The respiratory system is composed of the lungs and bronchi on the lower end, and the trachea and sinuses on the upper end. The respiratory system works closely with the circulatory system, which includes the heart and blood vessels, to distribute oxygen throughout the body and remove wastes like carbon dioxide from the tissues. Changes to one system cause changes in the other, according to "The Principles of Anatomy and Physiology." Exercise strengthens the respiratory and circulatory systems so they can do their jobs more efficiently.
How the Respiratory System Works
The lungs have a network of air sacks, called alveoli, surrounded by tiny blood vessels called capillaries. When we inhale, air fills the alveoli and oxygen filters into the blood vessels. The oxygen is then carried to the heart and out to all the tissues in the body by the circulatory system. When we exhale, carbon dioxide filters into the alveoli from the capillaries, and out of the body through the nose and mouth. The exchange of carbon dioxide and oxygen occurs constantly, with every breath.
Types of Exercise
In respiratory terms, exercise falls into two categories, according to "The Physiology of Sport and Exercise," and these are aerobic and anaerobic. The word aerobic means "air." Aerobic exercises, such as running and cycling, cause an increase in your heart and breathing rate. Anaerobic means "without air." Anaerobic exercises, such as weight training, generally do not increase the heart and breathing rates. One exception may be yoga, an aerobic exercise, which incorporates breathing techniques as part of the exercise.
Aerobic Exercise and Respiration
Aerobic exercise places immediate energy demands on the body, because the muscles need more oxygen to fuel activity. To meet these demands, the heart must beat faster to deliver fresh blood to your muscles, and the lungs need to work faster to get more oxygen into the blood and remove carbon dioxide. Over time, the heart and lungs adapt to the increased energy demand. The heart pumps more blood with each beat, and the air sacs in the lungs increase their capacity and become more efficient at filtering oxygen and carbon dioxide. This is why, over time, you are able to increase the intensity of your aerobic exercise session or become less winded during exercise. The affects of aerobic exercise carry into resting periods as well. People who do regular aerobic exercise have lower heart rates and slower breathing rates than those who don't, according to "The Physiology of Sport and Exercise."
Anaerobic Exercise and Respiration
With the possible exceptionof yoga, anaerobic exercise does not condition the lungs, but it does strengthen the muscles that support respiration. The diaphragm muscle controls the lungs by contracting downward and expanding the space in the chest cavity, which causes the lungs to expand and take in air. When the diaphragm pushes upward, it contracts the cavity and causes the lungs to contract and release air. The interior and exterior obliques also assist with breathing by expanding and contracting the rib cage. Anaerobic exercises that work the core strengthen the muscles that support respiration. Strengthening the upper back, chest and shoulder muscles keeps the spine in proper alignment, which keeps your rib cage from compressing your chest cavity, according to the American Council on Exercise.
References
- "Physiology of Sport and Exercise";Jack H. Wilmore, PhD. & David L. Costill, PhD.;1999
- "Principles of Anatomy and Physiology;" Gerard J. Tortora and Bryan H. Derrickson; 2008
- "Personal Trainer Manual;" American Council on Exercise; 2000
