1. Initiation of exercise
-
At the start of exercise, there is an abrupt increase in breathing due to neural changes that send excitatory impulses to the dorsal respiratory group (DRG) of the medullary respiratory center in the medulla. These changes include (1) anticipation of the activity, which stimulates the limbic system; (2) sensory impulses from proprioceptors in muscles, tendons, and joints; and (3) motor impulses from the primary motor cortex (precentral gyrus).
2. Moderate exercise
-
During moderate exercise, there occurs a more gradual increase in breathing due to chemical and physical changes in the bloodstream, , including (1) slightly decreased PO2, due to increased O2 consumption; (2) slightly increased PCO2, due to increased CO2 production by contracting muscle fibers; and (3) increased temperature, due to liberation of more heat as more O2 is utilized.
3. Asthma attack
-
The air passages in the lungs become narrow due to inflammation and tightening of the muscles around the small airways. Airway obstruction may be due to smooth muscle spasms in the walls of smaller bronchi and bronchioles, edema of the mucosa of the airways, increased mucus secretion, and/or damage to the epithelium of the airway.
4. Abrupt ascent into high altitudes
-
The reduced oxygen content of the blood causes breathing instability at altitude, with periods of deep and rapid breathing alternated with central apnea. Since the blood from all areas of the lungs is relatively short on oxygen or hypoxic, the lungs respond to this by tightening the blood vessels.
5. Pneumonia
-
The lungs’ air sacs (alveoli) are filled with pus and fluid, which makes breathing painful and makes it hard for the oxygen to enter the bloodstream that limits oxygen intake.
6. Paralysis of phrenic nerve
-
Phrenic nerve palsy most commonly is caused by compression or invasion of the nerve by a neoplasm. As a result, the diaphragm weakens and when paralyzed, the diaphragm affects your lungs’ ability to exchange air.
7. Severe tuberculosis with resulting lung scar tissue
-
Tuberculosis scarring causes the loss of parenchymal tissue (the spongy part of the lung) ultimately leading to restrictive spirometry or restrictive lung disease. Hence, may result in breathing difficulty, reduced lung capacity, and abnormal spirometry patterns.
8. Severe anemia
-
Due to low levels of hemoglobin, adequate oxygen is prevented from reaching the brain. Severe anemia causes hyperventilation and a rapid heartbeat, which is why the lungs overcompensate in order to bring in more oxygen, causing breathing difficulties.
9. Advanced COPD (chronic obstructive pulmonary disease)
-
The airways in your lungs become inflamed and thicken, and the tissue where oxygen is exchanged is destroyed, which results in the decrease of flow of air in and out of your lungs. As the disease advances/worsens, the severity of the shortness of breath increases.
10. Advanced pregnancy
-
Pregnant people, especially those in ages 35 or up, often breathe faster due to increases in the hormone progesterone which is a respiratory stimulant, meaning it causes a person’s breathing to quicken. As the uterus grows over the trimester, the baby may press the diaphragm which makes it even harder to breathe.
References:
American Lung Association. (2022, October 25). Learn About COPD. Retrieved from
https://www.lung.org/lung-health-diseases/lung-disease-lookup/copd/learn-about-copd
Baillie, K. (n.d.). Breathing at High Altitude. Retrieved from
https://www.altitude.org/high-altitude#:~:text=leaving%20the%20lungs.-,At%20high%20altitude%2C%20there%20is%20less%20oxygen%20in%20the%20air,short%20on%20oxygen%20or%20hypoxic.&text=Unfortunately%2C%20the%20lungs%20still%20respond,by%20tightening%20the%20blood%20vessels.
Cleveland Clinic. (2021, May 12). Phrenic Nerve. Retrieved from
https://my.clevelandclinic.org/health/body/22270-phrenic-nerve
Nall, R. (2022, January 30). Causes of shortness of breath during pregnancy. Retrieved from
https://www.medicalnewstoday.com/articles/322316#causes
Oghan et al. (2013). Effects of High Altitude on Sleep and Respiratory System and Theirs Adaptations. ScientificWorldJournal, 2013. https://doi.org/10.1155/2013/241569
Texas Medical Institute. (2020, July 24). 10 Symptoms of Anemia You Shouldn’t Ignore. Retrieved from
https://www.texasmedicalinstitute.com/10-symptoms-of-anemia-you-shouldnt-ignore/
Thomas, E. (2020, May 13). Lungs may still have scars left behind by tuberculosis, shows study. Retrieved from
https://researchmatters.in/news/lungs-may-still-have-scars-left-behind-tuberculosis-shows-study
Tortora, G. & Derrickson, B. (2014). Principles of Anatomy and Physiology (14th ed.). New Jersey, NJ: Wiley
WHO. (2022, May 11). Asthma. Retrieved from https://www.who.int/news-room/fact-sheets/detail/asthma
WHO. (2021, November 11). Pneumonia. Retrieved from
https://www.who.int/news-room/fact-sheets/detail/pneumonia
Yashoda Hospitals. (2019, January 5). Does tuberculosis cause COPD, pulmonary fibrosis or restrictive lung disease?. Retrieved from
https://www.yashodahospitals.com/blog/does-tuberculosis-cause-copd-pulmonary-fibrosis-or-restrictive-lung-disease/