Recognizing a Stroke: The FAST Signs Everyone Should Know
Learn to spot a stroke in seconds with FAST — and exactly what to do while the ambulance is on its way.
To recognize a stroke, use FAST: Face — ask them to smile and look for one side drooping; Arms — ask them to raise both and watch for one drifting down; Speech — ask them to repeat a sentence and listen for slurring; Time — if you see any one sign, call 911 immediately and note when symptoms started. While you wait: keep the person calm and still, give nothing to eat or drink, and be ready to start CPR if they stop breathing normally.
Stroke is one of the leading causes of death and long-term disability in Canada. But here is what most people do not realize: how well someone recovers from a stroke depends enormously on how quickly they get to hospital — and that often comes down to whether a family member, friend, or bystander recognizes the signs and acts.
If you have aging parents, a partner, or older relatives, learning to recognize a stroke is one of the most valuable things you can do for them. The signs are simple to remember, and the response is straightforward. This guide gives you both.
FAST: The Four Signs of a Stroke
The easiest way to recognize a stroke is the FAST check — a recognized stroke assessment scale endorsed by the Heart & Stroke Foundation and the Canadian Red Cross (and recommended for lay rescuers by ILCOR). It takes about 30 seconds and requires no equipment.
FFace — is it drooping?
Ask the person to smile. Look closely: does one side of the face droop, or does the smile look uneven? A drooping cheek, eyelid, or mouth on one side is a classic stroke sign.
AArms — can they raise both?
Ask the person to raise both arms over their head and hold them there. Watch for one arm drifting downward, or being unable to lift one arm at all. Weakness on one side of the body is a key warning sign.
SSpeech — is it slurred or strange?
Ask them to repeat a simple sentence like “The sky is blue today.” Listen for slurred speech, jumbled or wrong words, or an inability to speak or understand you at all.
TTime — call 911 now
If you notice any one of these signs, it is time to call 911 immediately. Tell the dispatcher you suspect a stroke and, crucially, tell them what time the symptoms started (or when the person was last seen well). Time is the single most important factor in stroke treatment.
Source: Heart & Stroke Foundation of Canada (FAST); Canadian Red Cross 2025; ILCOR 2025 first aid consensus (stroke assessment scales for lay rescuers).
Other Stroke Signs Beyond FAST
FAST catches most strokes, but not all. According to the Heart & Stroke Foundation and the Canadian Red Cross, you should call 911 if someone suddenly develops any of these, especially on one side of the body:
- Sudden numbness or weakness of the face, arm, or leg
- Sudden confusion or trouble understanding others
- Sudden trouble seeing in one or both eyes
- Sudden trouble walking, dizziness, loss of balance or coordination
- A sudden, severe headache with no known cause — sometimes described as “the worst headache of my life”
The common thread is the word sudden. Stroke symptoms come on abruptly, often within seconds or minutes.
Source: Heart & Stroke Foundation of Canada; Canadian Red Cross 2025 (signs and symptoms of stroke).
What to Do While You Wait for the Ambulance
Once you have called 911, there are simple, important things you can do — and some things you must avoid.
1Note the exact time symptoms began
This is critical. Clot-dissolving and clot-removal treatments have strict time windows. If you did not see it start, work out when the person was last definitely well (for example, “they were fine at dinner at 6:30”). Write it down so you do not forget under stress.
2Keep the person calm, comfortable, and still
Help them sit or lie down with their head and shoulders slightly raised and supported. Loosen any tight clothing. Reassure them — stroke can be frightening and confusing, and a calm voice helps.
3Do not give them anything to eat or drink
A stroke can impair the ability to swallow, so food, water, or pills can go into the lungs and cause choking. Do not give aspirin or any other medication unless a 911 dispatcher specifically instructs you to.
4If they are unconscious but breathing, use the recovery position
Roll them gently onto their side with the head tilted back slightly so the airway stays clear and any saliva or vomit can drain. Keep monitoring their breathing.
5Be ready to start CPR
If the person stops breathing or breathes abnormally (gasping) and is unresponsive, begin CPR right away and continue until paramedics arrive. If you are unsure how, the 911 dispatcher can talk you through it — but having taken a CPR course means you will not freeze.
6Gather useful information for paramedics
If you can do it without leaving the person, collect their medication list and note any known conditions like diabetes, high blood pressure, or atrial fibrillation. This helps the hospital team act quickly.
Why “Time Is Brain”
During most strokes, a blood clot blocks an artery, cutting off oxygen to part of the brain. Brain cells in that area begin dying almost immediately — clinicians say the brain “dies by the minute” — and they do not grow back (Canadian Red Cross 2025). The longer the blockage lasts, the more permanent damage occurs — affecting movement, speech, memory, and independence.
Modern stroke treatments can dissolve or physically remove the clot and restore blood flow, but they work best when given quickly, and most have time limits measured in hours from symptom onset (ILCOR 2025). A person who arrives at hospital sooner has a dramatically better chance of recovering well than one who waits. That is why recognizing the signs and calling 911 immediately matters so much.
Source: Canadian Red Cross 2025; ILCOR 2025 first aid consensus. The often-quoted “two million brain cells per minute” figure comes from a single 2006 estimate (Saver) and is not used in current Canadian first aid guidance, so we describe the loss qualitatively.
Mini-Strokes: Don’t Be Reassured When Symptoms Pass
Sometimes stroke symptoms last only a few minutes and then vanish completely. This is often a transient ischemic attack (TIA), or “mini-stroke.” It is tempting to feel relieved and move on — but a TIA is a serious warning that a full stroke may be coming, sometimes within hours or days.
Be the Person Who Knows What to Do
Recognizing a stroke is something everyone in a family should be able to do — but the response often involves more than FAST. Positioning an unconscious person, keeping an airway clear, and starting CPR are hands-on skills best learned by doing. A Life Safe first aid and CPR course covers stroke recognition alongside the practical skills that keep someone alive until paramedics arrive — invaluable for anyone caring for older parents or relatives.
Frequently Asked Questions
What does FAST stand for in stroke?
Face, Arms, Speech, Time. Face: ask them to smile and look for drooping on one side. Arms: ask them to raise both and watch for one drifting down. Speech: ask them to repeat a sentence and listen for slurring. Time: if you see any one sign, call 911 immediately and note when symptoms started. FAST is a recognized stroke scale used by the Heart & Stroke Foundation and Canadian Red Cross.
What should I do while waiting for an ambulance?
Call 911 and note the exact time symptoms began. Keep the person calm and still, sitting or lying with the head slightly raised. Do not give food, drink, or medication, as a stroke can affect swallowing. Monitor their breathing and be ready to start CPR if they become unresponsive.
Why does time matter so much in a stroke?
Brain cells die by the minute during a stroke — “time is brain.” Clot-busting and clot-removal treatments work far better the sooner they are given, with strict time windows measured in hours. The faster someone reaches hospital, the more brain is saved and the better the recovery.
Should I drive someone to the hospital myself?
No — always call 911. Paramedics can begin assessment on the way, alert the hospital so a stroke team is ready, and take the person to a hospital equipped to treat strokes. Driving yourself wastes critical time and risks a crash if they deteriorate.
Can stroke symptoms go away on their own?
Sometimes symptoms last only minutes then disappear — this can be a mini-stroke (TIA), a serious warning that a major stroke may follow within days. Never ignore symptoms because they pass. Call 911 even if the person recovers, as they need urgent assessment.
Can low blood sugar look like a stroke?
Yes — low blood sugar (hypoglycemia) is a classic stroke mimic that can cause one-sided weakness, confusion, and slurred speech (ILCOR). It is why paramedics check blood glucose. It does not change your response: still call 911. If the person has diabetes, is fully awake, and can swallow safely, a dispatcher may guide you on giving sugar — never force food or drink on someone drowsy or unable to swallow.
Could You Recognize a Stroke in Someone You Love?
FAST is simple — but the calm, hands-on response that follows takes training. Life Safe’s first aid and CPR courses prepare you to recognize medical emergencies and act decisively, whether it is a parent, a partner, or a stranger who needs you.
Find a class near you: Toronto • Downtown Toronto • East York • Hamilton • Welland • Guelph
Sources & medical review
Reviewed by Milos Radojcic (Canadian Red Cross / Heart & Stroke / Lifesaving Society First Aid & CPR Instructor, 10+ yrs). Clinical content aligned with the Heart & Stroke Foundation of Canada, the Canadian Red Cross (2025), and the 2025 ILCOR first aid consensus on stroke assessment scales (FAST, Cincinnati, and glucose-inclusive scales). Last reviewed July 2026.