A stroke happens when blood flow to part of the brain is cut off or when a blood vessel in the brain bursts. Without a steady supply of oxygen-rich blood, brain cells begin dying within minutes. More than 795,000 people in the United States have a stroke every year, and it remains one of the leading causes of death and long-term disability.
The Two Main Types of Stroke
About 87% of all strokes are ischemic, meaning a blood clot or fatty deposit blocks an artery that feeds the brain. The blockage can form right in the brain’s blood vessels or travel there from somewhere else in the body, often the heart. This is the same basic process behind a heart attack, just happening in a different organ.
The remaining 13% are hemorrhagic strokes, caused by a blood vessel in the brain leaking or rupturing. Blood spills into or around brain tissue, creating pressure that damages cells. Hemorrhagic strokes are less common but tend to be more severe.
There’s also a transient ischemic attack, sometimes called a “mini-stroke.” A TIA produces the same symptoms as a full stroke, but blood flow is only briefly interrupted. Most TIA symptoms disappear within an hour, though they can last up to 24 hours. A TIA is a serious warning sign: it means the conditions for a major stroke are already in place.
Recognizing the Symptoms
Stroke symptoms appear suddenly and can be remembered with the acronym BE FAST:
- Balance: sudden loss of balance or coordination
- Eyes: vision changes in one or both eyes, including double vision
- Face: drooping on one side of the face
- Arms: weakness in one arm or leg (if you raise both arms and one drifts downward, that’s a concern)
- Speech: slurred words or difficulty speaking and understanding others
- Time: call 911 immediately
These symptoms can appear in any combination. Some people experience only one, while others have several at once. The hallmark of a stroke is that everything happens fast and typically affects one side of the body. A sudden, severe headache with no known cause can also signal a hemorrhagic stroke.
Why Time Is Critical
Brain tissue dies quickly without blood flow, so every minute matters. For ischemic strokes, a clot-dissolving medication can be given within a window of about 3 to 4.5 hours after symptoms begin. Patients treated in that window have meaningfully better outcomes: one major trial found a 7% absolute increase in good recovery at 90 days compared to those who missed the window. For large clots blocking major brain arteries, doctors can also physically retrieve the clot using a catheter-based procedure, which has its own time constraints.
This is why the “T” in BE FAST matters so much. Waiting to see if symptoms pass on their own costs the brain cells that treatment could have saved.
What Raises Your Risk
High blood pressure is the single most important risk factor for stroke. It damages artery walls over time, making them more prone to blockages and ruptures. Current guidelines recommend keeping blood pressure below 130/80 for people who have already had a stroke or TIA, and below that same threshold for general prevention.
Several other conditions raise your risk significantly:
- Atrial fibrillation and other heart conditions: irregular heart rhythms allow blood to pool and form clots that can travel to the brain. Heart valve defects and enlarged heart chambers carry similar risks.
- High cholesterol: excess cholesterol builds up inside artery walls, narrowing them and restricting blood flow to the brain.
- Diabetes: high blood sugar damages blood vessels throughout the body, including those supplying the brain.
- Obesity: raises bad cholesterol and triglycerides while lowering good cholesterol, and increases the likelihood of high blood pressure and diabetes.
- Previous stroke or TIA: having one stroke substantially increases the chance of having another.
Sickle cell disease is also a notable risk factor, particularly for ischemic stroke in Black children, because abnormally shaped red blood cells can get stuck in blood vessels and block flow to the brain.
What Happens After a Stroke
The effects of a stroke depend on which part of the brain was damaged and how much tissue was lost. Some people recover almost fully. Others face lasting challenges that reshape daily life.
Physical impairments are the most visible. Many stroke survivors deal with weakness or paralysis on one side of the body, difficulty walking or maintaining balance, and trouble with fine motor tasks like buttoning a shirt. Swallowing problems are also common and can make eating difficult in the early weeks.
Cognitive effects are less obvious but equally disruptive. Memory, attention, problem-solving, and judgment can all be affected. Some people struggle with planning tasks they used to do automatically, like cooking a meal or managing finances. Communication difficulties range from slurred speech to a deeper impairment called aphasia, where finding or understanding words becomes hard even though intelligence is intact.
Emotional changes catch many survivors off guard. Depression is common after a stroke, driven both by changes in brain chemistry and by the grief of lost abilities. Anxiety, frustration, and personality shifts are also well documented.
What Recovery Looks Like
Rehabilitation typically starts in the hospital within days of the stroke. The goal is to retrain the brain and body using the brain’s ability to form new neural connections, a process called neuroplasticity. Recovery is most rapid in the first few months, but meaningful improvement can continue for a year or longer.
A rehab program usually involves several types of therapy working together. Physical therapy focuses on rebuilding strength, balance, and the ability to walk. Occupational therapy helps with everyday tasks like dressing, eating, and managing a household. Speech therapy addresses not just speaking difficulties but also problems with understanding language, reading, and writing. Psychological support is woven in to address emotional adjustment and cognitive rehabilitation.
The intensity and duration of rehab vary widely. Someone with mild weakness might need a few weeks of outpatient therapy. A person with significant paralysis or communication loss might work with therapists for months, first in an inpatient facility and then at home. Progress is rarely linear: good weeks and frustrating plateaus are both normal parts of the process.
Reducing Your Risk
Because high blood pressure drives so many strokes, managing it is the single most effective thing you can do. Regular physical activity, limiting sodium, maintaining a healthy weight, and taking prescribed medication if needed all help keep blood pressure in a safe range.
If you have atrial fibrillation, treatment to prevent clot formation is especially important. Managing cholesterol and blood sugar also directly lowers stroke risk. Smoking damages blood vessels and accelerates the arterial narrowing that leads to ischemic strokes, so quitting has an outsized benefit. In the United States, 1 in 6 cardiovascular deaths is due to stroke, but many of those strokes are tied to conditions that respond well to prevention.