Getting prompt treatment after a stroke could save your life. Learn the signs here.

Fifteen minutes can save the life of someone who’s suffered a stroke. Doctors have long-known that acting fast is crucial, but a new study from the University of California, Los Angeles found that getting stroke treatment just 15 minutes faster can prevent disability and death.

The research, published in JAMA, looked at the “door-to-puncture” time for nearly 7,000 people who’d had ischemic strokes—that’s doctor-speak for the time they entered the hospital to when interventional treatment began. In this case, the treatment was endovascular reperfusion therapy, which is used to treat strokes caused by blockages in major brain arteries. The “puncture” is the one doctors make to the artery to start treating the blockage.

The researchers found that each 15 minute improvement in door-to puncture time, there were 15 out of 1000 fewer deaths or hospice discourages. Also, 17 out of 1000 were able to walk out of the hospital unassisted, and 22 of 1000 could take care of themselves after being discharged.

The average time from arriving at the hospital to the start of treatment was just under an hour and necessary time to perform diagnostic tests such as CT scans of the brain. For example, treatment was most delayed when patients arrived during hospital “off hours,” like the middle of the night, weekends, or holidays. The best treatment outcomes occurred in hospitals where the staff treated more than 450 stroke patients per year.

Nearly 800,000 people have strokes per year in the United States, and about 140,000 of them end up losing their lives, says the Centers for Disease Control and Prevention. But the JAMA study’s authors found that speeding up care even a little bit could save thousands of them.

Know the Signs of Stroke

While the American Heart Association (AHA) has already looked at this study’s results and published new goals about how fast stroke patients need to be treated, there’s another key factor to success: you. It’s vital for everyone to know the signs of a stroke. That way, should you or someone else experience them, you can take immediate action and get to the hospital ASAP for care.

The AHA offers this handy acronym, “FAST,” to help you remember the key signs of a stroke:

• F is for face drooping. If you think someone is having a stroke, ask them to try to smile. If one side of their face droops or is numb, that’s a common sign of stroke.
• A is for arm weakness. If one arm is weak or numb, that can be another sign. Ask the person to raise both of their arms—if one drifts downward, a stroke is possible.
• S is speech difficult. Ask the person to repeat a simple sentence (like “the sky is blue”) and see if they can say it correctly. If the person’s speech is slurred or they can’t speak clearly—or at all—that’s another potential sign.
• T is for time to call 9-1-1. If the person shows any of these symptoms—even if they improve over time—call 9-1-1 and head to the hospital quickly for care.