedivers), shallow water blackout (most
common danger), and overstretching of the lungs after having packed allot.
(Also very rare)
free immersion One of the disciplines of
freediving: diving as deeply as one can without fins and pulling one’s self
down and up a guide rope.
freediving The fine art of diving without
using any breathing apparatus. Freediving can be competitive or recreational.
Frenzel Technique Equalization technique involving
using the tongue as a piston to force air through the Eustachian Tubes.
haemoglobin Protein in the red blood cells
which combines with and carries oxygen around the body, and gives blood its
red colour
heavy packing Packing allot of air into the
lungs – some freedivers can pack up to 4 liters of extra air into their
HMS Dolphin A special 30 meter deep swimming
pool in the UK designed for training submariners to escape from a submarine
at 30 meters on a single breath. Freedivers can also use the HMS Dolphin
paying a fee.
hook breathing Taking a deep breath after a long
breath–hold and bearing down on it for a couple of seconds to speed up the
transfer of oxygen from the lungs to the rest of the body as well as to force
blood up to the head and keep the O2 moving.
hyperbaric chamber A pressurised chamber that allows
for the delivery of oxygen in higher concentrations for therapeutic benefit –
useful for decompression illness
hyperbaric oxygen therapy The therapeutic intermittent
administration of oxygen in a chamber at greater than sea-level atmospheric
pressures (three atmospheres). It is considered effective treatment for air
and gas embolisms as well as for decompression illness.
hypercapnia Too much carbon dioxide in the
hyperoxia Too much oxygen in the blood
hyperventilation Hyperventilation is the practice
of excessive breathing with an increase in the rate of respiration or an
increase in the depth of respiration, or both
hypocapnia Lower than normal carbon dioxide
in the blood stream, can result from hyperventilation and bring on blackout
sooner than normal.
hypothermia When a person’s body temperature
falls below normal due to exposure to extreme cold. This is a dangerous
condition that can result in death.
hypothermic diving system System devised by Eric Fattah
taking advantage of steep thermoclines to induce hypothermia therefore
increasing the diving reflex to be able to dive deeper.
hypoxemia Lower than normal oxygen in
arterial blood which gives rise to hypoxia.
hypoxia Lower than normal oxygen supply to
tissues even though there might be a proper amount of blood in the tissues.
IAFD International Association of Free
Divers – Freediving teaching Agency, less active
lactic acid Lactic acid is a by-product of
anaerobic glycolysis and anaerobic metabolism. Although used as a fuel by the
heart, excessive lactic acid slows down contractions of the skeletal muscles,
preventing you from walking fast
LMC Loss of Motor Control – also known
as “samba”. It occurs when the muscles have almost no oxygen and
suffer seizures. It happens just before blackout.
lung fluid Fluid i.e. plasma filling the
walls (alveolis) of  your lungs
is a response to the increased pressure at depth (usually at around 50m but
it can vary quite a bit depending how much air you have in your lungs and
your residual volume) to protect your lungs and other organs.
Lung packing See: Packing
lung squeeze See: pulmonary edema.
lung training Training the lung to have more
strength and capacity
lung volume Amount of air in the lungs, also
known as TLC
mammalian diving reflex See: diving response
mask air The amount of air in the mask.
There are high–volume and low–volume masks. Freedivers prefer low–volume air
as they are easier to equalize.
mask pumping Technique for utilizing the air in
one’s mask during ascent. See: rebreathing
mask volume See: Mask air
Middle-Ear Barotrauma Middle–Ear problems due to quick
changes in pressure. It can happen on ascent when the pressure in the outer
ear diminishes faster than in the inner ear. Also known as “reverse
monofins Fins based on the design of a
dolphin’s tail. Both feet fit into a single monofin. Even though hard to use
at first, they provide greater power and speed than bi–fins.
N2 narcosis See: nitrogen narcosis
narcosis See: nitrogen narcosis
negative pressure dives See: Empty lung dives
newbie Someone new to a particular
activity, a beginner
nitrogen narcosis Mental state similar to euphoria,
drunkenness and disorientation caused by the narcotic effects of the air’s
nitrogen at high pressure. Divers often exhibit dangerous behaviour such as
ditching equipment underwater. Also known as rapture of the deep.
no limits One of the disciplines of
freediving: Descending as far as possible with ballast equipment (usually a
sled) and ascending with an air balloon or similar.
nose clip Device that closes the nostrils to
prevent water getting in or air getting out.
O2 levels Levels of oxygen in the blood
oxygen narcosis See: oxygen toxicity
oxygen toxicity Occurs when one breathes high
partial levels of oxygen in the blood stream. Symptoms can be deep fatigue
while breathing, muscular twitching, anxiety, confusion, incoordination, and
convulsions including visual and auditive abnormalities
pack stretching Stretching of the lungs due to
packing Special techniques for filling the
lungs with more air than normally possible.
PaCO2 Partial pressure of arterial
carbon dioxide in the blood
PB Acronym for “Personal
peripheral vasoconstriction It has been shown that at depth,
blood flow is shunted from the limbs to those organs whose oxygen consumption
is critical, the heart and brain
personal bests One’s best record in any of the
disciplines of freediving
pipe mask Diving mask with a small tube
extending from the mask to mouth for equalizing.
pneumothorax A condition in which air or other
gas is present in the pleural cavity and which occurs spontaneously as a
result of disease or injury of lung tissue or puncture of the chest wall or
is induced as a therapeutic measure to collapse the lung. See also: Collapsed
Powerlung Training instrument used for
enhancing lung capacity.
pranayama Yogic breathing techniques for
balancing and enhancing the body’s vital energies.
pulmonary edema Dangerous medical condition where
the lung fills with increased interstitial fluid causing the alveoli to flood
with the fluid and be coated in blood, thus reducing the alveoli’s capacity
to transfer oxygen.
rebreathing In relation to freediving: Sniffing
or rebreathing the expanding air in one’s mask while ascending. Also known as
“mask pumping”
recreational freediving Freediving for pure and simple
residual lung volume (RV) The volume of air that remains in
the lungs after exhaling completely
Reverse Squeeze See: Middle–Ear Barotrama
RV See: Residual lung volume
S.A.F.E.R. “Specialized Advanced
Freediving Enhancement & Reliability ” –  Freediving teaching agency, less active
samba Loss of muscle control commonly
known as “samba”,  preceding
blackout in many cases.
SaO2 Saturation of Oxygen (arterial
security rope Guide rope or line used to orient
the freediver while descending, also known as the rope or the diverope.
shallow water blackout Sudden loss of consciousness
caused by pressure drop in oxygen.
skindiving Swimming underwater or on the
surface usually with the help of a face mask, fins, and a snorkel
solo freediving Freediving alone without a buddy
spirometer Medical instrument used to measure
vital lung capacity
spotting Having a buddy watch you for
safety reasons while engaging in freediving activities either in the swimming
pool or the sea.
static apnea One of the disciplines of
freediving: Seeing how long one can hold one’s breath while floating on the
surface with the face submerged.
suit squeeze “Suit squeeze”, where
the hood of a stretchy wetsuit ‘seals’ around the outer ear, trapping air in
the outer ear. This can cause problems due to incorrect equalizing on descent
or ascent.
surface intervals Time spent at the surface between
SWB See: Shallow water blackout
tear duct equalization Equalization (of the mask?)
through the tear ducts
tidal volume The volume of air normally inhaled
or exhaled when one is making no extra effort.
TLC See:Total Lung Capacity
total lung capacity (TLC) Total Lung Volume: The sum of RV
and VC
variable ballast One of the freediving disciplines:
Going down with a weighted device and coming up pulling on a rope or swimming
vasoconstriction See: peripheral vasoconstriction
VC See: Vital Capacity
ventilation More than normal breathing, less
than hyperventilation.
vital capacity (VC) The amount of air of a complete
and full exhalation including the expiratory reserve volume
warm ups Preparative exercises previous to
an activity requiring great physical effort. Usually different kind of dives.
weight belt ditching Releasing the weight belt
weighting Applying the correct amount of
weight for one’s freediving or scuba needs
weights Usually lead weights used for
counteracting the body’s (and wetsuit’s) natural buoyancy.
wet lung Also known as Pulmonary Edema: The
abnormal accumulation of liquids in the lungs due to rapid changes in
pressure. Different from lung fluid, this is harmful and can lead to
secondary drowning.
wet statics Static apnea in the pool or sea