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

Brain death is a top source of organ donation

Brain death is a significant source of organ donations—approximately 40% of organs in the US and the UK are recovered from people who experience brain death. Patients declared brain dead and hooked up to intensive care unit machines will still have oxygen flowing to organs like the heart, lungs, and kidneys—preserving those organs.

Brain death is a medical diagnosis without any wiggle room

Seeking to resolve long-standing variations between hospitals and state procedures, in 2023 several expert groups published comprehensive step-by-step guidance for clinicians to follow when determining brain death in kids and adults. Among other guidelines, it stated that doctors don't need to get family consent to do the tests needed to make this determination.

Brain death is a uniquely modern problem stemming from modern ventilators

Patients who would have once died from devastating brain injury can now live on a ventilator for a long period of time, creating ethical, medical, and legal dilemmas.

In 1968, a Harvard Medical School committee issued the first neurological definition of death

The definition set a legal and medical precedent for how we define death, important for issues including organ donation. This 2020 video podcast discusses the history of brain death controversies and the variability in how death has been determined, including discussions in the late 1960s about when patients are considered dead in the context of organ donations.

Four in 10 CPR patients report consciousness not captured by standard measures

A recent study found people revived by CPR after cardiac arrest reported they experienced some amount of consciousness during clinical death, suggesting our brains are capable of thought and memory for significantly longer after death than previously thought.

Traumatic brain injury is a leading cause of brain death—and TBIs are trending up

Traumatic brain injury-related deaths have generally increased between 2000 and 2023, growing from roughly 49,000 to more than 68,000 in 2023. Firearm-related suicide is the most common cause of TBI-related deaths in the US, according to the Centers for Disease Control and Prevention. People also experience TBIs from falls, motor vehicle crashes, or assaults.

Scientists are studying dying patients' brain activity in the final moments of life

In the final moments of life there are distinctive bursts of coordinated neural activity. Researchers are interested in parsing that data to better understand the dying process and also exploring how this data relates to our understanding of consciousness.

Heatstroke deaths may be massively undercounted—perhaps by a factor of 10

One often-cited average estimate of annual American heat deaths—roughly 1,200 per year—is based on death certificate data, but it may be a significant undercount because heat kills through cardiovascular, kidney, and respiratory causes that are more likely to be cited on those documents. (Separate analysis that looked at data from 1999 to 2023 found that the highest number, in 2023, was 2325.)

Hemorrhagic strokes make up roughly 13% of stroke events

A hemorrhagic stroke occurs when a faulty blood vessel within the brain bleeds. Though this is less common than an ischemic stroke, it is often far more deadly. This in-depth resource from the American Stroke Association provides a comprehensive overview of the two main subtypes of hemorrhagic stroke along with a useful animation of the condition.

In 2023, at least 6 people were charged with stealing body parts

A recent case involving alleged trafficking in stolen human body parts charged that there was a nationwide network of individuals who bought and sold human remains. The charges alleged, among other things, that from 2018 through 2022, the manager of the morgue at Harvard Medical School's Anatomical Gifts Program stole organs and other parts of cadavers that had been donated for medical research and education. In late 2025, that Harvard morgue manager was sentenced to 96 months in prison.

The human brain only uses 5% more energy during active tasks versus resting

Despite only being 2% of the weight of a human body, the average adult brain consumes 20% of its energy, with the majority of it spent on maintaining homeostasis—the stable equilibrium conditions of temperature, acidity, blood sugar, and other properties in the body. For infants, the consumption is closer to 50%.

Each day, about 60 US pregnancies end in stillbirth

This online memorial for families who experienced the unexpected death of a fetus 20 weeks or older is the result of ProPublica reporters inviting 60 families to share their baby's name and answer some questions about their unfulfilled wishes for their children. About 21,000 babies are stillborn in the US annually. About the same number of children die in the US during their first year of life.

More than 40 states have passed versions of the Uniform Declaration of Death Act

The 1981 model law, now enacted in most states, is the legal basis for death in the US. There have been many efforts to amend this law, citing the need for more transparency to improve trust between families and the medical profession, though none have moved forward. Alterations to the law could have implications for organ donations and removing life support.

Sepsis is the leading cause of death in hospitals

Sepsis is the result of an overly aggressive immune system trying to combat infection, triggering inflammation throughout the body. After it begins, each passing hour increases the risk of death by 4% to 9%, and an estimated 350,000 people die from the condition in the US each year.

Around 5% of people report memories of a near-death experience

Near-death experiences are moments reported by people who’ve come close to death, often associated with bright lights, out-of-body sensations, or encounters with otherworldly beings. While scientific research offers theories ranging from brain chemistry to psychological coping mechanisms, no single explanation fully captures the mystery of these experiences.

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.

Most Americans are now dying at home, reversing 20th century trends

For most of the 21st and 20th centuries most Americans died in hospital settings. But in 2016, home-based deaths overtook hospitals; most Americans are now dying at home, likely fueled by individual preferences to die at home or to receive at-home palliative care.

Historically, only about 1% to 2% of Americans had to pay the federal estate tax

Recent IRS data shows that between 2011-16, that number dropped even lower: The federal estate tax only impacts about 0.2% of Americans. Death taxes typically only impact the rich, and the federal estate tax is no exception.

Black Americans with diabetes have amputation rates three times higher than average

Annually, 130,000 US diabetics undergo amputations due to complications from diabetes, with many patients located in low-income and uninsured neighborhoods. More than half of US diabetics who lose lower limbs are not subject to pre-surgery angiograms, imaging that shows blood flow blockages to determine if (and where) amputation is necessary.

Yes, you can die from a broken heart

Researchers reviewed the health records of about 200,000 people diagnosed with broken heart syndrome from 2016 to 2020 and the death rate was 6.5%—with men's deaths roughly doubling that of women.

Breast, prostate, and lung cancer are the most common forms of the disease

Close to 1.8 million cases of cancer are diagnosed each year in the US, with more than 600,000 deaths (about 0.2% of the total population). This visualization tool offers a searchable database of aggregate statistics on common cancers by gender, race, state, and other demographic information.

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

Most cells undergo programmed, controlled death

In the average adult human, apoptosis occurs in 50 billion to 70 billion cells daily when proteins managing a cell's life cycle send signals that the cell is damaged, causing it to break apart into smaller pieces that are consumed by white blood cells. The consumption prevents damage from spreading via cell division.

Recent research found that the brain doesn't seem to massively rewire following amputation—upending earlier beliefs about the cause of phantom limb pain.

Grip strength predicts death better than blood pressure

In a study covering about 140,000 people across 17 countries, scientists found that for every 5 kilogram drop in adults' grip strength, it raised the risk of death by 16%. Grip strength, the research found, was a stronger predictor of cardiovascular death than systolic blood pressure.

How much your blood really costs

In the US, donating plasma twice a week can earn you $400 a month. But this system only works by targeting people who need the money most. Plasma clinics are placed in low-income zip codes, and frequent donation may increase health risks.

Analysis finds dementia was rare in ancient Greece

Ancient medical texts seldom mention severe cognitive decline, suggesting that such conditions were uncommon. This scarcity is attributed to factors like shorter lifespans and active lifestyles, implying that modern environmental and lifestyle changes—along with longer life expectancy—contribute to the current prevalence of dementia.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

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.

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

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

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.

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.

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

Against his wishes, Albert Einstein's brain was removed before his cremation, and the pathologist responsible stored it for decades in mason jars within a beer cooler.

The USPS spent $3.97B in 2024, accounting for .058% of the federal budget.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

Roughly 43 million US borrowers owe roughly $1.7T in student debt, the second-largest source of consumer debt behind mortgages.

The United States is one of only around two dozen countries with a fully federal system of government, in which power is divided between national and state governments.

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.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

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.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

The 1987 Nintendo video game 'Stadium Events' isn't known for being particularly fun, but its scarcity has made it a highly sought-after item that has sold for up to $35K at auction.

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

Domino's Pizza's 30-minute delivery guarantee was responsible for the chain's 1980s surge, but it was discontinued after the company was found liable for delivery driver accidents.

Neutron stars, the remains of some massive stars after they explode in a supernova, are the densest directly observable objects in the universe.

When you complete a CAPTCHA on a website to prove you are human, you may be unknowingly training algorithms for self-driving cars, whose systems require training data to help identify crosswalks, bicycles, and other outdoor objects.

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.