On average, someone in the U.S. has a stroke every 40 seconds. A stroke occurs when the blood supply to part of the brain is interrupted, depriving the brain of oxygen. It's important to recognize the warning signs of stroke, because prompt treatment can minimize brain damage. Every moment is crucial.

"Strokes commonly occur in people of all ages," says Dr. Robert Brown, Jr., chair of Mayo Clinic's Division of Stroke and Cerebrovascular Diseases. "And, so, it's very important that people know what is a stroke, what are the symptoms and what are the risk factors for stroke?"

May is National stroke Awareness Month. In this Mayo Clinic Q&A podcast, Dr. Brown explains the importance of remembering the F.A.S.T. acronym to recognize a stroke: face drooping, arm weakness, speech difficulty, time to call 911.