Your breathing rate during exercise reflects the demands of physical exertion on your body. Your increased activity will increase the need for energy and oxygen, which you can detect by a change in your breathing rate. Because oxygen is needed by all cells, several mechanisms exist to ensure all cells have adequate supplies. Rather than one part of the body controlling breathing, several areas are capable of initiating changes in respiratory system function.
Biological Control
Several biological mechanisms control your breathing rate. The act of breathing is an involuntary response controlled by your central nervous system, which includes your brain and spinal cord. The nervous system also has a network of sensors in the body that provides feedback to the nervous system regarding your current state. For example, your carotid arteries and aorta can send signals to the brain regarding the concentration of carbon dioxide and oxygen. It can alter your breathing rate to increase or decrease it depending upon the concentration.
Energy Production
Sensors in the muscular system also provide feedback to stimulate heavier breathing. Your muscles require energy in order to function. Your body can produce energy with or without the presence of oxygen, but energy production in the presence of oxygen yields 36 or 38 ATP molecules, whereas production without oxygen produces two ATP molecules. ATP, or adenosine triphosphate, the energy currency of the body. In an attempt to increase the body's efficiency, your muscles will signal the brain to increase the breathing rate.
External Factors
If you are exercising in humid or smoggy conditions, your body will signal your respiratory system to breathe harder. Moisture molecules and particulate matter displace oxygen molecules when you take a breath, resulting in less oxygen uptake. The demands for oxygen are high during exercise. These external factors impair the body's ability to deliver oxygen. It will therefore compensate by making you breathing harder.
Internal Factors
If you come into contact with allergens while exercise, your breathing rate might change due to the constriction of airways. The allergic response releases histamine into the body, which initiates an increase in breathing rate. The restriction of air flow will likely cause you to breathe more rapidly. Another internal factor concerns exercise-induced asthma. While the exact mechanism is not known, the effects are similar to asthma in response to allergies, explains MayoClinic.com. You might wheeze or cough excessively. The effects on your respiratory system will cause you to breathe harder. Air pollution and extreme weather conditions are believed to be possible triggers.
References
- "Human Physiology: From Cells to Systems"; L. Sherwood; 2008
- National Heart Blood and Lung Institute: What Controls Your Breathing?
- University of Wisconsin: Chapter 8: Cellular Respiration
- U.S. Environmental Protection Agency: Smog -- Who Does It Hurt ?
- MayoClinic.com: Exercise-Induced Asthma - Causes
