Is oxygen secretly a poison?

Molecular oxygen (O₂) is a colorless and odorless gas, and makes up about 20% of the atmosphere, which is inhaled daily by billions of living beings for their cellular respiration.

Whether it is forty, eighty or a hundred years, it hardly matters: oxygen kills us all in the end.

Firstly, let’s debunk a common misconception: oxygen cannot be breathed in at any concentration. We speak of oxygen toxicity when the percentage is too high or too low with respect to the optimal one for us, which is between 19 and 23%.

Below 19% oxygen concentration, our body quickly goes into hypoxia; an excess of breathed oxygen, on the other hand, has deleterious effects due to its strong oxidizing capacities and, therefore, increasing its concentration causes an increase in its electrochemical activity.

This is why, among other things, medical oxygen therapies are very delicate: pumping too much oxygen in a hurry can cause the formation of free radicals.

A radical is an atom or a group of atoms with unpaired electrons, that are known to be linked to aging. They are dangerous because they damage tissue, DNA and other biological molecules.

We are therefore faced with the so-called ‘oxygen dilemma’, which is well known in scientific circles.