Respiration is a combination of chemical reactions which release energy inside living cells. This energy is used for growth, making new materials, movement and, in mammals and birds, the production of heat.
Glucose + Oxygen -> carbon dioxide + water + (energy)
Glucose + oxygen - These are brought to the respiring cells to the blood stream.
Carbon Dioxide - Is taken by the blood to the lungs to be breathed out.
Water - Passed to the blood and is lost as sweat, moist breathe and urine
Energy - Is used for muscle contraction, metabolism and maintaining temperature.
We breathe in 21% of oxygen, 0.003% of carbon dioxide and 79% of nitrogen.
We breathe out 18% of oxygen, 3% of carbon dioxide and 79% of nitrogen.
Glucose = Energy + Lactic acid
When the body doesn't have enough time to take in oxygen when exercising it respires anaerobically through converting glucose into energy. It is a quick way of gaining energy but causes lactic acid to form in between our muscles. When we have stopped exercising we have to take deep breathes to regain enough oxygen to break down the lactic acid.