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From tec diver to freediver - part 2

Discussions on diving

Where Chloe talks about all things diving, from freediving, scuba diving, technical and cave diving and diving courses. And also a lot about diving on Tablas Island, Philippines, a brand new and unexplored diving destination.


From tec diver to freediver - part 2

Chloe Wessling

Freediving training - Day 1 continued

The next exercise Jan had me do was hold my breath; sounds easy enough, right? Not so much in practical application though when the whole point is to push the limits of how long you can hold your breath. This was an uncomfortable experience for me and I was introduced to a free diver’s relationship with carbon dioxide (CO2). This is probably the one greatest difference between free diving and scuba diving.

CO2 is the driving force in our body’s breathing cycle: when a certain amount of CO2 builds up our body realises that it needs to take a breath (and importantly exhale said built up CO2) and we do this for the most part without conscious thought. This happens independently of the level of O2 but does generally happen long before the level of O2 drops to the point that it can no longer sustain your body.

In open circuit scuba diving you want to avoid a build-up of CO2; it makes you feel like you are not able to get enough breath and this can cause a lot of anxiety, particularly in new divers. And this is where the abdominal breathing is important when scuba diving so that you are exhaling adequately to expel the built up CO2 and prevent this situation. In circumstances where you are working harder than usual underwater (perhaps fighting a strong current) your CO2 levels will rise accordingly and you want to really concentrate on the forceful, complete exhalations to compensate for the increased CO2 your body is producing.

In closed circuit rebreather diving CO2 is one of the biggest enemies (a close third behind low PPO2 and hyperoxia). The CO2 scrubber (that removes the CO2 from the gas you are breathing) is one of the most important components of a rebreather and a lot of time is spent in making sure that the absorbent is packed and assembled correctly and in ensuring that the lifespan of the absorbent is not exceeded is an important consideration in planning your dive or series of dives. For the most part a scrubber malfunction will be caused by user error so you have to pay special attention to it when you are preparing your rebreather for a dive

If CO2 levels rise too much when you are diving on a rebreather the signs and symptoms can start very subtly and it can become a very dangerous situation very quickly if it is not recognised and dealt with appropriately in the early stages. High CO2 levels can, in fact, cause you to pass out, which when you are diving usually results in drowning.

One of my most vivid memories from my rebreather courses was the ‘CO2 hit’ that my instructor put me through so that I knew what high CO2 levels felt like. It was the end of a day of diving and we were back at the dive shop. Before we broke down the rebreather for cleaning my instructor removed the scrubber and put me on the breathing loop.

He put the PPO2 up pretty high, something over 0.5, so hypoxia was not going to be an issue and I sat there breathing on the loop, the CO2 levels building with every breath. Maybe for the first minute or so nothing much seemed to happen but slowly the symptoms of CO2 started to appear and quickly started to worsen.

My breathing rate started to increase, not much at first, but I was sitting down at complete rest and my breathing rate should have remained the same. In not much time at all I was breathing very heavily, a rate similar to the rate I would breath if I were to go for a jog, while I was just sitting there doing nothing. There is no way I could control or slow down my breathing, there was such a build-up of CO2 that my body was desperately trying to expel so my breathing continued to get heavier.

My abdominal muscles started twitching from the CO2 build up and my brain started to struggle to think. It got to the point where the only reason I actually bailed out was because of the trust that I had in my instructor so that it was more of an instinct to follow his direction when he told me to bail. Breathing fresh air again, with the opportunity to finally expel the build-up of CO2 it took me a good couple of minutes to bring my breathing back to normal and to be able to think straight again.

Petr experiencing a CO2 hit on my rebreather

This is a fantastic experience to have as a rebreather diver because you learn to recognise a CO2 build up before it’s too late; this could save your life if it happens on a dive. What it also does is to condition you to not accept high CO2 levels and instinctively act to reduce the CO2 when it does build up. Which is exactly the opposite of what freedivers do…

It is the very nature of free diving that the CO2 levels during a free dive will build up and the key is to be able to remain calm and in control when that does happen, so that you can make it back to the surface to breathe again. Free divers train to increase their tolerance of CO2 and calmly accept the physical discomfort associated with high CO2 as this is what usually limits their dive time rather than a lack of O2.

So, back with Jan lying next to the pool I held my breath. The first time was embarrassingly short and I took a breath as soon as it became slightly uncomfortable. As I held my breath again and again, with Jan’s calming voice helping me to stay relaxed and focused as my diaphragm would start to contract from the CO2 build up, I managed to extend my breath hold time a short while, something around 2 minutes, and I became… not more comfortable with the CO2 build up, but more accepting of the effects; I knew that in this context it was not, in-itself, a life threatening condition.

Pool session

Next we went to the pool to practice static apnea (ie. put your face in the water and hold your breath). The trick here was to completely relax your body and just float in the water near the edge of the pool. I started with a snorkel in my mouth, face down in the pool and tried to relax every muscle in my body and slow my breathing rate, utilising the relaxation and breathing techniques we had just practised, in preparation for the breath hold.

This simple act was much harder than expected for me to accomplish. As much as I love diving and being in the water and as relaxed as I feel in the water when I am diving there is still always some level of tension and alertness. Just being in correct trim while scuba diving means that certain muscles are tensed, even if you are not finning, and alertness and readiness to act are essential to have at all times for the unlikely event of an emergency situation. So trying to let go of that tension and alertness became my main struggle with the static apnea.

This complete relaxation in the water is possibly not so relevant to scuba diving, at least for me personally, as I feel it is important to in control and alert in the water but for people learning how to scuba dive it may be helpful to alleviate some of their anxiety of being in the water. Not that I would suggest that new divers attempt breath holding, as that goes against the golden rule in scuba to never hold your breath, but a lot of people have a fear of being in the water so in-water relaxation techniques could be helpful.

After a number of attempts at the static apnea I did manage to succeed to an acceptable level. It was a bit frustrating for me actually. I’m generally a pretty quick learner and once I know the theory of something I can usually do it without much trouble. But these skills certainly took some practice for me to get the hang of it. But each attempt was better than the one before though and it wasn’t long before we could move on to the open water portion of the course.

Open Water Session 1

This is where I put everything Jan and I had just done together to accomplish freedives. We swam out off the beach in Binucot Bay with just our wetsuits, fins and mask (I felt a bit under-dressed getting in the water like this). We had a buoy with a weighted line attached to the bottom of it and Jan lowered the weight to 10m deep so I just had to follow the line down and then back up again on each dive.

On my first dives I used the free immersion technique, which involves pulling yourself down the line, head first, using just your arms. This is one of the easier methods of freediving as you are using your smaller arm muscles, rather than the large muscles in your legs if you were to use your fins and kick your way down, and so your body requires less O2 and creates less CO2 during the dive.

The preparation for each freedive is called the breath-up. Just as we practised in the pool I floated face down on the surface with the snorkel in my mouth and concentrated on slowing my breathing rate. Utilising the abdominal breathing I counted my breaths until I got to a slow 5 on the inhale and 10 on the exhale and could notice my heart rate slowing.

After one full inhalation I went down the line, hand over hand, equalising throughout, and felt pretty good about it until my brain kicked in and I realised that while all might be good right now I still had to make it back to the surface before I could breathe again; that made me wary of going too far down the line. Like I said at the start, I like breathing, so it was a bit scary at first to realise just how much water lay between me and my next breath of air.

With repeated practice however I started to be able to gauge how comfortably I would be able to make it back to the surface. The first time I got contractions from the CO2 build up occurred while I was on an ascent and was an interesting moment. My tec diving training kicked in though and I maintained my relaxed state, stayed calm and just focused on what I had to do to get to the surface for that next breath.

In a sense free diving is much like tec diving or cave diving; you have to stay calm, relaxed and in control at all times. The moment you panic is the moment you will most likely die (or at least you will likely die very shortly after you start to panic). Granted, in free diving you generally have a smaller time frame and more limited options if a problem occurs (entanglement with the line for example) but remaining calm and in control is the key to surviving the experience.

Jans’ instruction throughout the day was impeccable and he managed to get me looking like a free diver by the end of the session. As a scuba diver I am used to being horizontal in the water, head up, back slightly arched, legs bent at the knees. However, in free diving you want to be a straight line from your head to your feet as this make you as streamlined as possible and minimises the water resistance against your body. Less resistance equals less effort to move through the water which equals less O2 used and less CO2 generated, the aim of any freediver. Keeping my head straight, chin tucked in and not looking in the direction I was travelling was probably the hardest habit to break but it does make keeping the rest of my body in a straight line much easier.

I was kind of surprised at how quickly I became comfortable going deeper and deeper on a single breath. I made it to 10m without too much trouble and by the end of that first session I had reached around 15m, far beyond what I thought I would be able to achieve prior to staring the course and this was just the first open water session.

To be honest I can’t say I was completely comfortable as I reached each new depth but I did have the skills and knowledge to be able to do it, which was pretty cool. My quick progress was in some way related to my experience with scuba diving; I am comfortable in the water and have good water skills and I know how and when to equalise. Importantly I don’t have any great fear of being in the ocean or in deep water so it was easy for me to stay relaxed throughout the freedives.

Freediving training - day 2

Open Water Session 2

On the second day I was starting to get in to the rhythm of freediving. My breath-ups were getting faster as I was able to slow my breathing rate quicker. I had a better idea as to what to expect on each dive and I was getting used to the effects of the higher CO2 levels that occurred towards the end of each dive. The important thing for me was to remember that even though the high CO2 levels were causing contractions of my diaphragm I knew that I had sufficient O2 left to comfortably make it to the surface. At the shallow depths and short times that I was diving hypoxia was not an issue; the high CO2 was merely uncomfortable, but not life threatening.

So, on this second day of free diving I reached 20m on one breath and I was quite surprised that I actually managed to do it. It may have not been the most elegant dive and I certainly felt that I could have been more relaxed throughout the dive but I had proved that I could do it. The rest was just a matter of continuing to practice.

This new found knowledge and skills and comfort in the water could quite possibly help in an emergency situation while scuba diving, although I honestly hope I never have to test that theory. To know that I can comfortably swim for 45 to 60 seconds on one breath is somewhat comforting. Although in reality, to do that in full tec diving set up, as opposed to the streamlined freediving gear, would mean the distance I could cover in that time would be greatly reduced. However being comfortable with, and not panicking when faced with CO2 contractions, could help in the worst case scuba scenario.

The other skills that we practised on day 2 were rescue skills. This involved rescuing an ‘unconscious’ diver from around 10m deep, bringing them to the surface and giving rescue breaths. This is another useful skill to have for anyone that spends time in or around the water. 10m is quite a distance to come when you are pulling another body along with you and was not the easiest to accomplish. Once again I hope this is one of the skills that I never have to use in real life but it is good to know what I am capable of if it ever does happen.

We did a third open water session after this, along with Wil and Petr, and this is where I became more comfortable being under the water on just one breath. Like any other skill continued practice is essential if you want to improve. Also being in the water with other freedivers and watching how they dive was a great experience too. They were both obviously more experienced with freediving than I am and I learnt a lot just from being able to watch them dive.


So after all this I was now a freediver and I found it to be a very interesting and valuable experience all round. Although I have not been converted entirely to a freediver (I could never give up tec diving, it is the love of my life) I have still gained a lot from completing the freediving course. I have found an even greater level of comfort in the water (something I didn’t even think was possible considering I already felt most at home when submerged) and gained valuable skills and experience that will make me a better diver.

And more than that I had the opportunity to meet and get to know the often overlooked (at least in scuba circles) part of the diving community that is freedivers. While there are a great many differences between scuba and freediving, whatever method you choose to utilise go in to the deep blue I think that all divers are motivated by similar reasons; a love of the water, the joy of exploring parts of this planet that the vast majority of people never see, and the peace that you can find both with-in and with-out when you are under the water. 

Post script - freedivers to scuba divers

After I had completed the freediving course with Jan I returned the favour and took all 3 guys out for a scuba dive. Wil has his open water scuba certification and had completed a handful of dives previously. Jan had done a few try-dives on scuba, but never done the course and for Petr it was his first time on scuba. 

With such inexperienced scuba divers I was a bit apprehensive as to how well they would manage during the dive but I was pleasantly surprised to see how comfortable they were underwater and how much natural skill they had in maintaining good trim and buoyancy. Even Petr, who had never been on scuba before, looked like he had been diving for years and was an absolute natural at it. 

Surely this is related to their experience with freediving; they were already comfortable  and used to being relaxed underwater and understood the physics of diving. and I would be interested to hear from other freedivers who have learned to scuba dive and what their thoughts on the experience are.