Training sessions in the world’s deepest pool

Long winter days are ideal for visiting thermal parks. We have quite a few of those in Slovenia, numerous of which are extremely popular. When I was a child, I often went to Atomske Toplice (today Terme Olimje) with my parents. I never forgot to take my swim fins, swimming mask and snorkel. I somehow smuggled them past the reception desk and the watchful eye of the lifeguards in order to spend most of my time underwater. But the experience wasn’t nearly as fascinating as the world under the surface of the sea, so I desperately wished for the bottom to be at least a metre deeper. “The pools just cannot be as deep as the sea!”, they said, while I was still dreaming about diving ten or twenty metres deep in warm thermal water. And, as many say, if you wish for something long enough, you just might get it. In 2014, Y-40, the deepest thermal pool in the world, opened its doors (and its pool with an incredible depth of 42 metres) in the Italian city of Padua.

 

 

 

I perform most of my basic preparatory sessions in 25-metre pools in Ljubljana. Their depth never exceeds 3 metres. The capacity of holding my breath while staying underwater as long as possible is a major component of my competitive performances. But it isn't enough. I must also find a way to adapt my body to the high ambient pressure at great depths. I usually perform these preparatory sessions at Lake Bled or make a quick jaunt to the Kvarner Gulf in Croatia. Only during the summer, of course, when the water heats up to an acceptable temperature of 15 degrees Celsius. This is why I was thrilled to hear that a pool with thermal, crystal-clear water of a temperature of 32 degrees Celsius and with an amazing depth of 42 metres has opened nearby.

 

 

The depth of Y-40 is more than enough to perform serious depth training. Why? Our goal is to develop a flexible thorax which gets deformed under high ambient pressure. If you swim too deep too fast, this can cause injuries. The critical point is the depth of 30 metres: at this depth, the ambient pressure is 4 bar, meaning that the thorax compresses by a factor of four! This deformation squeezes our lungs to the so-called residual volume. This is the last volume that our lungs can be compressed to without sustaining injuries. The reason for that is the fact that our respiratory tract and thorax are rather stiff organs. You must be wondering: how is it possible, then, that we can dive to a depth of over 100 metres? Regular training decreases the residual volume of our lungs while activating the diving reflex, which causes blood plasma to accumulate in the capillaries of the lungs. In this way, the incompressible “current” volume of the lungs also increases, which protects us from further deformations of our thorax.

 

 

The thermal pool in Padua has, therefore, become a real winter hub of freedivers from all over the world. It offers ideal, nearly laboratory conditions for training sessions intended to hone freediving skills. Due to the thermal water, there is no need to use neoprene clothes or additional weights. And that is what makes these dives so incredibly relaxed and fun!

 

 

The pool is extremely long and wide until it reaches the depth of 10 metres. At the depth of 15 metres, it gradually narrows into a seven-metre-wide tunnel falling to the depth of 42 metres. The tunnel itself is pleasantly lit and equipped with three deep ropes, enabling three freedivers to be in the tunnel at the same time.

 

 

A special attraction is the themed part of the pool, which is decorated with vintage cars, bikes, and even a replica of the lunar module one can find in the pool these days. All of it contributes to an even more pleasant training experience in the pool.

 

 

 

This year, you’ll be able to follow me in July during the big international competition “Vertical Blue” at the Bahamas, and in October when I’ll be attending the depth world championship in France. In the meantime, I’ll also go to Egypt for a preparatory period. I’ll notify you of each of these events in our Beehive as I go along. In May, I’ll also present some relaxation techniques that can be used to break depth records but are also extremely useful when it comes to coping with stressful situations. Therefore, you are warmly invited to continue reading the Beehive!