Breathlessness

What causes breathlessness?

Breathlessness is a symptom, and there are many possible underlying causes.

The 4 main causes are:

There are other reasons too. 

If you get breathless every day, you might be diagnosed with one of these causes. Often there’s more than one. And others can develop over time. If you notice changes in your breathing, tell your doctor. Conditions that cause long-term breathlessness can often be treated but some cannot be fully reversed.


Lung conditions

Lung conditions cause breathlessness in different ways. Some conditions cause the airways to become inflamed and narrowed, or fill the airways with phlegm, so it’s harder for air to move in and out of the lungs. Others make the lungs stiff and less elastic so it’s harder for them to expand and fill with air.

Lung conditions that cause long-term (chronic) breathlessness include:

Some lung conditions can also cause short-term (acute) breathlessness. These include:

  • a flare-up of asthma or COPD
  • a pulmonary embolism or blood clot on the lung
  • a lung infection such as pneumonia or tuberculosis
  • a pneumothorax or collapsed lung
  • a build-up of fluid in your lungs or the lining of your lungs – this might be because your heart is failing to pump efficiently or may be because of liver disease, cancer or infection

Heart conditions

Some people may experience long-term breathlessness due to heart failure. This can be due to problems with the rhythm, valves or cardiac muscles of the heart. Heart failure can cause breathlessness because the heart is not able to increase its pumping strength in response to exercise, or because the lungs become congested and filled with fluid. Often this is worse when lying flat so breathlessness due to heart failure can be worse at night or when asleep.

Heart conditions that cause acute breathlessness include:

  • a heart attack
  • an abnormal heart rhythm. You might feel your heart misses beats or you might experience palpitations

Find out more on the British Heart Foundation website


Anxiety

Some people feel short of breath when they’re anxious or afraid. This is a normal response by your body to what you think is a stressful situation – your body is preparing for action. As you get more anxious, you may start to breathe faster and tense your breathing muscles.

Your physical health can also impact on your mental health, especially if you are living with a lung condition. You might get anxious if you don’t feel in control of your condition. And if you have a condition, you may have symptoms that make you feel anxious. Sometimes the symptoms - like breathlessness, tightness in your chest or getting tired very easily - are similar to feelings of anxiety.

Panic attacks

When your body’s normal response is exaggerated, you get a rapid build-up of physical responses. This is a panic attack. As your body tries to take in more oxygen, your breathing quickens. Your body also releases hormones so your heart beats faster and your muscles tense. 

During a panic attack, you might feel you can’t breathe and:

  • have a pounding heart
  • feel faint
  • sweat
  • feel sick
  • have shaky limbs

  • feel you’re not connected to your body

Panic attacks can be very frightening if you feel you can’t breathe.


Being unfit

When we are unfit, our muscles get weaker. This includes the muscles we use to breathe. Weaker muscles need more oxygen to work, so the weaker our muscles, the more breathless we feel.

Being an unhealthy weight can also make us feel breathless.

  • If you’re underweight, your breathing muscles will be weaker.
  • If you’re overweight, it takes more effort to breathe and move around. Having more weight around the chest and abdomen restricts how much your lungs can move. If you have a body mass index of 25 or more, you’re more likely to get breathless compared to people with a healthy weight.

People who are severely overweight can develop obesity hypoventilation syndrome. This is when poor breathing leads to lower oxygen levels and higher carbon dioxide levels in their blood.


Other reasons

Other causes of long-term breathlessness include:

  • smoking
  • conditions that affect how your muscles work, such as muscular dystrophy, myasthenia gravis or motor neurone disease
  • postural conditions that alter the shape of your spine, and affect how your ribs and how your lungs expand. For example scoliosis and kyphosis
  • anaemia, when a lack of iron in the body leads to few red blood cells
  • kidney disease
  • thyroid disease

Getting out of breath can be very frightening. You may feel anxious about it or feel embarrassed about other people seeing. The good news is that you can get help. You can make a plan with your doctor to manage your breathlessness. You can learn control your breathing.

As long as it works, we all take breathing for granted. I am now aware of every breath I take and of its own quality. I have a great group of professionals around to help me and I am well supported by my family.” Chris, was diagnosed with COPD over ten years ago.

Next: Diagnosing breathlessness >

Download our breathlessness PDF (716 KB)

Last medically reviewed: November 2017. Due for review: November 2020

This information uses the best available medical evidence and was produced with the support of people living with lung conditions. Find out how we produce our information. If you’d like to see our references get in touch.