Stroke, also known as a brain attack, occurs when blood flow to the brain is disrupted. Stroke is the third leading cause of death in the U.S.The brain needs a constant supply of oxygen and nutrients to function properly. Even a brief interruption in blood supply can cause significant problems. Brain cells begin to die after just a few minutes without blood or oxygen. Due to both the physical and chemical changes that occur in the brain with stroke, damage can continue to occur for several days. How Stroke Impairs Your Health Stroke may cause impairments in movement, speech, thinking and memory, bowel and bladder control, eating, emotional control, and other vital body functions. Recovery from stroke and the specific ability affected depends on the size and location of the stroke. A small stroke may result in only minor problems such as weakness in an arm or leg. Larger strokes may cause paralysis, loss of speech, or even death. Types Strokes can be classified into two main categories: Ischemic: about 87 percent of cases Hemorrhagic: about 13 percent of cases An ischemic stroke occurs when a blood vessel that supplies the brain becomes blocked and impairs blood flow to part of the brain. The starving brain cells and tissues begin to die within minutes. Hemorrhagic strokes occur when a blood vessel that supplies the brain ruptures and bleeds. When an artery bleeds into the brain, brain cells and tissues do not receive adequate oxygen and nutrients. In addition, fluid pressure builds up in surrounding tissues and irritation and swelling occur. Risk Factors Evaluating your risk for stroke is based on heredity, natural processes, and lifestyle. Risk factors that you can change, treat, or medically manage include the following: high blood pressure, diabetes, heart disease, cigarette smoking, history of transient ischemic attacks (TIAs) or ministrokes, high blood cholesterol and lipids, physical inactivity, obesity, alcohol and drug abuse, and abnormal heart rhythm. Risk factors for stroke that you cannot change include: Age: for each decade of life after age 55, the chance of having a stroke more than doubles Gender: men have about a 19 percent greater chance of stroke than women Race: African-Americans have a much higher risk of death and disability from a stroke than Caucasians Personal history of prior stroke Family history of stroke When to Call 911 If you think you are suffering a stroke, call 911 immediately. Stroke is an emergency. The greatest chance for recovery occurs when emergency treatment is started immediately. Emergency treatment may include medications that dissolve blood clots, reduce or control brain swelling, or help protect the brain from damage and ischemia (lack of oxygen). Several types of surgery may also be performed to help treat a stroke or to prevent a stroke from occurring.