BE FAST is a simple, easy-to-remember public education tool designed to help bystanders quickly recognize the common signs of a stroke. The acronym serves as a direct prompt for identifying neurological symptoms that indicate a medical emergency is occurring. Rapid recognition is the first step toward faster treatment, which can significantly reduce the risk of long-term disability or death associated with a stroke. A stroke, sometimes called a “brain attack,” happens when blood flow to a part of the brain is blocked or a blood vessel ruptures, and immediate action is necessary to preserve brain tissue.
Decoding the Acronym: B, E, F, A, S
The first five letters of the BE FAST acronym represent the most common physical symptoms of a stroke, guiding a person through a quick assessment. The “B” stands for Balance, referring to a sudden loss of coordination or an unexpected onset of dizziness or vertigo. If a person suddenly struggles to walk, stumbles, or cannot maintain a stable posture without support, this points to a potential problem.
The “E” represents Eyes, indicating a sudden change in vision. This symptom can manifest as abrupt blurring, double vision, or the total loss of sight in one or both eyes. Asking the individual if they are experiencing any new visual disturbance is a direct way to check for this sign.
“F” is for Face Drooping, often one of the most recognizable stroke signs. To check for this, ask the person to smile, and observe whether one side of the face appears numb or droops downward. This asymmetry is caused by neurological damage affecting the facial nerves.
“A” stands for Arm Weakness, which involves asking the person to raise both arms in front of them. A positive sign occurs if one arm cannot be lifted fully or if it drifts downward involuntarily, demonstrating sudden weakness or numbness. This unilateral weakness is a strong indicator of a stroke affecting the motor cortex.
The “S” for Speech Difficulty covers several issues, including slurred or garbled speech (dysarthria), or difficulty understanding simple commands (aphasia). Ask the person to repeat a simple sentence, and listen for slurring or confused language. Any sudden difficulty in communicating or comprehending language is a serious neurological symptom.
The Critical Importance of Time
The final letter, “T,” stands for Time, which is the most consequential component of the acronym. Time represents the urgent need to call emergency services immediately upon recognizing any of the prior symptoms. This urgency is based on the medical reality that “time is brain,” highlighting that brain cells die rapidly when blood flow is blocked or disrupted.
For every minute that a large-vessel stroke goes untreated, an estimated 1.9 million neurons are lost, leading to increased risk of permanent disability. The narrow window for administering clot-busting medications, such as intravenous tissue plasminogen activator (tPA), makes speed paramount. This drug is most effective when given within 3 to 4.5 hours of symptom onset for eligible patients with ischemic stroke.
Mechanical thrombectomy, a procedure to physically remove a large blood clot, can sometimes be performed up to 24 hours after onset in select cases, but earlier treatment yields the best outcomes. Delays in receiving this specialized care dramatically reduce the chances of a good recovery. The time factor emphasizes that even if symptoms temporarily disappear, immediate medical evaluation is still necessary.
Immediate Action Steps
If any of the BE FAST symptoms are observed, the first action is to call emergency services. Do not attempt driving the person to the hospital, as paramedics can begin medical care upon arrival and transport the patient to the most appropriate stroke center faster. Alerting emergency personnel initiates a specialized response, ensuring the hospital’s stroke team is ready before the patient arrives.
A crucial piece of information to gather is the exact time the symptoms were first noticed, or the last time they were known to be normal (if they woke up with symptoms). This “last known well” time is used by medical staff to determine eligibility for time-sensitive treatments like tPA. While waiting for help, keep the person calm and safe, perhaps lying on their side with their head slightly elevated.
Do not give the person any food, water, or medication, including aspirin, as a stroke can impair swallowing, risking choking or aspiration. Aspirin is a blood thinner that can worsen outcomes if the stroke is caused by bleeding (hemorrhagic). Supporting the individual and providing the exact symptom onset time are the most helpful actions a bystander can take.