A stroke results from interrupted or reduced blood flow to the brain, which may be caused by leaking or bursting blood vessels or a blocked artery, according to Mayo Clinic. Patients may also experience a less severe form of stroke if debris or a blood clot temporarily restricts blood flow.
An ischemic stroke is the most common form of stroke, accounting for around 85 percent of cases, and it is often caused by a clot of fatty deposits that sometimes form in an artery that carries blood to the cerebral area, as Mayo Clinic explains. The clot may also form in the heart and be carried into the smaller arteries leading to the brain. A hemorrhagic stroke occurs when a blood vessel bursts and leaks into the cavity between the brain and skull or into surrounding brain tissue.
People who drink excessively, are overweight, use illicit drugs or do not exercise regularly have a greater risk of experiencing a stroke, according to Mayo Clinic. Other risk factors include high blood pressure, diabetes, high cholesterol, smoking and cardiovascular disease. A family history of stroke and being over the age of 55 also correlate with a heightened risk of stroke, as Mayo Clinic indicates. However, up to 80 percent of strokes can be prevented, according to the National Stroke Association.