[Article updated on 19/09/2023]
According to ConsoGlobe, every day, nearly 15,000 liters of air pass through our airways and lungs, a figure that demonstrates the vital importance of breathing. For its part, metabolism is inevitably dependent on the respiratory system, the latter being responsible for the supply of oxygen which we need to transform nutrients into energy, and to eliminate certain metabolic waste. But what is the real importance of respiration and oxygen on metabolism?
Before reading on
I’m not an expert in this field, but I am passionate about nutrition and health.
The articles you’ll find on my site are the result of in-depth research that I’d like to share with you. However, I would like to stress that I am not a health professional and that my advice should in no way replace that of a qualified physician. I’m here to guide you, but it’s important that you consult a professional for specific questions or medical concerns. Your well-being is important. So be sure to consult the appropriate experts and take the best possible care of yourself.
The role of oxygen in the body
If the metabolism is defined as “the action of assimilating food and converting it into energy”, it turns out that it needs oxygen to function sustainably. The body itself will deteriorate quickly without an adequate supply. Improving this oxygen supply, as well as the absorption and assimilation process, is therefore essential to optimize the quantity of energy synthesized and eliminate metabolic waste.
In truth, even the most basic act of daily life, such as moving, consumes oxygen, as you can read on this site. To digest and assimilate food, we need oxygen. Probably all body functions use oxygen, but only to different degrees. It also turns out that we need oxygen to burn most nutrient molecules. However, in theory it is possible to burn sugar to produce very small energy molecules without using oxygen. We call this exception “anaerobic metabolism,” and it’s what cells do when we exert considerable physical effort.
There are therefore two types of cellular respiration (which we can now call “cellular metabolism”): aerobic respiration and anaerobic respiration. Aerobic respiration occurs when there is enough oxygen to fuel the body, while anaerobic respiration occurs when there is no oxygen. We therefore determine the type of breathing that occurs depending on the type of physical activity we provide, and depending on its intensity and duration.
Breathing takes place in the lungs
Breathing is simply the process of transporting oxygen from the air to body tissues and, at the same time, eliminating carbon dioxide. For its part, metabolism refers to all chemical reactions that take place in the body, including reactions that use oxygen and generate carbon dioxide. Oxygen and carbon dioxide are therefore involved in both respiration and metabolism.
Air enters the nose, where it is warmed and humidified before entering the lungs. Once the air reaches the alveoli (small air reservoirs in the lungs), the oxygen is distributed in the blood, through the capillaries of the alveoli, while the carbon dioxide (product of metabolism) leaves the blood to then diffuse into the air. It is therefore during exhalation (an essential phase of breathing) that most of the carbon dioxide is released into the atmosphere.
Metabolism occurs in all tissues
After leaving the lungs, oxygenated blood is pumped throughout the body by the heart. Once it enters the tissue capillaries, the oxygen is released from the blood and enters the cells, where it will be used in metabolic reactions. These then produce carbon dioxide which, once again, enters the blood as it leaves the tissues, to be returned to the lungs and eventually into the atmosphere.
In fact, all chemical reactions that occur in the body are necessarily metabolic reactions. Some reactions use molecules to produce energy, while others, conversely, create molecules using energy. The first type of reactions, which uses energy, includes the creation of new membranes and the synthesis of proteins. Each cell thus created must store energy recovered from nutrients so that there are enough resources to create new molecules.
The phases of cellular respiration
There are three essential steps that determine cellular respiration and cellular metabolism: glycolysis, oxidative phosphorylation and the Krebs-Martius cycle.
Glycolysis is the metabolic process that occurs in the cytosol of cells, resulting in the conversion of glucose (sugar) into two pyruvate molecules. It is an anaerobic reaction which, as a reminder, does not require oxygen. This results in the production of two molecules of ATP (adenosine triphosphate) which constitute usable energy.
Then comes the glycolysis stage which uses the pyruvate molecules produced. In the presence of oxygen in cell bodies, pyruvate can be dehydrogenated and decarboxylated to form an energy-rich molecule. This results in the release of carbon dioxide into the atmosphere, which therefore involves the loss of oxygen atoms combined with oxide (therefore unusable for cellular respiration).
THE Krebs–Martius cycle is an aerobic phase that requires oxygen, and occurs in the mitochondria of every cell in the human body. Mitochondria are sort of the powerhouse of the cell, producing most of the cell’s supply of ATP. In these intracellular areas the electron transport chain also occurs, which results in the transfer of electrons to oxygen receptors.
When every cell in the body gets everything it needs, the result is the accumulation of a large amount of energy as well as optimal cellular respiration, which leads to better metabolism. This is therefore the capital importance of breathing, especially since when the metabolism is functioning normally, its energy needs will be satisfied. This results in better tissue repair, rapid detoxification, better functioning of hormones…