All types of strokes involve the interruption of blood supply to some area of a persons brain. Both blocked and leaking blood vessels result in a lack of oxygen and nutrients to brain cells. It takes only a few minutes after blood flow is interrupted to kill millions of brain cells. 

Types of Strokes and Causes

Thrombotic Stroke

This type of stroke usually happen when blood vessels have atherosclerosis (build-up of cholesterol and other fats, combined with calcium). This leads to plaques” along the vessels’ walls.

Atherosclerosis causes blood clots that can suddenly block already narrow arteries. Sometimes the clots happen in the carotid arteries of the neck. This stops the blood from getting to a persons brain.

Embolic strokes

These strokes often happen with an abnormal heart rhythm in one of the upper chambers of the heart (called an atrium). This abnormal heart rhythm is atrial fibrillation. It may cause blood clots to form in the heart, which may travel up to the brain and cause an embolic stroke.  

Intracerebral hemorrhagic strokes

This type of stroke is usually caused by uncontrolled high blood pressure (hypertension).

Subarachnoid hemorrhagic strokes

These strokes likely happen due to the breaking of a weak area of a blood vessel known as an aneurysm. Often, people are born with these weak areas.

Lifestyle Factors

A person with an unhealthy lifestyle is more likely to have a stroke. Risk increases with:

  • Obesity or being overweight
  • A diet high in bad fats (saturated and trans fats) and low in good” fats like those found in plants.
  • High salt intake
  • Alcohol, smoking, and substance misuse.
  • Substances include cocaine and other illegal drugs.

Medical Factors

Having certain diseases increases a persons chances of having a stroke. They include: 

  • Previous stroke and family history of stroke
  • High blood pressure (hypertension); this is the number one risk factor for stroke. And high cholesterol
  • Heart disease, including atrial fibrillation
  • Diabetes
  • Old age and being a person of color
  • Atherosclerosis and peripheral artery disease (PAD). PAD happens when the plaques are in blood vessels that carry blood to different parts of the body. These parts include the legs and the neck. This can lead to reduced blood flow to these body parts.
  • Other problems that are not well-controlled, such as anemia and sickle cell anemia


Last Updated March 2023

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