Physical exertion increases the need for oxygen in the muscles. To meet the body's oxygen needs, the heart and respiratory rate increase in parallel with the level of physical exertion. Medical conditions affecting the heart, lungs or red blood cells can interfere with this adaptive process, leading to shortness of breath with exertion. Increasing shortness of breath with physical exertion may indicate a serious medical condition and warrants medical evaluation.
Asthma
Asthma causes inflammation, swelling and constriction of the airways, leading to reduced airflow through the lungs. People with asthma generally feel comfortable at rest and while performing everyday activities. With physical exertion, however, impaired airflow through the lungs may cause shortness of breath.
Among people with the asthma type called exercise-induced asthma, physical exertion frequently triggers an asthma attack, explains National Jewish Health. By pretreating with inhaled medication before strenuous activity, most patients with exercise-induced asthma can enjoy physically demanding athletic and recreational pursuits without experiencing the coughing, shortness of breath and wheezing of an asthma attack.
Heart Failure
Heart failure limits the capacity to increase oxygen delivery to the tissue in response to physical exertion. This impairment in heart function characteristically triggers shortness of breath with exertion, notes the American Heart Association. The severity of heart failure correlates to the amount of physical exertion a patient can tolerate without developing shortness of breath. With heart failure progression, decreasing levels of physical exertion provoke shortness of breath.
Anemia
Anemia is a medical condition characterized by an abnormally low number of red blood cells in the circulation. The red blood cells transport oxygen from the lungs to the body tissues and organs. Without sufficient red blood cells to transport inhaled oxygen, people with anemia commonly develop shortness of breath with physical exertion. Anemia can develop with many types of medical conditions and disorders, including genetic abnormalities of the red blood cells, iron deficiency and gastrointestinal bleeding, reports the National Heart Lung and Blood Institute. Restoration of a normal level of red blood cells alleviates shortness of breath with exertion in most people with anemia.
Chronic Obstructive Pulmonary Disease
Chronic obstructive pulmonary disease includes emphysema and chronic bronchitis. With COPD, extensive lung damage causes a persistent obstruction of normal airflow in the lungs. The airflow obstruction makes it difficult for people with COPD to obtain sufficient oxygen to meet the body's needs. Shortness of breath with exertion is a hallmark symptom of COPD, according to The Merck Manuals Online Medical Library. With COPD progression, tolerance for physical exertion decreases with increasingly severe shortness of breath. Although COPD remains an incurable disease, early diagnosis, treatment and not smoking can slow disease progression.
References
- National Jewish Health: Exercise-Induced Asthma
- American Heart Association: Congestive Heart Failure
- National Heart Lung and Blood Institute: Anemia
- The Merck Manuals Online Medical Library: Chronic Obstructive Pulmonary Disease, Symptoms and Signs
- "Harrison's Principles of Internal Medicine, 16th Edition"; Dennis L. Kasper, M.D., et al; 2004
