Exploring the deepth : our freediving adventure
- chloe67523
- Nov 3
- 8 min read
At Abyss, the marine world holds (almost) no secrets for us. But this time, we wanted to step outside our comfort zone a little to explore a subject that is still related to the sea, but one that we are less familiar with: freediving.
You may have seen it mentioned: we are supporting Charlie, our PhD student in R&D, in his freediving activities, particularly during the ‘Cormorant Free Diving Week’ event.
Read on to find out more!👇
The Cormorant Free Diving is a freediving centre located in Ajaccio, Corsica (France), developed in 2021 by Abdel Allouach and Chantal Marzin, two renowned figures in the world of freediving. The centre welcomes enthusiasts, amateurs and professionals who want to immerse themselves in the discipline of freediving in a natural environment. Today, we are delighted to introduce you to this fascinating world and share with you Charlie's experience of practical training, theory lessons and competition.
What is freediving?
Freediving sports refer to a set of activities performed during a voluntary cessation of breathing, i.e., when the renewal of the air around us within our bodies is stopped.
Most often, freedivers practise in an aquatic environment, which is naturally conducive to this cessation of breathing.
Note: The word ‘breathing’ is often misused when referring to this sport, as the process of gas exchange in our lungs at the level of the pulmonary alveoli does indeed continue when practising freediving.
Different types of freediving
Freediving can be broken down into different practices, depending on the equipment used and the setting in which it is practised.
We can therefore distinguish between:
"Indoor" freediving, where the aim is to achieve the best performance in terms of time (static apnea) or distance (dynamic apnea) in a swimming pool. For dynamic freediving, several sub-disciplines can be defined depending on the equipment used: fins (DYNB: dynamic bi-fins), monofin (DYN: dynamic) or no fins (DNF: dynamic no fins).
"Outdoor" freediving, which most often involves diving to great depths in natural environments. Here again, several sub-disciplines are described according to the equipment used for diving. In addition to the sub-disciplines of indoor freediving, outdoor freediving includes the concepts of constant weight or variable weight, free immersion (FIM), where the freediver moves solely by pulling themselves along a cable, and ‘no limit’, where a device called a ‘ballast’ is used to take the diver down to depth and bring them back up. This is the practice depicted in Luc Besson's famous film ‘The Big Blue’.
What is happening in the body during a freediving?
The air around us, composed of approximately 79% nitrogen (N2) and 21% oxygen (O2), provides our bodies with the vital support they need to function. When we breathe, oxygen is consumed and carbon dioxide (CO2) is produced as waste, which is then expelled.
When ventilation is deliberately interrupted, these gas exchanges continue, which inevitably has two consequences in our bodies:
A decrease in O2 levels since it is consumed and not renewed.
An increase in CO2 levels, as it is not eliminated.
Although a lack of oxygen is mistakenly perceived as the main reason for ending an apnea, it is actually the high carbon dioxide levels and intolerance to them that give the freediver an irresistible urge to breathe.
Although the human body may not appear particularly well suited to aquatic environments at first glance, it is nonetheless a mammal that has inherited remarkable adaptive abilities to survive in situations conducive to apnea:
During immersion (more specifically, when the face meets cold water), the heart slows down (bradycardia) and blood concentrates more towards the essential organs to oxygenate them (peripheral vasoconstriction). This phenomenon is called the diving reflex.
In outdoor freediving, when the pressure is such that the lungs reach their residual volume (the volume at which they become incompressible), blood concentrates in the tissues to counterbalance this pressure and prevent the lungs from ‘imploding’. This phenomenon is called blood shift.
What about risks?
Like any sport, freediving is not without risks. However, while these risks may seem significant and daunting, practising freediving in a supervised and disciplined manner can considerably minimise them.
The main risks involved in freediving are as follows:
A little feeback on Charlie's week
Charlie tells us: ‘My goal for this week was to practise, improve and learn new techniques and tips as part of my ongoing efforts to enhance my performance. I went there with a spirit of discovery and improvement, knowing that I would be supported by highly skilled and effective coaches and a well-established organisation.’
A typical day at Cormorant Free Diving
The week consisted of five days of training and two days of competition organised by AIDA (International Association for the Development of Apnea).
The first day was mainly devoted to briefing participants about the week and the club's rules to ensure that everything ran smoothly.
A day in Ajaccio begins at 8:30 a.m., when we set off in a semi-rigid boat to reach the club's performance platform, located in the middle of Ajaccio Bay at a depth of 180 to 190 metres. 🌊
After a warm-up, the diving session begins at 9 a.m. and continues until 11 a.m. Everyone can then dive to the depth of their choice, or even try the performance cable, a device that replicates the conditions of a real competition. 🏆
However, participating in a performance cable session involves a specific protocol: you must register your participation the day before, indicating your performance, note your order of appearance, warm up on the day, then perform 💪 before concluding with the safety protocol on the surface — just like in an official championship.
Throughout the session, participants are accompanied and supervised by experienced coaches, who ensure their safety and are always on hand to offer advice.
Once the practical session is over, it's time for the theory lessons! 📚
Improve oneself on dry land
And yes, Cormorant Free Diving Week is not limited to practising in a natural environment; it also includes theoretical conferences to give freedivers all the tips and tricks they need to improve their technique and performance.
As you can imagine, there was no afternoon rest, as the week also featured three lessons.
The first theory class 🧑🏫focused on the basics of freediving: here, we reviewed the fundamentals of freediving in depth 🤿, including different breathing techniques, immersion, finning, equalisation (ear clearing), turning at the bottom of the performance cable and ascending. So many tools and areas for improvement for future training sessions.
The second theory lesson 🧑🏫focused on equalisation: although not the only factor, equalisation is crucial in freediving. The aim of the lesson was therefore to explain the physiology of what happens during equalisation.
In concrete terms, equalisation allows the pressure between the outside and inside of the body to be balanced, particularly in the ears 👂 and sinuses. As you descend, the water pressure increases and, in addition to this, there is a vacuum in the inner ear which ‘sucks’ the eardrum, which can become painful. To avoid this, freedivers must send air from their lungs to their ears using various techniques such as the Valsalva manoeuvre (pinching the nose and pushing air from the lungs) or the Frenzel manoeuvre (pushing air trapped in the oral cavity).
Equalisation is quite a difficult aspect of freediving, because the deeper you dive, the harder it is to move enough air to balance your eardrums. The course also covered other crucial aspects such as why you need to equalise, what prevents equalisation, etc.
Here's a little tip just for you: one of the main obstacles to equalisation is... stress (well, well, well, it's been a while) and what it entails: difficulty relaxing, tension, etc.
Finally, the third and final theoretical course 🧑🏫 focused on the importance of the mind in freediving: here, the four pillars of the mind were discussed, as well as the importance of the mind and what could hinder it in freediving, and relaxation techniques 🧘 such as cardiac coherence. These were precise and particularly interesting lectures, with the icing on the cake being information that has been clinically proven by science.
Charlie's performances
Each day of diving, Charlie set himself the following goals:
Day 1: PB (Personal Best) announced at 26 metres -> goal achieved ✅
Day 2: PB (Personal Best) announced at 30 metres -> goal achieved ✅
Day 3: Charlie moves on to the performance cable with a performance announced at 25 metres -> goal achieved ✅. He then achieves a second performance at 33 metres on a training buoy.
Here, Charlie explains that he deliberately set a lower performance target so that he could focus on his technique and get in shape for the competition.
Day 4: 30 metres announced -> goal achieved ✅ + a short photo shoot as a reward. 📸
Day 5: Charlie moves on to the performance cable with a PB (Personal Best) announced at 35 metres -> goal achieved. ✅
One of the rules in freediving is that in competition, you cannot announce a PB of more than 5 metres above your current PB. Here, the goal was to reach a PB of 35 metres in order to be able to announce 40 metres in competition. The aim was also to perfect the work done at the beginning of the week. This session was ‘incredible’ for Charlie, with lots of great sensations and a boost of confidence for the competition. 😍
He then followed up with some free immersion work (cable traction) and dynamic breaststroke without fins.
After this last training session, it was back to base for a competition briefing (procedure, safety rules, etc.).
The competition
It's the big day, and the dolphins had better watch out! 🐬
🎙️Who better than Charlie himself to tell us about the competition:
"For the competition, I had announced a PB of 40 metres, which was a first attempt for me. I was a little stressed, but well prepared. The day before and the morning of, I trained on dry land to visualise the dive. Lying in my bed, stopwatch in hand, I would hold my breath and imagine myself underwater, compensating and applying the same movements and protocol as during a dive.
On the day, I arrived and, to warm up, I did two descents (with a 6-7 minute break between each descent), doing a 30-second static stop at a depth of about 20 metres while imagining going down to 40 metres. I came back up and practised the safety protocol to get the right reflexes.
Then comes the mental work: I put myself in my bubble and anchor myself in the present moment. The judges give the starting signal, and I have only 30 seconds to go. ⏱️
Here we go, diving in with my fins, I reach 15-20 metres and start to sink due to the pressure (which is normal). Equalising becomes difficult at around 36 metres, I almost turn back, but I relax, equalise and it works. I reach 40 metres, grab the white tag (mandatory to validate the performance), then start to ascend.
I spot the safety freediver at 20 metres, then at 15 metres, then I come up, follow the safety protocol and the judge gives me a white card: the performance is validated!" 🤩
The ending word by Charlie
"It was an incredible experience 😍, and it made me want to practise even more. It's almost addictive, because when I did the performance, I couldn't help thinking that I was capable of doing more. I wanted to see how far I could go. But everything in its own time. In freediving, even if you're quite comfortable with it, it's important not to progress too quickly so that your body has time to adapt, otherwise there are risks to your lungs, eardrums and other parts of your body."
