(NewsNation) — When it comes to strokes, every second matters. Fast action can save lives and improve recovery.

According to the National Heart, Lung, and Blood Institute, “a stroke can occur when blood flow to the brain is blocked or there is sudden bleeding in the brain.”

Here’s what you should and shouldn’t do if you suspect someone is having a stroke:

1. Call 911 immediately

At the first sign of stroke symptoms, call 911 and tell the dispatcher you suspect a stroke. If you’re unsure of the signs, use the FAST test:

• Face drooping
• Arm weakness
• Speech difficulty
• Time to call 911

2. Note the time symptoms begin

Treatments such as clot-busting drugs must be given within 24 hours, and the sooner the better.

After calling 911, closely monitor when symptoms started.

If the affected person was found alone, Kelley A. Humbert, MD, assistant professor of Clinical Neurology at Penn Medicine, recommends determining the last time they were seen acting normally.

3. Perform CPR if needed

Most stroke patients don’t need CPR, but if the person is unconscious and not breathing, start CPR immediately after calling 911.

The dispatcher can guide you through chest compressions if needed.

4. Don’t let them sleep it off

Stroke symptoms can cause drowsiness, but do not let them rest or wait to see a doctor later. They need emergency care immediately.

Humbert urges you not to allow the patient to talk you out of taking them to the hospital.

5. Don’t give food, drink or medication

Avoid offering anything by mouth.

Medication, such as aspirin, could hurt the person more. Strokes can impair swallowing, and if it’s a hemorrhagic stroke, blood thinners can worsen the bleeding.

Additionally, don’t give them food or drinks before the ambulance arrives.

6. Don’t drive to the hospital

Always call 911.

Emergency responders can begin treatment en route to the hospital and ensure that the person gets to a stroke-ready hospital.

Driving yourself or someone else could delay critical care.

Types of strokes

There are two types of strokes: ischemic and hemorrhagic.

An ischemic stroke occurs when the blood supply to the brain is blocked or reduced, preventing oxygen, according to the Mayo Clinic.

A hemorrhagic stroke occurs when a blood vessel in the brain leaks, causing bleeding in the brain.

Typically, stroke symptoms include:

• Numbness or weakness in the face, arm or leg, especially on one side of the body.
• Confusion, trouble speaking or difficulty understanding speech.
• Trouble seeing in one or both eyes.
• Difficulty walking, dizziness, loss of balance or lack of coordination.

Doctors can detect a silent stroke through a brain scan and subtle symptoms like forgetfulness or difficulty moving around.

Contributing factors that increase the likelihood of stroke include high blood pressure, heart disease, diabetes and an irregular heartbeat.

NewsNation’s Ashley N. Soriano contributed to this report.