What happens when we breathe?

A cycle of life

Up in the sky the sun circles on its path from horizon to horizon, day by day, year by year. The sun is huge, 1,390,000 kilometers in diameter. You can fit 1,000,000 earths into the sun! And inside the sun a gigantic nuclear reaction is producing an unbelievable amount of heat and energy. A part of this energy radiates into the universe. High energetic particles and light. Eight minutes and 20 seconds after leaving the surface of the sun, after traveling 150 million kilometers through space, some of this energy arrives on our earth and gives you this warm feeling when it kisses your face on a sunny morning. But it also gives energy to virtually all live on earth, and the sun rays that stroked the skin of the dinosaurs 65 million years ago are now fueling your car or your commuter train when you go to work tomorrow morning.

Now what does this have to do with breathing? Well, the sun does not only warm your face, but it also kisses the leaves of millions and millions of plants in every corner of our little planet. And these green leaves use the energy from the sun to grow and prosper: they literally convert sunlight into energy that they can use to grow themselves and eventually also allows animals including you and me to grow. And this is how it works:

The air that surrounds you and me and also all those plants consists of 78 percent nitrogen, 21 percent oxygen, 1 percent of other gasses such as argon, a bit of vapor, and 0.04% carbon dioxide. Carbon dioxide or CO2 is mostly called out for its role in climate change and global warming, but actually it plays an important role for life on earth.

It consists of one atom of carbon and two atoms of oxygen, which are held together by strong forces that you can imagine as a rubber band.

Now the plants need carbon to grow their structures, their branches and trunks, their roots, their leaves, and also the sweet sugars that you devour when you get the first strawberries of the year or the sweet bananas in your fruit salad.

The only difficulty the plant faces is cutting the rubber band between the carbon and the two oxygens, and to do so, evolution has developed a process called photosynthesis. In all these billions and billions of leaves of all plants on planet earth, the same process happens: chlorophyll, the pigment that makes the leaves appear green, captures the sunlight, which contains the energy from the sun. This energy is strong enough to cut the rubber band between the carbon and the oxygen. Six parts of carbon dioxide together with twelve parts of water that the plant has sucked from the ground are converted into one part of glucose, better known as dextrose or simply sugar. The plant will use this to grow its structures. In the process also some of the water is left over, and most importantly, six parts of oxygen are released from their tie to the carbon. Remember that energy from the sun is needed to cut that tie. If at any time the carbon and the oxygen come together again, the same amount of energy will be released and available to work other cool stuff, as we will see in a small while.

Now, we let the plant grow for a while, storing up all that sugar while releasing oxygen into the atmosphere. After a little while, man comes and eats the plant, or maybe cow comes, eats the plant, and man eats cow. It doesn’t really matter whether a cow is involved or not, in the end man gets the glucose from the plant into his belly, either in its original form, or slightly modified. From there, after a while, the glucose ends up in our blood and our tissues and every cell in our body.

And now, finally, we will talk about breathing. Man breathes air, 78 percent nitrogen, 21 percent oxygen, 1 percent of other gasses such as argon, a bit of vapor, and 0.04% carbon dioxide. While the plants are mostly interested in the carbon dioxide, man is more interested in the oxygen. With every breath, 21 percent oxygen streams into our lungs. The lungs are like a tree. The trachea, the main airway, splits into two big branches, the bronchi. From there, smaller and smaller airways divert that eventually end in millions of tiny bubbles, the alveoli.

Andreas Heinemann at Zeppelinzentrum Karlsruhe, Germany

The alveoli are tightly interleaved with blood vessels. Here, the oxygen can get into the blood. But it doesn’t just jump from the air into the liquid blood, but it attaches to the red blood cells, the haemoglobin, in a process called gas exchange. Piggyback on the haemoglobin, the oxygen is pumped by our heart through our blood vessels. First through huge veins, like highways in the body. These highways branch again and again into smaller and smaller vessels, that allow to transport blood — and haemoglobin with the oxygen riding piggyback — to every single cell of our body. To the organs, to the muscles and to the brain.

If a cell signals that it needs oxygen, the hemoglobin releases the oxygen into the cell. Remember that in the cell some of the glucose that we have eaten earlier is already waiting. And now the human counterpart to photosynthesis is starting: almost all cells in the human body contain miniature power plants, the mitochondria. Mitochondria supposedly were independent organisms a few billion years ago, but decided to partner up with more complex cells somewhere in evolution, trading protection from the bigger cell for capability to produce energy. The mitochondria can take the glucose, and together with the oxygen they invert the photosynthesis. The glucose contains the carbon that the plants have stored there during photosynthesis. The mitochondria recombine that carbon with oxygen from the air to carbon dioxide. As a byproduct some water is produced (remember that photosynthesis consumed water) — so we are back to the original substances that were involved in photosynthesis. So what is the gain here?

Remember that we mentioned earlier that energy is released when the oxygen hooks up with that carbon again? This is where all the magic happens: the mitochondria capture that energy in a structure called adenosine triphosphate, or ATP. And ATP is the fuel of our bodies. It powers our heart, that beats 60 times per minute for as long as we live. It powers your muscles for every movement that you do. And it powers the cells of your brain that allow you to think, to act, and to be human.

To finalize the breathing cycle, let’s quickly see what happens to the carbon dioxide that the mitochondria synthesized: the cell releases it into the bloodstream — actually it jumps onto the same haemoglobin that delivered the oxygen to the cell. The carbon dioxide then rides piggyback through the blood vessels back to the lungs, where it transfers in the alveoli into the lung. With the next exhale it is released into the atmosphere, and will eventually be used by a big tree or a beautiful fern or a sweet strawberry plant to grow their fruits.

So literally, every single one of us breathes sunlight and is powered by sunlight. Summarized, the sun is a giant nuclear power plant, sends light and with it energy to the earth. Plants store that energy as glucose and convert carbon dioxide into oxygen in the process. Later, us humans eat that glucose and breathe that very oxygen, and convert it back to carbon dioxide and the energy that we need to live in the form of ATP. A cycle of life, and not unique to mankind, but we share it with all animals on earth.

And that is what happens when we breathe.

Oh, and the dinosaurs? The same things happened 65 million years ago, dense forests covered the land and captured the energy of the sun. Eventually, the forests died, got covered by layers and layers of sediments, and transformed into coal and oil over the eons. So in the end, the gasoline in your tank is just captured and conserved energy from the sun.

How I started to love the cold

My first encounter with the cold was in my first year at university. For some reason I decided to wear shorts — one complete year long. And in my home and study town of Dortmund, we have seasons, including a winter. Not too cold of a winter, but cold enough to make my daily 10k cycle to uni challenging. Still, all went well for about 10 months. Then, one day in December, the flu got me. I was more or less in bed for the better of 2 weeks, and I have been struggling with frequent colds ever since.

So what brought me back to the cold? What has driven me to even go on a five day expedition to Sweden to swim in ice water and hike for 2 hours through the snow covered wilderness south of Stockholm, with nothing but shoes, shorts and a woolen hat on me?

And even more, why did I feel reborn after these 5 days, instead of being in bed with a fever?

Actually, the experiences today and 15 years ago couldn’t be more different. Back then, I was driven by the weird desire to prove something, I don’t know whether to myself or to others. And my approach to enduring the cold was, fuck it, it is cold, I am shivering, I can’t feel my hands and legs, but yeah, I’m cool. Frozen to the bones? Fuck it, I am stronger than this cold and I’m gonna fight it. Well, that worked — until it did not. I did not listen to my body, I did not acknowledge that cold can be harmful, I did not listen to the signals that things might have been a bit too much.

And now? Swimming in a frozen lake is still fucking cold. But the Wim Hof Method has prepared me to embrace the cold instead of fighting it. Relax instead of clenching my teeth. And most importantly, to listen to my body and start the cold exposure gradually and safely, and increase it in small doses to let the body adjust.

But still, what fired up the idea in me to go to Sweden in first place, me, that guy who always has a cold and catches the flu if a dog three blocks away does a sneeze?

Since my first cold experiment 15 years ago, I had a few more, most times friendly encounters with the cold. Most notably probably a dip in the Baltic Sea in March, some 7 years ago. I was in visiting the adorable, life-loving Lena, who I had met and hosted a few days earlier during her CouchSurfing adventure to Paris. The weather was cold, but sunny, and since Rostock has beautiful beaches, what else would you do on a clear day than catching some sun at the sea?

After a while dark, rain-swollen clouds started appear on the western horizon and slowly drifted our way. In a now-or-never moment we skinny dipped into the ice-cold Baltic Sea. My body reacted to the extreme experience by emitting all endorphins known to men, creating a deep happiness. The sun still sent its rays through the clouds when thick drops of rain started falling, and a rainbow arched above our heads while we danced the warmth back into our bodies.

Fast forward to Amsterdam, 2016. I had just moved to a new town and started a new job, when a friend of our boss offered an “Iceman Workshop”. Who the heck would spend half a day to prepare for a cold bath, I thought, I can do that by myself without wasting my time! I couldn’t have been more wrong, but that I only learned 2 years later, after skinny dipping once more into natural water on my through hike in the Italian Alps. This time, for some reason, the bathing experience turned into a habit of cold showers (very easy to maintain on mountain retreats who’s limited hot water reserves frequently turn your morning shower into a cold experience).

Back home I remembered that weird Wim Hof iceman workshop thingy. I did my research and started to work with the online material. And finally in early 2018 I visited my first Wim Hof Workshop by the awesome Daniel Kluken. While I had built up a solid relation with cold water in the past years (I don’t kill you, you don’t kill me), the workshop again changed my perception completely. I was hooked. 2 months later I found myself swimming in ice-covered water and hiking half-naked through the Swedish wilderness. I signed up for the instructor academy.

And I realized that only a small part of the Wim Hof Method is actually about cold experience — but I leave that for another post.