What Is a Stroke? Symptoms, Causes, Diagnosis, Treatment, and Prevention
Updated on November 25, 2025
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A stroke occurs when the flow of blood to the brain is blocked. It is a medical emergency because blood carries oxygen, and brain cells can die within minutes without it.
While strokes can occur at any age, your risk increases as you get older. Not every stroke can be prevented, but there are many steps you can take to reduce your risk.
It’s important to recognize the signs of a stroke and to call 911 for emergency medical attention if you think someone is having one. Getting treatment quickly may prevent death or disability.
Stroke Signs and Symptoms
Knowing the signs and symptoms of a stroke can help save lives. The type and severity of stroke symptoms depend on the area of the brain that is affected. Signs and symptoms of a stroke can vary between men and women and may include:
- Sudden numbness, weakness, or inability to move the face, arm, or leg (especially on one side of the body)
- Confusion
- Trouble speaking or understanding speech
- Trouble seeing in one or both eyes
- Dizziness, trouble walking, or loss of balance or coordination
- Sudden severe headache
The acronym FAST can help you remember the signs and symptoms of stroke.
- Face Drooping Ask the person to smile. Is the smile uneven?
- Arm Weakness Ask the person to raise both arms. Does one drift downward?
- Speech Difficulty Is speech slurred or hard to understand? Ask the person to repeat a simple sentence, such as “The sky is blue.” Is the sentence repeated correctly?
- Time to Call 911 If someone shows any of these symptoms — even if the symptoms go away — call 911. Check the time so you can tell responders when the symptoms first started.
People who experience a stroke have the best chance of survival and may have less disability if someone around them recognizes the signs and acts quickly by calling 911.
Causes and Risk Factors of Stroke
There are two main types of stroke, each with different causes:
- Ischemic strokes are caused by blood clots.
- Hemorrhagic strokes are caused by bleeding in or around the brain.
Ischemic strokes account for about 87 percent of all strokes. They happen when there’s a blood clot that blocks blood flow to a part of the brain. There are two ways this can happen:
- A clot can form in a blood vessel of the neck or brain that has been narrowed by a buildup of plaque. Plaque is a combination of fat, cholesterol, and other substances that accumulate in the inner lining of the artery walls. Plaque buildup is known as atherosclerosis, or “hardening of the arteries.”
- A clot can arise from the heart or break off from a blood vessel elsewhere in the body and travel to the brain, where it becomes stuck in one of the brain’s tiny blood vessels. This is called embolism.
A hemorrhagic stroke occurs when a weakened blood vessel in the brain ruptures and bleeds into surrounding brain tissue. This puts too much pressure on blood cells in the surrounding tissue, cutting off their blood supply and causing damage. About 13 percent of all strokes are hemorrhagic strokes.
An aneurysm — a weak spot in a blood vessel wall that balloons outward — can lead to a hemorrhagic stroke, as can a tangle of malformed blood vessels called an arteriovenous malformation.
Several factors may increase your risk of having a stroke. General stroke risk factors include:
- Older age (especially 55 or older)
- Being Black or Hispanic
- Being a man
- Lack of physical activity
- Heavy alcohol consumption
- Smoking or exposure to secondhand smoke
- Use of recreational stimulant drugs (such as cocaine or amphetamines)
- Being overweight or obese
- High blood pressure
- High cholesterol
- Diabetes
- Sleep apnea
- Cardiovascular disease
- COVID-19
- Personal or family history of stroke or heart attack
There are also specific risk factors for a hemorrhagic stroke:
- Uncontrolled high blood pressure
- Excessive use of anticoagulant drugs (blood thinners)
- Trauma (such as an accident or fall)
- Cerebral amyloid angiopathy (protein deposits in blood vessel walls)
- Ischemic stroke (having had one can lead to hemorrhagic stroke)
How Is a Stroke Diagnosed?
Your emergency medical team will diagnose a stroke based on several factors, including your symptoms, medical history, a physical exam, and diagnostic tests. The following brain and heart tests may be used to help diagnose a stroke.
- Computed Tomography (CT) Scan A brain CT scan uses X-rays to create images of your brain.
- Magnetic Resonance Imaging (MRI) A brain MRI uses magnets and radio waves to create images of your brain.
- Carotid Ultrasound or Carotid Angiography These show the insides of the arteries that supply blood to the brain.
- Echocardiogram This test uses sound waves to create images of your heart and may detect the source of blood clots that have traveled from your heart to your brain.
A brain CT scan or MRI may be used to identify whether your stroke is ischemic (caused by clotting) or hemorrhagic (caused by bleeding), which is essential to treating your stroke. Blood tests may also be helpful to identify a stroke, such as by checking how quickly your blood clots.
Prognosis of Stroke
Stroke can lead to outcomes ranging from a full recovery (without any lasting disability) to death. After emergency treatment and monitoring, your stroke care will be focused on helping you recover as much function as possible.
If you experience ongoing disability because of your stroke, the functions that are affected may depend on the side of your brain where your stroke occurred. A stroke on the right side of your brain tends to affect movement and sensation on the left side of your body. A stroke on the left side of your brain tends to affect the right side of your body and may also affect speech and language.
Most people who have a stroke will enter a rehabilitation program, which may begin before they leave the hospital. Your program will take into account your overall health, degree of disability from stroke, recovery and lifestyle priorities, and support system.
Duration of a Stroke
When you have a stroke, brain cells in the affected area begin to die within minutes of losing oxygen. Many treatment options are most effective when given as soon as possible after a stroke begins. That’s why it’s important to seek emergency medical attention immediately and to note when a person’s stroke symptoms began.
There is no standard duration for a stroke; it depends on the type of stroke. Without treatment, blood flow to your brain may be blocked for a variable period of time, perhaps indefinitely.
Treatment and Medication Options for Stroke
Treatments for stroke depend on the type of stroke. The main treatment for an ischemic stroke is alteplase, or tPA, a thrombolytic medication (clot buster). It can quickly break up or dissolve blood clots that are blocking blood flow to the brain. This drug must be started within a few hours after stroke symptoms first appear.
For an ischemic stroke, doctors may also perform an endovascular catheter-based procedure in which a long, narrow tube is pushed through a blood vessel into your brain to remove a large blood clot.
Treatments for a hemorrhagic stroke include controlling blood pressure and stopping any medications that could increase bleeding, including warfarin and aspirin. You may also receive a blood transfusion with blood-clotting factors to stop ongoing bleeding.
Additionally, a hemorrhagic stroke may require an endovascular procedure (accessed through a blood vessel) or surgery to help stop and prevent further bleeding.
Prevention of Stroke
Management of lifestyle-based risk factors may help prevent a stroke. Additionally, if you are at high risk for an ischemic stroke, you may be prescribed certain medications to reduce your risk. Lifestyle-based stroke prevention measures include the following:
- Eating lots of fruits and vegetables
- Reducing saturated fat in your diet
- Not using tobacco or smoking
- Drinking alcohol in moderation (or not at all)
- Maintaining a healthy weight
- Getting enough exercise
- Controlling blood pressure
- Managing diabetes
- Treating sleep apnea
If you have already had a transient ischemic attack (TIA), also known as a ministroke, or ischemic stroke, your doctor may recommend certain drugs to reduce your stroke risk, such as:
Antiplatelet Drugs These medications make your blood less “sticky” and include aspirin, dipyridamole, and clopidogrel (Plavix).
Anticoagulants These medications reduce blood clotting and include heparin and warfarin along with newer drugs like dabigatran (Pradaxa), rivaroxaban (Xarelto), apixaban (Eliquis), and edoxaban (Savaysa).
Complications of Stroke
A stroke may cause temporary or permanent disabilities. Stroke complications will depend on which part of the brain was affected by the stroke and how long that area of the brain was deprived of oxygen.
Common stroke complications include:
- Paralysis or loss of muscle movement
- Memory loss or cognitive difficulty
- Trouble with talking or swallowing
- Pain or numbness
- Emotional difficulty or loss of motivation
Over time, most people who have a stroke will recover some of the function they have lost. Stroke rehabilitation programs can help, although these programs will not “cure” or reverse brain damage caused by a stroke. Instead, the goal of stroke rehabilitation is to help stroke survivors live as independently as possible while adjusting to new limitations.
Stroke survivors may require:
- Speech therapy
- Physical therapy and strength training
- Occupational therapy (relearning skills required for daily living)
- Psychological counseling or therapy
Some common types of stroke programs and facilities include:
- Inpatient rehabilitation or nursing facilities that provide 24-hour care
- Outpatient facilities, where you may spend several hours a day doing rehabilitation activities
- Home-based programs, in which therapists come to you
Find a Doctor
After receiving emergency treatment for a stroke, hospital staff may refer you to a specialist to follow up on treatment and recovery plans. This will often be a vascular neurologist (stroke doctor), who can prescribe blood thinners or other interventional medications and a rehabilitation plan.
Depending on the severity of your stroke and complications, your neurologist may prescribe an entire medical team — physical, occupational, and psychiatric therapists — for rehabilitation. Be sure to double-check that this team specializes in your stroke rehab needs.
Aphasia After Stroke
Aphasia is a condition characterized by the sudden loss of the ability to communicate and is a common complication of a stroke. More than 2 million people in the United States have aphasia, commonly as a result of stroke.
There are several types of aphasia. Symptoms may include:
- Speaking in short or incomplete sentences
- Speaking in ways that do not make any sense or saying unrecognizable words
- Substituting one word or sound for another
- Not understanding what other people are saying
- Writing words or sentences that do not make any sense
Insomnia After Stroke
Sleep is important for general health and well-being as well as for learning. For stroke survivors trying to relearn basic skills, adequate rest is even more important — it’s a key part of the stroke recovery process.
But good sleep can often be elusive for people who’ve had a stroke. Studies show that insomnia may be a long-term side effect for survivors of stroke, indicating that treating insomnia may be an important part of post-stroke rehabilitation.
This research shows the importance of including treatment of sleep disorders like insomnia in stroke rehabilitation practices.
Neuropathy After Stroke
A stroke can damage your brain, potentially causing a type of neuropathy called central neuropathy. With this form of neuropathy, you may experience burning, sensory hypersensitivity, or prickling sensations in your face, arm, leg, or even half of your body.
This form of post-stroke pain tends to be ongoing and typically develops soon after a stroke, but it can also start later on. About 10 percent of stroke survivors experience central pain or neuropathy.
Research and Statistics: How Common Are Strokes?
Every year more than 795,000 people in the United States have a stroke. About 610,000 of these are first-time strokes. In the States, someone has a stroke every 40 seconds, and someone dies of a stroke every four minutes, on average.
Stroke is the fifth leading overall cause of death. More than half of all stroke survivors age 65 and older will have long-term mobility impairment. While older people are at higher risk for stroke, about 38 percent hospitalized for stroke are younger than 65.
BIPOC and Stroke
Several studies have looked at differences in stroke risk among specific racial and ethnic populations, including Black, Indigenous, and People of Color (BIPOC) communities.
Black Americans are about twice as likely to have a first stroke as white Americans. Black people also have the highest rate of death due to stroke in the United States.
While the death rate from stroke has been dropping for decades in all racial and ethnic groups, for reasons that aren’t clear, Hispanic Americans have seen an increase in this death rate since 2013.
In one study, researchers found that in a group of more than 3,000 older people in New York City, the risk of stroke was highest in Black participants, at 13 per 1,000 person-years (a way to measure incidence rates that shows how often something will happen if, for example, 100 people were followed for 10 years). This was followed by Hispanic participants, at 10, and white participants, at 9. When researchers looked just at those over age 85, Hispanic people had the highest incidence of stroke.
When the researchers controlled for demographic factors that may affect stroke risk, the gap was even greater between white and Black participants, with Black people experiencing a 51 percent higher risk.
Hospital readmission rates after a stroke appear to be similar for different racial and ethnic groups. Of more than 98,000 ischemic stroke survivors, the 30-day readmission rate was 12.7 percent for Black survivors and 10 percent for white survivors.
Conditions Related to Stroke
A transient ischemic attack (TIA), the event known as a ministroke, can be the result of a temporary blockage caused by a blood clot in the brain. It lasts for a few minutes and doesn’t cause any permanent damage.
A TIA can be a warning sign of a future stroke. As many as 10 to 15 percent of people who experience a TIA will have a major stroke within the next three months, according to the Centers for Disease Control and Prevention (CDC). Like a major stroke, a TIA is a medical emergency. It’s not possible to know if you’re having a TIA or a major stroke.
More than a third of people who have a TIA will have a major stroke within a year if they don’t receive treatment.
Ischemic strokes are caused by blood clots that form in or travel to the blood vessels that supply your brain with oxygen and nutrients. Clots can also block blood flow to other areas of your body, causing the following conditions:
- Heart attack
- Pulmonary embolism (affects the lungs)
- Deep vein thrombosis (often affects arms or legs)
The Takeaway
- Stroke is a common condition caused by either a blood clot or a brain bleed. Depending on where in your brain the stroke took place, long-term speech, memory, and movement complications can occur.
- Strokes cannot be completely prevented, but certain lifestyle changes, such as losing weight, getting proper sleep, eating properly, and avoiding smoking and drinking alcohol, can help.
- BIPOC are at a higher risk of stroke, along with people over age 65, men, and those who have underlying health conditions like high cholesterol, high blood pressure, and other heart conditions.
- Stroke treatment may include a combination of surgeries, medications, and rehabilitation programs to regain ability. Recovery time will largely depend on the severity of the stroke and how quickly treatment takes place.
FAQ
What are the signs of a stroke?
Common signs of stroke include numbness, weakness, and inability to move the face, arm, or leg (especially on one side of the body), trouble speaking, confusion, loss of balance, and severe headache. When in doubt, think FAST: face drooping, arm weakness, speech difficulty, time to call 911.
What are the different types of stroke?
There are two main types of stroke: ischemic and hemorrhagic. An ischemic stroke happens when a blood clot blocks proper blood flow into the brain, and a hemorrhagic stroke happens when a blood vessel ruptures or leaks in the brain. Ischemic strokes are more common.
What should you do if you’re having a stroke?
If you think you are having a stroke, you or someone nearby needs to call 911 immediately and go to the nearest emergency room for treatment. Once interventional treatments are given and you are stabilized, doctors will test for any stroke complications and provide recovery plans.
How can you prevent a stroke?
Stroke cannot be entirely prevented. However, certain lifestyle changes — like quitting smoking and drinking, getting regular exercise, sleeping well, and eating a balanced diet — can help reduce your risk.
Resources We Trust
- Cleveland Clinic: Stroke
- National Heart, Lung, and Blood Institute: Recovery
- American Stroke Association: Prevent a Second Stroke
- The Stroke Foundation: Your Trusted Recovery Resource Hub
- Northwestern Medicine: The Differences in Stroke Symptoms Between Men and Women
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
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Meet Our Experts
Huma Sheikh, MD
Medical Reviewer
Huma U. Sheikh, MD, is an assistant professor at Mount Sinai Beth Israel and was previously a clinical instructor of neurology at Brigham and Women’s Hospital–Harvard Medical School. She completed her neurology residency at Montefiore Medical Center, where she also completed a stroke fellowship before going on to Brigham and Women’s Hospital for a fellowship in Headache Medicine. She is the co-chair of the Women's Issues in Migraine at the American Headache Society.
Quinn Phillips
Author
A freelance health writer and editor based in Wisconsin, Quinn Phillips has a degree in government from Harvard University. He writes on a variety of topics, but is especially interested in the intersection of health and public policy. Phillips has written for various publications and websites, such as Diabetes Self-Management, Practical Diabetology, and Gluten-Free Living, among others.