Regardless of whether you're asleep or awake, running a marathon or watching television on your couch, your lungs are constantly at work. The constant rhythm of inhaling and exhaling plays an integral role in your body regarding oxygen supply. In fact, your respiratory system constantly adjusts its speed based on your current level of activity to maintain homeostasis within the body.
Respiratory Rate When Resting
Your respiratory rate differs significantly between times of rest and times of physical activity, such as exercise. When your body is at rest, less energy is needed to fuel the cells for muscle movement and other functions associated with movement. This means the lungs only need to supply enough oxygen to supply basic cell functions, such as your heart cells to maintain your heartbeat and the cells of the digestive tract for digestion. Less oxygen need results in a smooth and slow inhale and exhale to and from the lungs.
Exercise and Energy Use
When you exercise, energy needs increase significantly. The cells of your muscles especially use up the oxygen in the blood at a much greater rate to keep up with the energy needs of physical activity. Not only do muscle cells require more energy for work, but cells involved with recovery of the muscle tissue and cells like osteoblasts that strengthen your bones in response to stress from exercise also increase their energy usage.
Lung Activity With Exercise
To keep up with the increased energy needs during exercise, your brain must communicate with both your heart and lungs to increase the level of oxygen and speed up the delivery of both the oxygen and nutrients needed to create energy at the cellular level. The increase in respiratory rate changes how fast your lungs draw oxygen from your surrounding environment. The air is then taken into the lungs where it diffuses into the bloodstream. How much the respiratory rate increases is dependent on how intensely you exercise. The more intense the exercise, the faster your lungs breathe in and exhale out.
Carbon Dioxide Removal
An accelerated need for oxygen results in an accelerated production of carbon dioxide during exercise. When oxygen combines with broken down nutrients to create energy, it produces by-products like water and carbon dioxide. While the water is eliminated through processes like sweat and urination, the carbon dioxide needs to be eliminated out the same way oxygen came in. The carbon dioxide is transported into the veins where it is taken to the lungs. From the lungs, it passes back out of the respiratory system into the surrounding environment. Since energy use takes time to return to normal after exercise, the increased breathing rate will continue until energy use returns to a normal resting rate and the excess carbon dioxide is eliminated from the bloodstream.
