Don’t Remove Your Spleen
In this article we discuss the spleen and why it’s a hot topic of conversation in the freediving world. We also highlight some epic underwater people that have provided science a framework to ask some pretty insane questions about the mammalian dive reflex, and our bodies capabilities in the water.
So let’s tuck into it.
The Spleen
First off, what is the spleen? Located in the upper left part of your abdomen (under your rib cage if you’re feeling for it), the spleen has, in some ways, raised more questions about its function than has delivered answers.
It is not uncommon to find literature stating that the spleen plays a small role in maintaining human existence, unlike its more important organ buddies, such as the heart, liver, or lungs. Research does show that it acts as a filter for blood, destroying old red blood cells, as well as providing extra immunity for certain bacteria. As a secondary function, the spleen acts as a reservoir for stored hemoglobin and oxygen cells.
Anyone who has a splenectomy can live normally but is encouraged to be vaccinated against bacteria, namely Streptococcus pneumonia, Neisseria meningitides, and Haemophilus influenza. You can guess what these bacteria normally lead to.
It has also been shown that up to 30% of people have an extra spleen, which in most cases is quite small. However, if needed, this “accessory spleen” can grow in size and take part in a removed primary.
So, how does any of this relate to freediving?
Freediving & the Spleen
In eastern Indonesia, there remains a small community of Bajau people, known by many worldwide as “Sea Nomads.” The lineage of this tribe originates from the Philippines but has since expanded to occupy the shores of Indonesia, Malaysia, and other South-East Asian countries.
Rough estimates indicate there are roughly 1 million Bajau people spread across the warm oceans. Traditionally, Bajau people spent 8 hours a day (or more) diving to varying depths for food. They effectively spent 60% of their time in the water.
Bajau people were shown to have an average of a 50% larger spleen size than their land-based, farming counterparts, the Saluan.
With a 50% larger spleen, it means the Bajau people have more stored haemoglobin in their body, lending evidence to the fact that their mini, internal “scuba tank” could be of assistance when diving.
This theory is further supported by a study of the Japanese Ama divers, which demonstrated a splenic contraction of 20% (at 20-30m) correlated with a 10% increase in haemoglobin concentration.
You heard that right; the pressure of the water is contracting the spleen and putting more haemoglobin into the bloodstream.
Remember Mr. Sperm Whale from last week? Well, it turns out something similar is going on when he dives deep. This makes that tragically low heartbeat (or 2bpm) make a LOT more sense. As a side note, various species of whales have been shown to have as many as 13 accessory spleens upon dissection. So there’s that.
The takeaway from all of this is that the spleen is relevant, and freedivers should avoid having it removed. Studies show that elite athletes (both freedivers and high-altitude athletes included) have both higher splenic volume as well as a higher magnitude of splenic contractions. Yes, this means it’s a trained response.
The next question is obvious. Are we evolving into whales?
Sure. It’s going to take us quite a while to catch up, and we have some flukes to grow and some legs to lose, but we might get there.
More importantly, we can continue to understand that the meat suit we walk around in during the day is much more than a land-walker. It also has vestigial functions that may be left over from whence we were all submerged. We really are marine mammals.
If your heart rate is half as high as ours is after this brief lesson in biological evolution, you will certainly need this daily exercise to calm you down.
Daily Exercise for Freedivers
This week we go old school and try out an age-old technique that has modern applications to freediving. In fact, we don’t claim to have invented any of these techniques. That would be ridiculous.
We call it “sound layer cake.” It was probably not called that before.
Sit with a straight back, chin slightly down, ears slightly back, and the crown of your head reaching up towards the sky.
Don’t worry about doing this in a noisy environment. Doing this outside can actually heighten the experience.
Find your breath slowly, feeling the coolness of the air as it goes into your nostrils and the warmth as it goes out.
Take 5-10 breaths here, closing your eyes to ground in.
Keeping your eyes closed (after you’ve read this through), focus all of your attention on the sounds furthest away from you. Maybe some cars or waves in the distance, or a loud construction site a scarily far distance away.
Move in a small distance in your awareness, discerning sounds that are not a bit closer to you.
Finally, move forward into your immediate surroundings. The fan next to your bed, the sounds of your body shuffling to find a comfortable position.
Freely move in and out of each of these layers as you deem necessary, but be sure to immerse yourself fully in each one. Allow the sounds to amplify with focus.
This exercise teaches us how little we activate our senses and how our “narrow focus” provides us with a limited perspective. The more we practice the sound layer cake, the more aware we become of the thousands of sounds that are around us all the time, yet our brain chooses to ignore them.
Fluid Focus is a community of water explorers who use the ocean as a means of connecting back with themselves. Whether you are a freediver, surfer, or part-time ocean lover, we share a passion for the ocean. Fluid Focus Retreats are all immersive ocean therapy retreats that incorporate freediving, yoga, meditation, and mindset practices to help people connect with the ocean, connect with themselves, and connect with others.
References:
Holmström, Pontus K., et al. "Enhanced splenic volume and contraction in elite endurance athletes." Journal of Applied Physiology 131.2 (2021): 474-486.
Ilardo, Melissa A., et al. "Physiological and genetic adaptations to diving in sea nomads." Cell 173.3 (2018): 569-580.
Hurford, WILLIAM E., et al. "Splenic contraction during breath-hold diving in the Korean ama." Journal of Applied Physiology 69.3 (1990): 932-936.
e Silva, F.M.O., Carvalho, V.L., Guimarães, J.P. et al. Accessory spleen in cetaceans and its relevance as a secondary lymphoid organ. Zoomorphology 133, 343–350 (2014).