We need oxygen to live! Oxygen is what makes our bodies function, without it humans, animals, plants and even fish would all die without it. Oxygen is brought into your lungs when you breathe, and it is then transported by red blood cells to the entire body. It is needed to burn the fuel [sugars and fatty acids] in our cells to produce energy. So you can see that oxygen is important to every cell in your body for growth, maintenance and recovery.