Your respiratory system maintains homeostasis during exercise by increasing activity in your lungs, respiratory muscles and airways. Exercise increases your body's demand for chemicals needed for energy production and temperature regulation. Your respiratory system also works hard to rid your body of cellular toxins that accumulate during exercise. Regular exercise enhances respiratory system functioning, which reduces the amount of respiratory effort required both during exercise and at rest.
Carbon Dioxide Expulsion
Your muscles increase energy production during exercise, and carbon dioxide is a toxic byproduct of energy production. Rising carbon dioxide levels stimulate chemoreceptors, which regulate respiratory activity by stimulating respiratory centers in your brain. Elevated carbon dioxide levels during exercise trigger the chemoreceptor reflex, which speeds up respiration. During accelerated respiration, your circulatory system and lungs work hard collecting carbon dioxide from cells throughout your body. Your lungs absorb carbon dioxide through small sacs, called alveoli, and you expel the toxic gas each time you exhale during exercise.
Oxygen Intake
Your respiratory system works hard to balance the amount of oxygen and carbon dioxide in your body. During exercise your respiratory system increases the amount of oxygen you take in, and the amount delivered to working tissues in your body. Oxygen demands increase during exercise, because your muscles produce energy from oxygen in your blood. Therefore, more blood flows to working muscles during exercise. Oxygen intake also helps prevent overheating as temperature rises in your muscles during exercise. Your lungs capture oxygen each time you inhale, and deliver it to working muscles through your blood vessels.
Muscle Contractions
Respiratory muscles contract more frequently during exercise. Your diaphragm and external intercostal muscles contract, and fill your lungs with air each time you inhale. Pectoral and neck muscles contract during forced inhalation, which occurs whenever you take deep breath. Exercise may involve passive or forced exhalation, depending on the intensity of the activity. Forced exhalation occurs during strenuous exercise, and helps your body get rid of more carbon dioxide each time you breath out. Your abdominals, internal intercostals, middle and lower back muscles contract during forced exhalation.
Airways and Mucus
Oxygen and carbon dioxide flow in and out of your body through 23 airway divisions. Larger airways include the trachea, bronchi and bronchioles. Smaller airways include the terminal and respiratory bronchioles, alveolar ducts and alveolar sacs. Excessive mucus accumulation in your airways can inhibit breathing and respiration, and increase your risk of infections. Exercise exposes your airways to rapid gusts of air that help clear mucus. However, individuals with asthma may have airways that are sensitive to allergens and irritants. During exercise, your airways might swell and increase mucus production, if you have uncontrolled asthma.
References
- Cardiovascular Physiology Concepts; Chemoreceptors; Richard E. Klabunde, Ph.D.
- The Franklin Institute: Respiratory System - Oxygen Delivery System
- Illinois Wesleyan Athletic Training; Respiratory Regulation During Exercise; Bill Kauth, Ph.D
- Curoservice; The Respiratory Airways; April 2011
- The Ohio State University Medical Center: Asthma and Exercise
