Breathless man holds chest.

Why do I get breathless?

Feeling short of breath is one of the most common symptoms of heart failure.[1] In the early stages of the condition many people feel breathless after exercising or when performing more strenuous activities such as mowing the lawn.

But if the condition advances, feeling breathless can become more common during everyday activities like climbing the stairs or taking a shower, and even resting.[2] Lying flat can also suddenly bring on shortness of breath for many people, interrupting their sleep and sometimes leaving them feeling anxious and tired.[2]

Lungs in heart failure fill with fluid.

Fluid accumulating in the lungs

As with most symptoms experienced by people with heart failure, feeling short of breath is a result of the heart becoming less efficient at pumping blood around the body over time. In particular, as the heart muscles weaken or stiffen they become less able to keep up with the supply of blood coming into and leaving the heart.[3]

This can cause blood to "back up" or accumulate in the tubes traveling from the lungs to the heart.[4] If this happens fluid can leak into and accumulate in the lungs.[4] 

Our lungs are complex organs that remove carbon dioxide and exchange it for oxygen, but they can’t do this easily when fluid builds up inside them. It is this that can leave people with heart failure feeling short of breath.[4]

It is also why people with this heart problem may feel more breathless lying down, because as they do, the fluid spreads across the surface of the lungs (imagine liquid in a bottle when it is upright and how it spreads out when you lie it on its side).[5]

So what can be done to manage breathlessness? 

  • A good place to start is to listen to your body. If you only become breathless when exercising, then learn to recognise when symptoms start and next time stop at the first sign of them. Exercising regularly is known to improve the performance of the heart so it’s good to find a level of activity that you can maintain.[6]
  • Talk to your doctor or healthcare team about finding an activity or exercise that is right for you. In general ‘movement exercises’ are much better for the circulation than exercises to build strength: so gentle cycling, walking or swimming are normally OK; whereas weight lifting and press ups are likely to be less effective.[3]
  • If you become breathless when doing everyday tasks like climbing the stairs or taking a shower, talk to your doctor or healthcare team about exercises that may help your breathing or whether your treatment is working properly. Also, whilst you may find it difficult, try to let your carer or friends and family help, since keeping up with everyday activities can help you feel more in control of your life.
  • If you become breathless when resting, it’s a good idea to talk to your doctor or healthcare team about how to manage this, as adjustment to your current treatment regimen may be needed.
  • If you feel breathless when lying down, try supporting yourself with several pillows so that you are lying in a more upright position.[5]


1) Heart Failure Matters. Warning Signs. Shortness of Breath. Available at: Last accessed November 2016
2) Bozkurt, B. and Mann, D.L. (2003) ‘Shortness of breath’, Cardiology Patient Page, 108(2), pp. 11–13. doi: 10.1161/01.CIR.0000075956.36340.78.
3) Royal Berkshire Department of Cardiology. Heart Failure: Information for patients. Available here: Last accessed November 2016.
4) Medline Plus. Pulmonary edema. Available here: Last accessed November 2016.
5) Heart Failure Matters. Warning Signs. Awakening short of breath/ needing more pillows. Available at: Last accessed November 2016.
6) Ponikowski P et al. 2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure. European Heart Journal (2016) 37, 2129-2200. DOI: ehw128. First published online: 20 May 2016.