Heart Health
Understanding Angina: Warning Signs From the Heart
A simple guide to stable angina, unstable angina, variant angina, GTN spray, and when chest pain needs emergency help.
Patient information page | Last reviewed: June 2026
The quick answer
Angina is chest pain or discomfort caused by reduced blood flow to the heart muscle. It is not the same as a heart attack, but it can be a warning sign that the heart is not getting enough oxygen-rich blood.
Stable angina usually happens with exertion or stress and settles with rest or prescribed medicine. Chest pain that is new, worse than usual, happens at rest, or does not settle quickly needs urgent medical attention.
If chest pain is severe, persistent, or associated with breathlessness, sweating, faintness, nausea, or pain spreading to the arm, jaw, neck, back, or upper abdomen, seek emergency medical help immediately.
What is angina?
Your heart is a muscle. Like any muscle, it needs a steady supply of oxygen-rich blood.
The blood supply to the heart comes through the coronary arteries. If these arteries become narrowed, the heart may still get enough blood when you are resting. But when the heart works harder, it may need more blood than the narrowed arteries can deliver.
That shortage of blood and oxygen can cause angina.
Chest sensation
Angina may feel like pressure, tightness, heaviness, squeezing, burning, or indigestion-like discomfort.
Where it can spread
The discomfort may spread to the arm, shoulder, neck, jaw, back, or upper abdomen.
Not always pain
Some people notice breathlessness, unusual tiredness, sweating, or nausea more than chest pain.
A patient journey: three patterns of angina
To understand how angina can behave in real life, let us follow a patient called A.
A is walking uphill to the local shops. Halfway up, he feels a heavy tightness across his chest. He stops and sits down. He uses his prescribed GTN spray under his tongue. Within a few minutes, the pain settles.
This pattern suggests stable angina.
Stable angina is usually predictable. It often happens when the heart has to work harder, such as during walking uphill, climbing stairs, rushing, cold weather, emotional stress, or after heavy meals.
The key feature is that it usually settles within a few minutes with rest or prescribed angina medicine. Stable angina still needs medical review and treatment. It is a warning sign that the heart arteries may be narrowed.
A few months later, A is sitting in his chair watching television. Suddenly, the same chest pressure returns. This time he has not been walking or exerting himself. The pain feels stronger than usual. It does not settle as expected.
This pattern may suggest unstable angina.
Unstable angina is more serious because blood flow to the heart may have suddenly worsened. This can happen if a fatty plaque inside a coronary artery cracks and a small clot forms over it.
Unstable angina can be difficult to tell apart from a heart attack without urgent tests such as an ECG and blood tests.
Variant angina, also called Prinzmetal's angina or vasospastic angina, is less common.
In this type, the coronary artery suddenly tightens or spasms. This temporarily reduces blood flow to the heart. It often happens at rest, sometimes at night or early in the morning.
Variant angina can be painful and frightening. It needs medical assessment because treatment is different from typical stable angina.
Quick comparison guide
| Type of angina | When does it happen? | Does rest or GTN help? | What should I do? |
|---|---|---|---|
| Stable angina | Usually during activity, stress, cold weather, or after heavy meals. | Usually settles within a few minutes. | Follow your angina plan and tell your doctor if symptoms change. |
| Unstable angina | At rest, new symptoms, worsening symptoms, or symptoms that last longer. | May not settle, or may come back quickly. | Seek emergency medical help. |
| Variant angina | Often at rest, sometimes at night or early morning. | May respond to medicines that relax the artery spasm. | Needs urgent doctor review and a clear treatment plan. |
How to use GTN spray for angina
If you have been prescribed GTN spray or tablets, follow the instructions given by your doctor.
A common plan is:
- Stop what you are doing.
- Sit down, because GTN can make you dizzy or light-headed.
- Use your GTN spray or tablet as prescribed.
- Wait 5 minutes.
- If the pain is still there, use a second dose as prescribed.
- If the pain is still there 5 minutes after the second dose, or if symptoms are getting worse, seek emergency medical help immediately.
Important
Do not drive yourself to hospital with possible heart symptoms. Use emergency services or ask someone else to help you get urgent medical care.
When chest pain is an emergency
Seek emergency medical help immediately if chest pain is severe, new or unexplained, happening at rest, not settling quickly, or worse than your usual angina.
Also seek urgent help if chest pain is associated with breathlessness, sweating, fainting, nausea, feeling very unwell, or pain spreading to the arm, jaw, neck, back, or upper abdomen.
It is better to be checked urgently than to wait at home with possible heart symptoms.
Key message
Angina is not the same as a heart attack, but it is an important warning sign.
Stable angina usually follows a pattern and settles with rest or prescribed medicine. Unstable angina is different: it may happen at rest, feel worse, last longer, or fail to settle. That needs emergency medical help.
If your chest pain changes from your usual pattern, take it seriously.
References
- NHS. Angina.
- British Heart Foundation. GTN spray advice.
- American Heart Association. Angina and unstable angina.
- American Heart Association. Prinzmetal angina.