Although it is not unusual to get breathless when over-exerting yourself, finding that you have sudden or unexpected shortness of breath, or ongoing breathing difficulties, is often a sign that you have an underlying medical condition. It is therefore important to seek medical assessment of your breathlessness to determine whether you have a problem affecting your heart or lungs or whether there is another explanation for your symptoms.

Causes of Sudden Breathlessness

There are many causes of breathlessness that are not related to the heart. These include many diseases of the lungs such as asthma or chronic obstructive airways disease and infections of the lungs. Breathlessness can also be caused by anaemia. Lifestyle factors such as being overweight or being unfit may also cause breathlessness.

A range of cardiac causes can lead to breathlessness. Sometimes breathlessness can occur during a heart attack. After a heart attack if the heart muscle has been significantly damaged then it may not be able to pump properly (see Heart Failure). This then leads to fluid accumulating in the lungs causing breathlessness. Angina can sometimes lead to breathlessness on exercise with or without chest pain. A common presenting symptom of heart valve disease is breathlessness. Diseases affecting the heart muscle (cardiomyopathies) can also lead to breathlessness.  Palpitations can often be associated with shortness of breath.

Causes of Chronic Breathlessness

Several health problems that give rise to sudden shortness of breath can also cause ongoing problems with breathlessness. This is the case with asthma, chronic obstructive pulmonary disease, heart failure and arrhythmias. However, additional respiratory and cardiac conditions can also cause you to become short of breath in the longer term, as may occur in lung cancer, bronchiectasis and if the main valve in your heart narrows. Besides a problem with your heart or lungs, other common causes of chronic breathing difficulties are obesity, poor fitness and anaemia. Shortness of breath occurs when you are carrying extra weight because your lungs need to do more work, but the increased weight on the chest wall can also make it difficult for your lungs to expand. Meanwhile, in anaemia, reduced levels of haemoglobin make it more difficult for your red blood cells to transport oxygen around your body.

Diagnosing Breathlessness

There are many causes for breathlessness and it is important to determine the correct diagnosis to enable to the correct treatment to be given. To determine the exact cause of your breathlessness will often need specialised tests after taking a full history of your symptoms and examining you. Investigations will usually include a resting ECG at the time of the consultation, a chest x-ray, an echocardiogram and blood tests. Other more specialised tests may be recommended depending on the exact nature of your symptoms.