Someone suffers from a stroke every 40 seconds

An estimated 2 million brain cells die each minute a stroke goes untreated

Modern stroke treatment is a delicate balance between obtaining an accurate diagnosis and delivering treatment quickly. Each stroke has its own cause, and the appropriate treatment must be paired with the correct diagnosis to prevent further harm. Typical treatments pair emergency surgery to relieve the affected area and long-term regimens to avoid recurrence.

Strokes are caused by abrupt stoppage of blood flow to the brain

A stroke occurs when blood flow to part of the brain is suddenly interrupted, either by a blockage (ischemic stroke) or bleeding (hemorrhagic stroke). Each year, nearly 800,000 Americans experience a stroke, with around 85% of them being ischemic.

Medical recognition of strokes stretches back to ancient Greece

Every minute, 750 milliliters of blood flows to the brain, supplying 20% of the body’s oxygen. A sudden disruption—whether from a clot (ischemic stroke) or a bleed (hemorrhagic stroke)—can be life-threatening. From ancient Greek theories to modern CT and MRI scans, here’s how stroke science has evolved over time.

Visualizing a stroke at the microscopic level

By far the most common type of stroke is what is known as an ischemic stroke. This occurs due to either an embolus (a blood clot that travels to the brain from elsewhere in the body) or a thrombus (a blockage that forms within the brain itself).

Take a quiz to discover your brain care score

Each year, nearly 800,000 Americans have a stroke. With such a high occurrence rate, you may be asking yourself what you could do now to prevent a future stroke. Researchers at Harvard collaborated to answer this question by coming up with a "Brain Care" scoring system. Take the quiz to learn the quality of your brain health today and pick up helpful insights to lower your risk of stroke and dementia well into the future.

Left versus right brain strokes vary significantly in long-term effects

Due to the high complexity of the brain, the aftereffects of a stroke can have widely different manifestations, ranging from minor temporary impairments to rapid death. Whether a stroke results in paralysis, speech impairments, loss of bodily function, or death will depend on whether it occurs in the left or right hemispheres or the brain stem.

A brain scientist's experience with a stroke

What happens when a leading brain scientist has a stroke of her own? Dr. Jill Bolte Taylor recounts moment by moment watching her brain function slow and then cease, followed by a prolonged recovery. Through this experience, she details what she learned about the phenomenon of stroke and how it has impacted her research ever since.

Stroke risk doubles each decade after age 55

While age is the greatest risk factor, genetics, diet, and overall health play a prominent role in determining individual stroke risk. Prevention focuses heavily on modifiable risk factors. High blood pressure is the single most important controllable risk factor, contributing to both types of stroke.

'FAST': An acronym to remember stroke symptoms to look for

The primary factor in surviving a stroke is how quickly one gets the appropriate medical treatment. “FAST” refers to the four most noticeable symptoms of a stroke: face-dropping ("F"), arm weakness ("A"), speech difficulty ("S"), and "time to call 911" ("T").

How tPA, which helps dissolve blood clots, can lessen the severity of a stroke

One of the most exciting recent advances in treating stroke is a medication known as tissue plasminogen activator, or tPA. It is only effective for use in some ischemic strokes, and it must be delivered within 4.5 hours of symptom onset to have a chance at working.

Brain death is very rare—only 2% of hospital patients have brain death in the US

A peer-reviewed analysis examining US hospital billing code data from 2012 to 2016 concluded that the incidence of brain death is about 2% in the country. There was no available information indicating what proportion of those patients underwent organ donation.

Roughly 1 in every 4,300 individuals in the US has mitochondrial disease

Roughly 1,000 to 4,000 kids are born with these conditions each year in the US though many of the diseases are fatal. Mitochondrial disorders often affect the organs that require the most energy, including the heart, brain, and muscles.

One in 10 adults worldwide has diabetes

As of 2021, diabetes claimed at least 6.7 million lives and continues to kill one person every five seconds. Nearly one in two adults with diabetes don't know they have the condition, which is expected to increase in prevalence from 537 million in 2021, to 783 million in 2045.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Five to ten percent of Alzheimer's cases are early-onset

Early-onset Alzheimer’s typically emerges around 40 to 50 years of age, with devastating effects. This video follows Brian, diagnosed with the disease at age 54, as he travels the country as an advocate for research and discusses the progressive mental fog of Alzheimer’s.

Ending daylight saving time may prevent as many as 300,000 strokes annually

Changing clocks twice a year disrupts circadian rhythms, which last an average of 24 hours and 12 minutes. Studies have shown that permanent daylight saving time provides fewer health benefits than standard time.

Between 2006 and 2021, 444 people died from lightning strikes in the US

The National Oceanic and Atmospheric Administration reports that the odds of being struck by lightning in one's lifetime are one in 18,864. Participation in outdoor activities during the summer months in Florida, Texas, and Colorado increases one's risk of exposure.

Overwork contributes to thousands of worker deaths

Can work really kill you? The World Health Organization and the International Labor Organization have estimated that long work hours contribute to thousands of death from strokes and heart attacks each year. This BBC article argues that the culture of overwork and burnout is leading to a public health crisis in desperate need of solutions.

A beginner’s guide to the brain

Small but powerful, the brain constitutes only about 2 percent of the human body. However, it runs jus about everything, day and night, all year round. Learn about the different parts of the human brain, as well as its unique defenses, like the blood brain barrier in this four-minute video.

Prostate cancer is both manageable and the second-deadliest cancer for men

One in 44 men in the US will die from prostate cancer, while one in eight will be diagnosed with it. Commonly viewed as the safest cancer to have, screenings can save lives—but they can also cause complications for otherwise benign cases of the disease.

One person dies from opioids every 7 to 8 minutes

This collection of infographics by the National Institute for Health Care Management helps put the crisis into perspective. The opioid epidemic has had three waves. Opioid-related deaths increasingly involve synthetic versions of the drug class, contributing to 83 percent of all opioid-related deaths in 2020. Use these infographics to learn more about the crisis.

Migrane 101: data, symptoms, and treatments

Living with migraine, however often the neurological condition attacks, is a journey fraught with pain and isolation. This migraine guide offers insight into the condition, common triggers, possible treatments, personal stories, and tips for managing life with migraine.

There have been close to 40 Ebola outbreaks since 1976

Ebola is a rare but deadly virus that causes severe illness, organ damage, and sometimes internal bleeding. It spreads through contact with infected bodily fluids and is most common in parts of sub-Saharan Africa. This explainer covers its symptoms, transmission, and treatment options.

Ebola infects and disables immune cells, triggering a cascade of events that leads to small blood clots throughout the body, weakening blood vessels and interrupting blood flow to key organs.

'Blackout challenge' can cause brain damage or death in under 5 minutes

A social media trend that encourages viewers to asphyxiate themselves until they lose consciousness in the hopes of feeling "high" or euphoric has garnered the interest of teens and adolescents, with dangerous results. Variations of this deadly challenge have been adolescent trends every few years.

The mysterious details of Stalin's death

The 73-year-old dictator of the Soviet Union died March 5, 1953, officially from a stroke, on top of nearly a decade of significant medical issues. But evidence suggests the longtime leader might have been poisoned less than a week before at an intimate gathering of Stalin's closest confidantes and advisors. Explore the current evidence for Stalin's alleged murder here.

Roughly one in every 250 has never remembered a single dream

Most people dream for about two hours every night and recall about two dreams per week, and memory encoding is especially fragile upon waking. Alarms can knock dreams right out of one's head, and dream recall may be influenced by personality, interest, and socialization.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

About 2,000 US babies are born annually without some portion of their limbs, potentially leading to a lifetime of pricey prosthetics.

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

11 people died from firework injuries in the US in 2024.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

US consumers collectively owe more than $1T to credit card companies—almost as much as they owe in auto loans.

About 12.5% of US adults experience a phobia in their lifetime, a diagnosis that hinges on the intense fear interfering with daily life and persisting for at least six months.

Between 10 million and 50 million people in the US develop rashes from poison ivy, poison sumac, and poison oak each year.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

Experimental hantavirus vaccines and therapies, still under development, have long been funded by the US military.

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

This site reaches millions of visitors who are tired of AI chatbots and seeking human connection. Pretend to be an AI chatbot and ask questions, provide answers, and draw for people in real time.

44% of Americans say they pray at least once a day—discover how your state's religiosity stacks up against the rest of the country.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Art theft is the third-largest source of criminal revenues worldwide, thanks in part to the subjective nature of valuing a work of art.

US intelligence allegedly pursued more than 600 schemes to assassinate Cuban revolutionary Fidel Castro.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

A Yale student wrote a profound essay about the consulting industry's influence on elite college students that was published in a book of her writing after she died in a post-graduation car accident.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

Explore fun facts from the USPS, including unique post office buildings, a stamp that traveled past Pluto, and more.

Learn how to read a prospectus, the juicy document that any company must file with the SEC before going public.