When you exercise, your breathing rate increases. This is true regardless of whether you exercise with stationary methods, such as lifting weights, or with an aerobic, such as jogging or cycling. Clearly, an active body needs more oxygen than a body at rest. The reason for this lies in the complex chemical processes in your muscles and your bloodstream.
4 reasons why we need more oxygen when we train
Greater energy needs
Your body needs oxygen at all times. O2 and glucose are the building blocks of your body's energy. You need them to get your heart pumping blood, to keep your lungs inhaling and exhaling, and to allow all other organs and cells to function. Each of these activities consumes energy that must be replaced in part by absorbing more oxygen.
When you exercise, your muscles move more vigorously than when you are at rest. Your metabolic rate increases. They need more energy, so they produce more of the chemical energy molecule ATP. You need oxygen to make ATP, so the more you produce, the more 02 your body needs.
Decreased oxygen stores in the blood
Oxygen reaches the muscles and other parts of the body through the bloodstream. O2 dissolves in plasma, where most of it, approximately 98.5 percent, according to information from Eastern Kentucky University, adheres to hemoglobin molecules. While you are resting, only about 20 to 25 percent of the hemoglobin molecules give up their oxygen to the tissues. A large amount of oxygen remains in reserve in the bloodstream.
As you begin to exercise, you use up these stores and the saturation of oxygen and hemoglobin in the bloodstream drops dramatically. You need to take in more O2 to make up for this loss and meet your body's increased need for O2.
Decreased partial pressure
The partial pressure of oxygen, or PO2, refers to the individual pressure exerted by oxygen in a mixture of gases or substances. As oxygen leaves the bloodstream and enters the tissues, the PO2 in the bloodstream drops. At lower PO2 levels, red blood cells make more of a substance called 2'3-diphosphoglycerate . The increased presence of this substance helps alter the structure of hemoglobin in such a way that it gives up your oxygen more easily.
The Bohr effect
The faster release of oxygen from hemoglobin, otherwise described as a reduced level of oxygen-hemoglobin saturation, is favored by other conditions in an exercising body. As your muscles produce additional ATP, the basic unit of energy, they also produce waste products. These are mainly carbon dioxide or CO2 and hydrogen ions or H +. Christian Bohr discovered in 1904 that increasing concentrations of these substances stimulate hemoglobin to release oxygen molecules . This principle, the Bohr effect, facilitates the exercise of the muscles and other active tissues to extract 02 from the bloodstream in greater quantities, but it also means that you need to replenish your oxygen supplies much faster.
