A stroke happens when the blood supply to part of the brain is suddenly reduced or stopped. That part of the brain dies and no longer works.

Blood cannot get to your brain when a blood vessel is blocked or bursts inside the brain. This can happen in different ways:

• A blood clot in an artery blocks blood flow to the brain.
• An artery in the brain tears or bursts. Blood spills out into the brain.

You are more likely to have a stroke if you have high blood pressure, heart disease, diabetes, sleep apnea, sickle cell anemia, or high cholesterol. You are also more likely to have a stroke if you use cocaine, if you smoke, or if you are overweight.