Neurology

Recognizing a Stroke FAST — A Practical Guide

How to use the FAST test and other warning signs to act quickly and reduce brain damage.

Updated: 6 min read

Intro

A stroke occurs when blood supply to part of the brain is cut off — either by a clot blocking an artery (ischaemic stroke, approximately 85% of cases) or by a blood vessel rupturing (haemorrhagic stroke). Brain cells begin dying within minutes of losing their blood supply. Unlike most other organs, the brain has almost no ability to compensate for or recover cells that have been destroyed.

Time is the most critical factor in stroke treatment. For every minute without treatment, approximately 1.9 million neurons die. The faster a stroke is recognised and treated, the greater the chance of survival with minimal disability. Knowing the FAST signs — and acting on them without hesitation — is one of the most important emergency skills anyone can have.

Key Points

  • Use the FAST test: Face drooping, Arm weakness, Speech difficulty, Time to call emergency services.
  • Even one FAST sign alone is reason to call emergency services immediately.
  • Stroke treatment is strictly time-sensitive — clot-dissolving medication must be given within 4.5 hours of symptom onset.
  • A TIA (“mini-stroke”) with symptoms that resolve is still a medical emergency — the risk of a full stroke in the following days is very high.
  • Do not give aspirin unless instructed by emergency services — haemorrhagic strokes are worsened by aspirin.
  • Do not drive the person to hospital — call an ambulance so treatment can begin en route.
  • Note the exact time symptoms started — this determines which treatments can be offered.

When to Get Emergency Help

Call emergency services immediately if you or someone nearby has any of the following:

  • Face drooping — one side of the face droops, feels numb, or produces an uneven smile
  • Arm weakness — one arm is weak or numb; when both arms are raised, one drifts downward involuntarily
  • Speech difficulty — speech is slurred, the person cannot speak, or they cannot understand simple instructions
  • Sudden severe headache — described as the worst headache of their life, coming on suddenly with no apparent cause
  • Sudden vision loss — blurred, double, or complete loss of vision in one or both eyes
  • Sudden confusion or disorientation — difficulty understanding surroundings or following a conversation
  • Sudden dizziness or severe loss of balance — especially when combined with any other stroke sign
  • Sudden numbness or weakness on one side of the face, arm, or leg

Do not drive the person to hospital. Call an ambulance. Paramedics can begin assessment, administer oxygen, and alert the hospital to prepare — all before arrival.

Common Causes

Strokes are caused by disrupted blood flow to the brain:

Ischaemic stroke (clot): A blood clot blocks an artery supplying the brain. Often linked to atrial fibrillation (irregular heart rhythm), carotid artery disease, or clots that travel from the heart. This is the most common type and is potentially reversible if treated quickly.

Haemorrhagic stroke (bleed): A blood vessel bursts inside or around the brain. Often linked to high blood pressure, arterial malformations, or anticoagulant medication. Aspirin and thrombolysis are harmful in this type — which is why a brain scan is essential before any treatment.

TIA (transient ischaemic attack): A temporary blockage that resolves on its own, usually within minutes. Symptoms clear completely, but the short-term stroke risk is high. Treat every TIA as an emergency — this is not a “mild” or “warning” stroke to wait out at home.

Key risk factors include high blood pressure, atrial fibrillation, smoking, diabetes, high cholesterol, obesity, physical inactivity, and prior TIA or stroke.

What to Do Right Now

  1. Apply the FAST test — Face, Arm, Speech. If any one sign is present, proceed immediately to step 2.
  2. Call emergency services — give your location and describe the symptoms clearly. State the time symptoms began, or the last time the person was seen acting normally.
  3. Do not give aspirin — wait for explicit instructions from emergency services.
  4. Keep the person calm and still — have them sit or lie down safely. If they are unconscious but breathing, place them in the recovery position.
  5. Do not give food or drink — stroke can impair swallowing and cause choking.
  6. Stay with them until paramedics arrive and continue monitoring their breathing and consciousness.
  7. If they become unresponsive and stop breathing normally, begin CPR if you are trained.

FAQ

What does FAST stand for? Face drooping, Arm weakness, Speech difficulty, Time to call emergency services. Any one of these signs alone is reason to call for help immediately — do not wait for all three.

Can stroke symptoms go away on their own? Yes — a TIA causes symptoms that resolve within minutes to hours. But a TIA is still a medical emergency. The risk of a full stroke is highest in the 24 to 48 hours after a TIA. Seek urgent evaluation even if you feel completely better.

Should I give aspirin? No — not before a brain scan. Some strokes involve bleeding, and aspirin worsens haemorrhage. Only give aspirin if directed by emergency services or a doctor.

What is the treatment window? Clot-dissolving medication (thrombolysis) must be given within 4.5 hours of symptom onset. Mechanical clot removal (thrombectomy) may be possible up to 24 hours in selected cases. Every minute saved means more brain cells preserved.

What happens after a TIA? You will typically be assessed within 24 hours, given medication to reduce clot formation, investigated for underlying causes such as atrial fibrillation, and possibly prescribed long-term preventive therapy. Never wait for symptoms to recur before seeking help.

Can a stroke cause a severe headache? A sudden, violent thunderclap headache — often described as the worst headache of a person’s life — can signal a subarachnoid haemorrhage (bleeding around the brain). This is a life-threatening emergency requiring immediate evaluation.

Is arm or face weakness always present? No. Sudden confusion, vision loss, severe headache, or loss of coordination alone can each indicate a stroke. Never dismiss the possibility of stroke just because the “classic” FAST signs are not all present.

What should I tell emergency services? Give your location, describe the symptoms in detail, and state the exact time they began. If you found the person unwell, state when they were last seen acting normally. This directly affects which treatments can be offered.

Further Reading