Stroke is the leading cause of death and a major cause of disability in adults in the U.S. Stroke takes the lives of approximately 130,000 Americans each year and on average, one American dies from stroke every four minutes. These are startling statistics, but by acting F.A.S.T. at the first sign of stroke, you can greatly increase your or someone else’s chance of survival.

We spoke with emergency medicine doctor Peter Paganussi, MD, of our own StoneSprings Hospital Center in Dulles, Virginia to learn what to do if a loved one, or even yourself, is having a stroke.

Stroke Basics

“A stroke occurs when a portion of the brain is deprived of oxygen or blood. That piece of the brain either dies or significantly malfunctions as a result,” explains Dr. Paganussi. There are two major types of stroke. Roughly 85-87% of strokes are ischemic, commonly referred to as dry strokes, while 15 to 20% are hemorrhagic. The difference between the two being that in ischemic strokes, a blood clot is present in one of the arteries supplying blood to an area of the brain, whereas in hemorrhagic strokes, a rupture in an artery in the brain occurs. “In both instances, a portion of brain tissue is damaged by a lack of oxygen and blood flow, and that creates a stroke,” says Paganussi.

Stroke Warning Signs

When it comes to stroke, every minute counts. The sooner you get treated, the better your chance of survival and recovery.

“We, as physicians, like to give the medication within four hours of [stroke] onset, because we know it works better and the outcomes are better,” says Paganussi. “We really try to give it in under two, if we can.”

If someone is having a stroke, think and act F.A.S.T:

  • F-Face: Watch for facial drooping. Ask the person to smile and see if one side of the face droops.
  • A-Arms: : Is one of their arms weak? Ask them to raise both arms, laterally or medially. Does one arm drift downward?
  • S-Speech: Look out for slurred speech. Ask them to repeat a simple phrase, such as: “The sky is blue.” Can he or she do it?
  • T-Time: If you notice any of these symptoms, call 9-1-1 immediately. Even if the symptoms go away, still call for help.

Companies and organizations training first responders, including Ellis & Associates and the Red Cross, to the highest skilled doctors are taught to look for signs and symptoms of stroke by using the F.A.S.T. acronym. Remember to think F.A.S.T. when needed.

“Sometimes, severe headaches or vertigo (dizziness) can accompany a stroke but these symptoms aren’t typical,” says Paganussi. “However, a sudden change of vision associated with weakness, may signal a stroke,” he says.

Be sure to note the time that symptoms first appeared. And don’t try to drive yourself or a loved one to a hospital. Call for an ambulance so treatment can begin immediately.

This content originally appeared on Sharecare.com.