Oxygen is necessary for every cell because it releases energy from food that cells need to function.
The primary role of oxygen is to provide energy to the body . Everything happens at the cellular level, in the mitochondria, which are real energy powerhouses: with oxygen, they transform the nutrients from digestion into energy that can be directly used by the cells. In the presence of oxygen, a glucose molecule can give 36 units of energy, but without oxygen, it will only produce 2. Oxygen is also involved in the fight against pathogens and in the control of free radicals.