AIDA LEVEL 3

Question 1

What is the function of blood in the human body?

Answer 1

Transportation of gasses, nutrients, waste products, hormones and body heat;
Protection from inflammation; Regulation of blood acidity (pH), and water balance by transferring water to and from tissues in the body.

Question 2

What is cyanosis and why should you warn your buddy about it?

Answer 2

Cyanosis is also called “blue lips”. As the skin is thinnest on the lips, a change in blood colour due to decreasing level of Oxygen can be easily spotted. However, blue lips can also indicate that the freediver is hypothermic. In both case, it is important to warn your buddy
about it because a freediver cannot feel its own cyanosis.

Question 3

Define diffusion.

Answer 3

Diffusion is the natural tendency of a gas to move from an area of high
concentration to an area of low concentration.

Question 4

Define veins, arteries and the particular case of the lungs circulation

Answer 4

Veins are blood vessels carrying blood towards the heart. Arteries are blood vessels carrying blood from the heart to the organs.
The pulmonary artery is carrying blood low on O2 from the heart to the lungs, while the pulmonary vein is carrying oxygenated blood from the lungs to the heart

Question 5

Hyperventilating does not change the level of Oxygen saturation in the blood, but it decreases its content of CO2. True or False?

Answer 5

True

Question 6

There is a difference between the sensation of pressure-change and pain. Please
comment.

Answer 6

Feeling pressure is essential for an efficient equalisation technique while experiencing pain while diving is always an alarm signal upon which you should stop your descent immediately

Question 7

Why is it not recommended to flush the sinuses with sea water?

Answer 7

Seawater is different from “clean salty water solution”. It also contains pollutants and microorganisms that can cause infections. Try to avoid ingestion of sea water as much as you can, but it is not a problem if it happens on a small basis

Question 8

Regardless of what equalisation technique you are using, what should be the main focus?

Answer 8

Only use the muscles involved in equalisation and relax all others. Tensing the neck or the jaw are common mistakes that can lead to failure of equalisation

Question 9

How do you prevent barotrauma?

Answer 9

You can prevent barotrauma (also called “squeeze”) by eliminating any pressure
differences acting on tissues or organs by equalising the changing pressure. If a
barotrauma occurs, remember these 4 words: “Stay dry, see doctor”

Question 10

What are the symptoms of an eardrum perforation?

Answer 10

sharp pain, vertigo and loss of direction

Question 11

How does a middle ear barotrauma occur?

Answer 11

If you fail to equalise and do not stop your descend, blood and other fluids might be forced into a middle ear, partially or even completely filling it.

Question 12

Why is a suspected middle ear barotrauma to be taken seriously and always be checked by a doctor?

Answer 12

The fluid in your middle ear is a great risk of infection, which can lead to a middle ear infection.

Question 13

Why should you avoid equalising if you are experiencing a reverse block?

Answer 13

equalisation pushes more air into your sinus, but in a reverse block situation there is already too much air in the sinus and/or middle ear. Ascent as slowly as you can, using the rope as a guideline in case you should suffer from vertigo. The trapped air will eventually release

Question 14

What is alternobaric vertigo?

Answer 14

Alternobaric vertigo (AV) is commonly occurring on ascent when one ear depressurises slower (or incompletely) compared to the other. The difference in middle ear pressure can cause the brain to falsely interpret this as bodily movement. Involuntary eye movement, nausea, vomiting, tinnitus and muffled hearing can be symptoms of AV

Question 15

A well fitting hood can be a problem when it comes to hood squeeze. Explain

Answer 15

If the hood seals off very well (which a well fitted hood does!), air that might be trapped in the ear canal between the hood and the ear drum will get compressed on descent and might
cause injury to the ear drum or the ear canal

Question 16

How should you react when experiencing a blocked sinus on descent to avoid a sinus squeeze?

Answer 16

If you experience a sinus block, stop your descent immediately by holding on to the diving line, relax and equalise again. If the pain does not go away you will have to abort the dive and ascent carefully

Question 17

What is the best advice to avoid a sinus block?

Answer 17

do not dive with a cold or congestion and keep well hydrated

Question 18

What is the residual volume?

Answer 18

The residual volume (RV) is the amount of air remaining in your lungs after a maximum exhalation. In average it is 25% of the total lung capacity (TLC)

Question 19

What is the most efficient ways of increasing the vital capacity?

Answer 19

First, practicing proper “one full breath” technique (two-stage inhalation, see AIDA2) will allow you to fill your lungs completely. Second, practice diaphragm stretching will reduce the residual volume and thus increase vital capacity.

Question 20

What is the failure depth?

Answer 20

Failure depth is the depth where residual volume (RV) is reached and normal
equalisation will not work anymore

Question 21

There are several symptoms that indicate a lung injury upon surfacing after a dive. Name at least two of them

Answer 21

You might feel tightness in the chest that does not go away.
Your airways might be
obstructed somewhat, which creates a wheezing sound while breathing. Even after a few breaths
back on surface you have a persisting feeling of difficulty to catch your breath.
You might have the
urge to cough to clear your airways, and if you do so, you are coughing up a pink, foamy liquid.
Last but not least you feel a fatigue that does not go away

Question 22

Give four or more good advices that help to avoid lung squeeze!

Answer 22

Dive with self awareness,
dive relaxed or do not dive,
do not dive if you are
shivering,
Stretch your intercostal muscles and diaphragm,
apply correct forward tumble
turns at depth,
Adapth slowly to depth.

Question 23

Being “too heavy” is obviously dangerous but being “too light” does not always means to be safe in freediving. Please comment

Answer 23

Being weighted to light, you might overexert yourself on the first half of your dive, while you swim down against too much buoyancy

Question 24

Explain and comment on this: “Setting your neutral buoyancy more shallow
does not replace good technique.

Answer 24

Setting neutral buoyancy too shallow means to dive overweighted. But if you have a hard time starting your freedives you need to work on your duck dive technique. Simply taking too many weights on your belt to start your dives is irresponsible and dangerous.

Question 25

If you fall off-balance during freefall, what are your main means to correct that?

Answer 25

Head position in body axis,
Straight body posture,
Even weight distribution on the belt, correct speed,
relaxation of body parts,
Gliding along the line with one hand, other

Question 26

Why is there no benefit in blacking out?

Answer 26

It is not the case that the brain will adapt to work under low Oxygen circumstances
by repeatedly inducing black outs

Question 27

Give examples how a cerebral ischemia can occur

Answer 27

Low blood pressure,
getting up (too) quickly,
hyperventilation leads to cerebral
vasoconstriction,
tight hood in the neck area,
someone is strangling you,
air pocket under the suit,
Others

Question 28

What is the meaning of the term shallow water blackout in freediving?

Answer 28

It means loss of consciousness caused by hypoxia towards the end of a freedive.
The hypoxia is caused or heightened by the changing water pressure when coming up from a freedive

Question 29

Decompression sickness occurred only to divers that breathe compressed air, such as in scuba. True or false? Comment

Answer 29

False. Decompression sickness (DCS) can also affect freedivers, as depth and ascent speed both play a role, not only “bottom time” as in scuba diving

Question 30

What is the “save the legs”-approach

Answer 30

One of the limiting factors in constant weight freediving is the tolerance of the active muscles, mainly the legs, to lactic acid towards the end of a dive. This is the phenomenon of “heavy legs”: Muscles might simply stop to work after reaching the maximum tolerance level of lactic acid. Therefore, warm-up dives should be performed with the least possible physical effort

Question 31

What is the rationale of a CO2 table?

Answer 31

A CO2-table is constructed in way so that the CO2 level in your body increases with each breath-hold.The table allows you enough time between breath-holds to re-establish a good level of O2 in your body, but not enough time to fully offload excess CO2. The
purpose of these tables is to train and increase the tolerance to CO2
both physically and
mentally

Question 32

What is the mammalian dive response (MDR)?

Answer 32

The MDR is a combination of several stimuli triggering a series of reactions that will allow you to conserve oxygen, to use oxygen more efficiently and it will protect you from lung barotrauma

Question 33

Why is the blood shift vital for deep freediving?

Answer 33

When a freediver dives below residual volume (RV), the lungs can still be further compressed because of the blood shift: The blood vessels of the alveoli take up more blood