Your respiratory system, or breathing system, includes the structures from your nose to your trachea and finally the alveoli in your lungs. Alveoli are the tiny pockets where oxygen and carbon dioxide are exchanged. This system is responsible for moving and exchanging oxygen in the air you breathe with the air in your lungs. Your brain and receptors in your active muscles exchange information to stimulate your respiratory system when you go from rest to exercise.
Increased Breathing Rate
Whether you are lying in bed, sitting down or making dinner, your body must convert the carbohydrates in your blood to a form of energy your cells can use called adenosine tri-phosphate, or ATP. You need a small amount of ATP for everyday activities compared to when you are exercising. When you transition from changing your clothes in the locker room to running on a treadmill, your muscles need more ATP. If you exercise for longer than three minutes, you are performing an aerobic activity. Your respiratory system senses the need for more oxygen because you need oxygen to make ATP during aerobic exercise. Your brain sends signals to your lungs to increase your breathing rate so you can inhale more air.
Oxygen and carbon dioxide exchange occurs at the smallest level of your breathing system, your alveoli. Your alveoli have very thin walls and are in direct contact with the thin walls of the capillaries in your lungs. When you breathe, blood stays in your capillaries, and air remains in your alveoli. Oxygen and carbon dioxide, however, move across their respective thin membranes. During exercise, the amount of oxygen leaving your alveoli and going into your blood increases. Likewise, the amount of carbon dioxide leaving your blood and entering your alveoli increases.
Inspiration, or the amount of air you breathe in, is dependent on the actions of your diaphragm, the muscles between your ribs and your abdominal muscles. During exercise, these muscles contract to a greater degree to open up your chest cavity so that more air can come into your lungs.
Expiration, or the amount of air you exhale, is also dependent on the actions of the internal muscles between your ribs and your abdominal muscles. These muscles powerfully contract on your ribs and your abdominal cavity to make your chest cavity very small. This enables you to exhale as much air as possible.
Tidal volume is the amount of air you breathe in or out in one breath. Vital capacity is the amount of air you can maximally inhale then maximally exhale, particularly important during high-intensity exercises. Lung volumes decline with age due to a decrease in the elasticity of your lung tissues. Regular aerobic exercise decreases this age-related change in lung volume.
About this Author
Paula Quinene has been writing since 2006. Her book, “Remember Guam,” won two Gourmand Cookbook Awards and she was featured in “Oxygen Fitness Magazine.” She’s certified by the American College of Sports Medicine, American Council on Exercise, was a certified strength and conditioning specialist and a CPR/First Aid instructor. She earned her bachelor’s degree in exercise and movement science from the University of Oregon.