Nearly 140,000 Americans die each year due to stroke, which is among the top five causes of death in the country. It is also the leading cause of disability, reducing mobility in many survivors who are over the age of 65. Commonly referred to as a brain attack, it occurs when blood and oxygen are unable to reach the brain. This can have immediate effects depending on the part of the brain affected. 

According to the Stroke Association, there are two main types of strokes. An ischaemic stroke is defined as "a blockage cutting off the blood supply to the brain," while a stroke "caused by a bleeding in or around the brain" is referred to as a hemorrhagic stroke.

Ischemic stroke is the more prevalent of the two, making up around 87% of all stroke cases. It occurs due to the hardened, build-up of fatty substances in the arteries which can lead to a breakaway piece of plaque i.e. a blood clot. Typically, the clot will lodge itself in the artery connecting to the brain, preventing the essential flow of blood.

On the other hand, during the less common hemorrhagic stroke, the blood vessel itself bursts. The vessels may be located inside the brain or on the surface of the brain. The rupture can cause swelling and bleeding around the skull as well as damage to the surrounding cells and tissues.

Once a stroke occurs, the person will display one or more noticeable signs such as unusually slurred speech. Another major sign is numbness and weakness on one side of the face and body. For example, one of the eyes or one side of the mouth may droop. The person may also be unable to move the arm or leg on one side of the body. Other symptoms include sudden confusion, blurred vision, loss of balance, lack of coordination, and severe headaches.

"The hardest thing you have to do is recognize symptoms of a stroke," says Jean D. Luciano, CRNP, Stroke Team Co-Director of the Comprehensive Stroke Center at Penn Medicine and a nurse practitioner at the Penn Medicine Neuroscience Center. "If you do observe any symptoms, you should call 911 immediately," she says, emphasizing that treatment is extremely time-sensitive so people must react quickly.

The National Institutes of Health (NIH) lists numerous risk factors for stroke such as high blood pressure, diabetes, and heart disease. Alcohol use, cocaine use, lack of physical activity, smoking, and unhealthy diets are considered some of the more controllable factors. Those with relatives who have experienced stroke are also at high risk.

Based on age, gender and race, some groups are more likely to experience a stroke. "Your risk of stroke increases as you get older. At younger ages, men are more likely than women to have strokes. However, women are more likely to die from strokes," the NIH states. They also occur more often in African American, Alaska Native, and American Indian adults compared to white, Hispanic, or Asian American adults.