When does being out of breath become a problem?

Written by: Dr John Gerry Coghlan
Published: | Updated: 24/07/2019
Edited by: Bronwen Griffiths

Everyone can get out of breath, for example when exercising vigorously. However, breathlessness may also occur when it shouldn’t and this usually indicates an underlying problem. Dr John Gerry Coghlan, a leading cardiologist, explains when breathlessness becomes abnormal and you need to see a specialist.

Breathlessness is a distressing sensation of not being able to “get one’s breath”, this can be particularly frightening if it occurs at rest or wakes you from your sleep, but it is also important if it prevents you from doing activities that a few days or weeks ago you could do easily. Breathlessness at rest is almost always serious and requires immediate medical attention. Any loss of the ability to exercise due to breathlessness, even if this occurs gradually, should be investigated, unless the explanation is obvious (for example when you have a cold).

Most commonly, abnormal breathlessness is caused by problems with the lungs and the heart, and that's where most people will look first. People are frequently told they've got asthma, are overweight or not exercising enough when they complain of breathless, but we always need to keep an open mind as there are many other ways of becoming breathless. Importantly asthma (except during an acute attack), being over-weight and lack of exercise do not cause you to become breathless doing things you could do comfortably a few months ago.

Different types of breathlessness and their causes

Breathlessness can differ as well in terms of how rapidly it comes on. In this sense, there are a few types of breathlessness:

  • Acute breathlessness – has a rapid onset, appearing over a matter of hours or days.
  • Chronic breathlessness – this occurs slowly, developing over a period of weeks or months.

Generally, the causes of acute and chronic breathlessness will be very different.

Common causes of acute breathlessness include:

  • Lung infections
  • The common cold
  • Flu
  • Bronchitis
  • Pneumonia
  • Asthma
  • Collapsed lung
  • Pulmonary embolism
  • Acute heart failure (when the blood supply to the heart is blocked off, the heart weakens and is no longer able to keep the lungs free of fluid, causing breathlessness)

Read more: what causes a lung to collapse?

Common causes of chronic breathlessness include:

  • Smoking damage
  • Airways disease, such as chronic bronchitis
  • Emphysema
  • Pulmonary fibrosis (scarring of the lungs)
  • A weakened heart (it is not able to clear fluid from the lungs efficiently)
  • Hypertension causing a ‘stiff’ heart (over time high blood pressure makes it more difficult to fill the heart with blood)
  • Heart valve problems (if a valve becomes too tight or too leaky, breathlessness can result)

All of the above affect the ability of the lungs to move air efficiently or to get oxygen to our bloodstream, causing breathlessness.

Less common causes of abnormal breathlessness

For example, we need to think of people with severe anaemia. People with anaemia may experience abnormal breathlessness because they do not have enough red cells in their blood to carry blood to the muscles. Therefore, even if their heart and lungs are working normally, they will still become breathless.

Additionally, people who suffer from thyroid disease may also experience abnormal breathlessness. This is because if the thyroid is severely overactive, the muscles can demand more oxygen than your heart and lungs can provide. Furthermore, people with kidney disease may become breathless as their kidneys are unable to expel fluids from the body which builds pressure in the lungs and increased blood pressure. In turn, this puts pressure on the heart, despite it being an otherwise healthy heart.

Therefore, there are many potential causes of abnormal breathlessness, and these all need to be investigated.


If you are concerned about your health or experience breathlessness, make an appointment with an expert.

By Dr John Gerry Coghlan

Dr John Gerry Coghlan is a leading consultant cardiologist based in London, who specialises in pulmonary hypertension and all aspects of cardiology, including complex breathlessness, arrhythmias, connective tissue disease (related to heart disease) and angina.

Dr Coghlan is an honorary senior lecturer at UCH London and a visiting consultant at Papworth Hospital Cambridge, where he performs balloon pulmonary angioplasty. He is also a visiting consultant at St Thomas' Hospital, Kings College Hospital, Royal United Hospital Bath, Queen Alexandra Hospital Portsmouth, Derriford Hospital Plymouth and Ulster Hospital Dundonald.

Dr Coghlan graduated from University College Dublin in 1983 and trained in cardiology at the National Cardiac Centre, Dublin, Harefield Hospital and The Royal Free Hospital, London. He is a founder member of the National Pulmonary Hypertension Physicians Association and developed the Royal Free National Pulmonary Hypertension Service.

He holds research interests in fields of pulmonary hypertension, cardiac imaging and ischaemic heart disease and has published over 200 papers in peer-reviewed journals. Throughout his career, he has won awards such as the Molloy prize in 1978 and a silver medal in surgery in 1983, amongst others.

View Profile

Overall assessment of their patients

This website uses its own and third-party cookies to collect information in order to improve our services, to show you advertising related to your preferences, as well as to analyse your browsing habits..