Quick answer. Shortness of breath can come from lung conditions like asthma, heart problems, anxiety or anaemia. Sudden severe breathlessness, especially with chest pain or blue lips, is an emergency — call 995 immediately.
Breathlessness, or feeling unable to get enough air, is a very common symptom. It can be mild and harmless or a sign of a serious heart or lung problem.
This guide explains the usual causes of shortness of breath, the warning signs that need emergency care, and which specialist can help if symptoms persist.
At a glance
| Possible cause | What it may suggest | Urgency |
|---|---|---|
| Sudden severe breathlessness with chest pain or blue lips | Heart attack, lung clot or collapsed lung | Emergency – call 995 now |
| Wheezing, cough and tight chest, often with triggers | Asthma or COPD flare-up | Urgent – same-day care |
| Breathlessness on lying flat, with ankle swelling | Heart failure | See a doctor soon |
| Breathlessness with fever and cough | Chest infection or pneumonia | See a doctor soon |
| Breathlessness with anxiety or after exertion only | Anxiety, poor fitness or mild anaemia | See a doctor to confirm |
What shortness of breath feels like
Shortness of breath (also called dyspnoea) can feel like tightness in the chest, having to work hard to breathe, or simply not getting enough air. It may come on suddenly or build up over days to weeks. Noting whether it happens at rest, on exertion, or when lying flat helps your doctor find the cause.
When it's an emergency
Call 995 immediately if breathlessness comes with any of these red flags:
- Sudden, severe difficulty breathing that does not ease
- Chest pain or pressure along with the breathlessness
- Blue or grey lips, face or fingertips
- Choking, gasping, or inability to speak in full sentences
- Confusion, drowsiness or fainting
These can signal a heart attack, a clot in the lungs, a severe asthma attack or a collapsed lung. Call 995 for an ambulance — do not delay or drive yourself.
Common causes
Common causes of breathlessness include asthma, chest infections, chronic obstructive pulmonary disease (COPD), obesity, poor physical fitness and anxiety. Anaemia (low blood count) and being out of shape can cause breathlessness on exertion. Many of these are manageable once correctly diagnosed.
Serious causes to rule out
Serious causes include heart failure, heart attack, a blood clot in the lungs (pulmonary embolism), pneumonia, a collapsed lung and severe asthma attacks. Breathlessness that comes on suddenly, that worsens when lying flat, or that is paired with chest pain, swelling or coughing up blood needs prompt medical assessment.
Which specialist should you see?
For persistent or unexplained breathlessness, your GP can examine you and arrange initial tests. If a lung cause is likely, see one of the respiratory physicians for lung function tests and imaging. If a heart cause such as heart failure is suspected, the cardiologists can assess your heart with an ECG and echocardiogram.
How breathlessness is diagnosed
Assessment usually starts with your history and a physical examination, including listening to your heart and lungs and checking your oxygen levels. Common tests include a chest X-ray, blood tests, ECG, lung function (spirometry) tests and sometimes an echocardiogram or CT scan. The right combination depends on whether a heart, lung or other cause is suspected.
What to expect at the appointment
Your doctor will ask how the breathlessness began, whether it came on suddenly or built up over days to weeks, and what brings it on, such as exertion, lying flat at night, or anxiety. They will ask about cough, wheeze, chest pain, ankle swelling, fever and any history of asthma, heart disease or smoking. The examination includes listening to your heart and lungs and checking your oxygen level with a finger probe. Common first tests are a chest X-ray, blood tests, an ECG and lung function (spirometry) tests, with an echocardiogram or CT scan added if a heart or clot cause is suspected. It helps to note how far you can walk before becoming breathless and how this compares with a few weeks ago.
How to prepare and self-manage
If you already use an inhaler for asthma or COPD, bring it to the appointment and know how often you have needed it, as this tells the doctor how well controlled you are. Between visits, simple steps can help mild breathlessness: stay active within comfortable limits to build fitness, keep to a healthy weight, and avoid smoke and known triggers such as dust or strong fumes. If anxiety drives breathlessness, slow, controlled breathing can ease an episode, but recurrent symptoms still deserve a check to rule out other causes. Never ignore breathlessness that is steadily worsening, wakes you at night, or comes with ankle swelling or chest pain.
Special situations
Some situations need extra care. In pregnancy, a degree of breathlessness is common, but sudden or severe symptoms, calf pain and swelling, or chest pain should be assessed urgently, as the risk of clots is higher. Older adults and people with heart or lung disease can deteriorate quickly, so a clear change from their usual baseline should not be brushed aside. In children, fast breathing, drawing in of the chest, or blue lips are warning signs needing urgent care. Anyone with new breathlessness alongside chest pain, coughing up blood, or fainting should seek emergency assessment.
Common questions
When should I call 995 for breathlessness?
Call 995 for sudden, severe difficulty breathing that does not ease, breathlessness with chest pain, blue or grey lips, an inability to speak in full sentences, or confusion, drowsiness or fainting.
Can anxiety alone cause shortness of breath?
Yes, anxiety and panic can cause genuine breathlessness with rapid breathing. Because heart and lung causes can look similar, though, it is worth having persistent symptoms assessed to confirm the cause.
Related guides
- Best Respiratory & Lung Clinics in Singapore — our editorial shortlist
- Chest pain
- Difficulty swallowing
- Abdominal pain
Sources
- NHS – Shortness of Breath
- SingHealth – Heart Failure
- HealthHub Singapore – Asthma
- Mayo Clinic – Shortness of Breath
- NUH – Respiratory and Critical Care Medicine
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