Water or H2O contains oxygen

I remember hearing that yawning is a sign that the brain needs oxygen.

I was thinking about how to get more oxygen to the brain when the inhaled oxygen is not enough for some reason.

One natural product came to mind, it is already here and at least for now quite easily available to people, water or H2O contains oxygen combined with a few hydrogen atoms.

The reaction of oxygen with another substance is called oxidation, combustion.
In the human body, inside each cell there is also a place where these combustion reactions take place it called a mitochondrion.

In the mitochondrion, oxygen reacts with, for example, carbohydrates obtained from food, and thus energy is obtained for,  muscles.

That is, the water you drink goes into the cell's mitochondria
and there inside the cell, oxygen and hydrogen are first separated from each other oxygen is used for combustion, i.e. energy production.
and the hydrogen, which is now a gas unnecessary for the body ... is breathed out ...
and the remaining the hydrogen easily reacts with the oxygen in the air, so hydrogen oxidizes (that is it burns) and the burning of hydrogen produces more water.

There is a lot of water on Earth, at least 70-80 percent.