A stroke occurs when a blood clot blocks an artery or vessel in the brain, interrupting blood flow and oxygen. There are two main types of strokes: ischemic, caused by a blocked artery, and hemorrhagic, caused by a ruptured blood vessel. Signs of a stroke include facial drooping, arm weakness, speech difficulties, and time to call for help. Symptoms include headache, nausea, numbness, weakness, and paralysis. If someone is having a stroke, call an ambulance immediately and follow first aid procedures until help arrives. Lifestyle changes like managing health conditions, diet, exercise, and avoiding smoking can help prevent strokes.