Wednesday, September 30, 2020

Freediver Safety & Static Tables – Part I

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THE PURPOSE of this series of articles is to address the value to the freediving community of a Winter Freediving Program suited to the BEGINNER or INTERMEDIATE student. When summer arrives and freedivers once again have access to warm water they ought to be in the BEST condition possible.

The primary emphasis must be safety: knowing what the dangers are, how to avoid them and how to deal with problems should they arise. Pool training is a very safe activity IF the safety rules are respected, but is about the equivalent of Russian roulette if they are not.

At the end of this article you should have a good idea of how to set up SAFE dynamic and static apnea practice sessions. The tables that are presented here are adaptations of the standard tables of the Apnea Academy of Umberto Pelizzari. There are other tables, and we have developed very different ones that we teach in our Advanced courses. However, my advice to the beginner or intermediate freediver is that the tables presentd here are superb tools for achieving 4:00 — 5:00 minute breath-holds and learning one’s body, its reactions and capabilities. This, in my opinion, is absolutely necessary before going on to ’empty lung’ work and more advanced techniques.

BREATH-HOLD is considered to have 2 distinct phases, the so-called, ‘Easy Phase'(EP) and the Struggle Phase’ (SP) . The Easy Phase is defined as being up to the first diaphragm contraction (DC) and the Struggle Phase as being from the first DC up to the Break of Apnea (BA).

In our first stage of development it is very important to observe these stages: when they occur, how long they last, how many contractions one can withstand, how severe they are, and how one reacts to each phase.

There are two important subjects that are NOT included in this article:

1)Ventilation ( before either a static or dynamic breath-hold) – From experience, ventilation must be taught personally and individually to be most effective, as it involves observation and correction of technique.

2)The Mental and Psychological Aspects of Static Apnea – There simply isn’t the space in this article to go into the many types of established methods that could be used to assist with this.

The Dangers!

The greatest danger is ‘Shallow Water Blackout’ (SWB). This is an ‘hypoxic incident’ that leads to a sudden loss of consciousness without any warning. When a diver’s mouth and nose are submerged (as when lying face down horizontally on the surface) and he suffers a sudden loss of consciousness in this position the result is usually a drowning if he is unsupervised. Although this is very easily avoidable, it is happening with increasing frequency and there have already been several reported incidents this year. When the O2 reserves fall below a ppO2 of about 0.1 ata there is a very high risk of an hypoxic incident.

Primary Hypoxia, or the so-called ‘samba’, is usually associated with convulsions, trembling and an unfocussed gaze. This is commonly referred to as ‘loss of motor control’.

Secondary Hypoxia, or SWB, is a sudden loss of consciousness.

‘Hypoxic incidents’ of varying intensity can be classified in stages from 1-3.

These stages do NOT always occur sequentially. A blackout, Stage 3, can occur without the symptoms of Stages 1 and 2 having occurred or having been observed. For example, a diver on low O2 reserves may not necessarily suffer the symptoms of a samba prior to a blackout, but may lose consciousness without any warning.

One of the dangers most touted ( particularly by ill-informed journalists )is brain damage due to prolonged breath-hold. They seem to confuse holding your breath for 4 minutes with the brain being anoxic for the same period. They are not at all the same thing! The body has remarkable adaptive mechanisms. In simple terms, the brain, which is the biggest consumer of O2, doesn’t like to suffer and imposes sanctions on the rest of the body long before it suffers damage. It shuts off consciousness so the consumption of O2 by the rest of the body is reduced. When we went to Oxford University as guinea pigs in experiments involving prolonged breath-hold of 5 minutes or so, it was interesting to watch the Central Cerebral Artery dilate in response to elevated levels of CO2 and reduced levels of O2, this in order to prolong oxygenation of the brain. (Refer to the EEG graph). Also, immediately after the onset of breath-hold there is a short period of tachycardia followed by a prolonged period of bradycardia until just before the BA, and upon the BA, tachycardia again : all adaptive breath-hold reflexes.

Altogether there seems to be NO case for apnea causing brain damage.

Essential Safety Rules Applicable to Static and Dynamic Apnea

1)Medical Exam Required

Each person participating in any apnea activity in a public pool (public or private session) MUST have taken and must produce a recent medical exam that would favour cardiac function, and any respiratory problems. It should look particularly at certain categories of arrhythmia. The doctor must also be instructed by a medical exam form ( one appropriate to the jurisdiction ) as to what particular areas the health risks and health conditions are considered contraindications for freediving. A note of all medications taken must to be made, and any instructor present must know of any long-term problem conditions such as asthma, epilepsy, diabetes, high/ low blood pressure  tendencies, etc. This will necessitate of a suitable medical form by an agency recognized in the jurisdiction, for example, in Britain the BFA. Also, anyone under the age of 18 should be required to present written permission from a parent or guardian.

2)Never Dive Alone

In any ‘wet’ practice, that is to say any time the mouth and nose are submerged, each person must have a partner who monitors and has bodily contact with him throughout the practice. This might mean holding his hand or ankles, if the partner is sitting on the edge of the pool. It is a reliable way to perceive the slight ‘trembling’ that often precedes a ‘samba’. This is different from the procedure in competitions and is for the purpose of a safer practice.

In dynamic, the safety diver swims alongside his partner, or joins him for the last phase of the apnea, rather than remaining at a distance, which could come to be interpreted as ‘on the edge of the pool and dry’. This, particularly with ’empty lung’ training (which will take place whether it has been advised or not), would minimise any delay in response time by the safety diver.

(i) Safety Partner: Signs to look out for in static apnea:

  1. Release of air
  2. Locking-up  (clenching with the hand)
  3. Letting go
  4. Trembling (felt in the hand)
  5. Sudden cessation of contractions in the ‘Struggle Phase’.
  6. Cyanosis detected on the surface between dives.
  7. Failure to return signals

(ii) Signs to look out for in dynamic apnea

  1. Erratic movement
  2. Loss of direction
  3. Sudden cessation of movement
  4. Release of air

Any of the above signs should result in the following actions:

  • TURN THE DIVER OVER AND/OR BRING HIM TO THE SURFACE IMMEDIATELY, WHILE SUPPORTING HIM
  • REMOVE MASK, GOGGLES OR NOSE-CLIPS AND BLOW ON HIS EYES. (The eyes have baro-receptors in them)
  • TALK QUIETLY AND ENCOURAGINGLY TO HIM. — DO NOT SLAP OR SHOUT AT HIM
  • IF CONSCIOUSNESS HAS NOT RETURNED WITHIN 30 SECS., START AR AND GET OUT OF THE POOL.
  • IF CONSCIOUSNESS HAS NOT RETURNED WITHIN ONE MINUTE, CALL FOR HELP, AND WITH PROFESSIONALLY QUALIFIED HELP GET READY TO PERFORM CPR AND ADMINISTER OXYGEN.
  • ALWAYS REMEMBER THAT WHAT FOLLOWS BLACKOUT IS DROWNING.

If there is doubt, REACT! Better risk the diver’s annoyance than that of his family.

Do not ask the lifeguard to keep an eye on you. If he missed the exact moment when you went down he won’t have a clue as to how long you have been holding your breath. Furthermore, his attention will always be divided if he is doing his job, and YOU are an added distraction.

3) Make a plan and agree on signals

A pre-arranged programme MUST be clear to the monitoring partner, complete with a program for the exchange of signals.

In the last phase of the end of a ‘declared’ extended breath-hold the exchange of signals will become more frequent. (Refer to AIDA competition rules).

Obviously, in doing tables (for instance Table A from the Apnea Academy) the only signal exchanged may be the signal to surface as the diver is only working to 50% of his maximum.

4) Never do static on the bottom

This entails putting weights on the diver, and in my opinion, it is unsafe. Furthermore, this technique complicates the exchange of signals.

One of the most lethally dangerous things to do is static at depth, either in open or confined water.

5) Static on ’empty lungs’ is NOT recommended

This is an extremely advanced practice which is NOT suitable for everyone, and when incorrectly performed there is a risk of pulmonary oedema. It should ONLY be done under the direct supervision of a competent and qualified instructor.

SWB happens very quickly and with no warning in empty lung practice. Also, it is sometimes hard for a partner to detect that there has been a blackout.

6) Do a MAXIMUM breath-hold infrequently

A warning MUST be issued against divers doing frequent breath-holds. Two maximum breath-hold attempts either in static, dynamic, or a combination of both in the same day SHOULD NOT BE ATTEMPTED.

This is an invitation to a near-certain SWB on the second attempt.

Frequent maximums on successive practices are mentally exhausting and unnecessary.

7) Do NOT continue a practice after a samba or blackout.

Disregarding this advice will lead to a second, more severe blackout.

If you observe cyanosis in your partner (purple lips) this is an indication that he has neared his limit and should not be pushed further. The level of effort should be maintained at this level, decreased or the practice session terminated.

8) No STATIC after DYNAMIC

  1. Dynamic is breath-hold with stress and a hard practice will leave you in no condition do an effective static table.
  2. However, a non-pushed static session before a dynamic session is acceptable.

9) Do NOT do 2 sets of tables on the same day.

This is likely to be too stressful as the blood, heart and nitric oxide levels require a recovery period.

10) Allow sufficient time for physiological development

When beginning a static regimen be aware that it takes the body time to adapt. There is a relationship between heartbeat and breathing, among other things. If this is pushed too hard at the beginning, particularly in ‘dry’ practice, there is a risk of incurring temporary arrhythmia.

11) Beware of Fatigue and Cold

Long before the onset of shivering, cold has the effect of reducing breath-hold time and the ability to concentrate. Fatigue is deceptive and one of its first victims is will power. Pushing a practice when fatigued can be counter-productive.

12) Beware of Dehydration

The types of ventilation most commonly practised by freedivers are very demanding on the body fluids. Exhaling expels large quantities of moisture. In a dry practice it is recommended to breathe through the nose. This moistens the air, filters it and brings it to body temperature thus protecting the delicate tissues of the larynx, bronchi, and alveoli etc. It also stimulates the production of NO (a vase-dilator).

13) Avoid use of a snorkel

There is only one dynamic exercise that requires the use of a snorkel and all the others can be done without. A snorkel should absolutely NOT be used in static.

14) Suiting Up

The use of a suit in static is essential for warmth, as warmth extends breath-hold capability and the floatation given to the legs affords better relaxation. In dynamic a suit is optional. One feels the movement of water along the body better in a bathing suit, however, a suit can be used for resistance training with the correct amount of weight to reduce buoyancy.

15) Eating

All breath-hold exercises and diving are best done on an empty stomach, at least four hours after eating. The digestive system requires a very large quantity of blood to digest and this reduces the quantity of blood that can be provided to the vital organs.

In Part II of this series, we will discuss the procedures for setting up the practice session and the application of both the static and dynamic tables.

Stephan Whelan
Stephan Whelanhttps://www.deeperblue.com
Stephan is the Founder of DeeperBlue.com. His passion for the underwater world started at 8 years-old with a try-dive in a hotel pool on holiday that soon formulated into a lifelong love affair with the oceans. In 1996 he set up DeeperBlue.com and helped grow the site to be one of the largest diving websites around today.

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