What is Causing my Breathlessness?

Breathlessness is super common! 25% of patients seen by doctors in the clinic are there because of breathlessness. The medical term for it is dyspnea. Breathlessness or shortness of breath is a common clinical manifestation of many underlying conditions.

So how do we define it?

  • Dyspnea is an individual's interpretation of breathing discomfort. It is a subjective symptom that can be acute or chronic.
  • Acute dyspnea is sudden in onset and severe in nature, and often indicates a life-threatening health condition. Sometimes, chest tightness is an accompaniment of acute dyspnea.
  • Chronic dyspnea is shortness of breath lasting for more than four months.

There is no single cause. Dyspnea may indicate a problem in the lungs, heart, or a combination of both. It can also be due to anemia, anxiety, drugs, malignancy, renal failure, thyroid disease, diabetes, sepsis, pregnancy, and trauma!

I’ve broken down the cause into 3 areas:

  1. Lung (respiratory) causes
  2. Heart causes
  3. Others

1. Lung causes of breathlessness

Asthma. Asthma is the inflammation of lung airways commonly caused by allergens, physical activity, infection, and environmental irritants. People with asthma exhibit noisy wheezing, high breathing rate, and shortness of breath.

COPD. Chronic Obstructive Pulmonary Diseases (COPD) is a group of lung problems characterized by chronic inflammation and obstruction of the lower airways. Bronchitis and emphysema are examples of COPD. Difficulty of breathing and chronic productive cough are the classic signs of COPD.

Pneumonia. Pneumonia is the inflammation of the lungs marked by cough, fever, and pain on deep breathing. Dyspnea is also a predominant clinical manifestation, particularly in older people aged 65 and above, diffused type of pneumonia and viral pneumonia.

Pulmonary embolism. Pulmonary embolism occurs when there is blockage of lung blood vessels as a result of a clot or air. It is a life-threatening condition that may result in death when managed poorly. People with blood-clotting problems and following surgery are at risk of developing pulmonary embolism. Sudden shortness of breath, shallow breathing, chest pain, increased heart rate, and spitting of blood are common signs and symptoms of pulmonary embolism.

2. Heart causes of breathlessness

Heart failure. Heart failure is a state when the heart loses its ability to pump blood effectively throughout the body. People with heart failure have difficulty breathing, pale skin, swelling of the legs, and fatigue/tiredness. Heart failure is often a complication of other health conditions such as high blood pressure and heart attacks.

Coronary heart disease (CHD). Coronary heart disease is a condition when the heart receives deficient blood supply as a result of blocked coronary arteries (the main blood vessels supplying the heart). The blockage is caused by fatty-build up over a period of time. CHD is a serious health disorder since it can cut off the blood supply to the heart completely, leading to a heart attack. Breathlessness, particularly during exertion, is a classic sign of CHD.

3. Other causes of breathlessness

Anemia. Anemia refers to low red blood cells in the body. The role of red blood cells is to carry oxygenated blood to body tissues to maintain their function. Because the tissues and organs receive less oxygen, people with anemia exhibit shortness of breath, fatigue, and irregular heartbeat.

Psychiatric illness. Dyspnea can be psychological. Like pain, dyspnea can be influenced by the state of mind. People who panic and feel anxious may struggle to breathe. Difficulty of breathing caused by psychological illness is called psychogenic dyspnea.

Drugs. Certain medications cause spasms in the large airways affecting breathing. Beta-blockers, Non-steroidal anti-inflammatory drugs (NSAIDs), and aspirin, when given in high doses, can precipitate shortness of breath.

Cancer. People with cancer may present with shortness of breath as a complication of a disease or a side effect of a treatment such as chemotherapy. They also suffer more pronounced dyspnea upon exertion or physical activity.

Kidney failure. People with late-stage kidney failure may struggle to breathe. Shortness of breath in kidney failure is a result of fluid accumulation in the lungs. People with end-stage kidney disease lose their ability to excrete waste products leading to fluid build-up.

Thyroid disease. Both hyperthyroidism and hypothyroidism affect the respiratory system. The underactive thyroid gland (hypothyroidism) causes respiratory muscle weakness and reduces lung function. On the other hand, an overactive thyroid (hyperthyroidism) can increase respiratory drive, particularly on exertion.

Diabetic ketoacidosis (DKA). Diabetic ketoacidosis is a serious complication of diabetes marked by an increased level of ketones in the body. Too many ketones can make the body acidic, which may impair significant bodily functions. Dyspnea is a common symptom of DKA. It is the body's natural way to remove excess carbon dioxide in the body system.

Sepsis. Sepsis is a term used to describe an infection spread throughout the body. It is a medical emergency that can lead to multiple organ failure or even death. Shortness of breath and altered mental status are systemic clinical symptoms of people with severe sepsis.

Pregnancy. Dyspnea in pregnancy is an expected physiological – rather than a pathological – manifestation in late pregnancy. It is a common complaint symptom of pregnant women by the third trimester, particularly 31 weeks and beyond, due to the growing baby compressing the diaphragm.

Trauma. Dyspnea is a common presenting symptom in a thoracic emergency requiring immediate treatment. For example, people with pneumothorax or a collapsed lung manifest sudden shortness of breath with one-sided chest pain.

Other Causes. There are many other causes of dyspnea. Any trauma, malformation, cancer, and disease in the ear, throat, and nose can affect breathing resulting in dyspnea. Neuromuscular conditions such as sclerosis may affect muscle strength including the ventilatory muscles in the chest can also cause difficulty breathing.


Dyspnea is a complex symptom that may be common for healthy individuals, such as when performing exercise. Similarly, people who experience fear, anxiety, or strong emotion may seem breathless. Dyspnea has numerous potential causes therefore, a good physical examination, precise history taken by your cardiologist, and tests play a key role in making the correct diagnosis and identifying the cause.

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