Document: Breathing Rate
Abstract: Oxygen is essential to life. We use the oxygen we breathe and the food we eat to produce energy. Physical activity increases our need for energy; increasing the use of oxygen and nutrients.The body can store some of the things it needs to function. However, oxygen cannot be stored for more than a few minutes at a time.At rest the blood holds about a quart of dissolved oxygen, but it is constantly being used by the cells to produce energy during respiration. The respiratory system must work all of the time to supply enough oxygen to the body.