Sleep paralysis occurs when the body fails to 'unfreeze' in sync with waking

Gibberish, urine, and utter chaos: what happens when you sleepwalk

Sleepwalking, or somnambulism, occurs most frequently in children who are in the deepest stages of sleep. REM, the sleep stage in which most people dream, often causes temporary muscle paralysis, so it’s only when sleepers pass to the deeper stages of sleep that sleepwalking—and sleep talking—can occur.

Narcolepsy occurs when the brain loses its ability to control its sleep-wake cycle

Narcolepsy not only makes people fall asleep at random moments, but it can also cause hallucinations, insomnia, and sleep paralysis. The disorder is tied to cells in the brain’s hypothalamus called hypocretin, which are neuropeptides responsible for keeping you awake and controlling your dreaming from coming on too quickly.

The neuroscience of REM atonia disorders, where patients act out dreams

What prevents the typical person from acting out their dreams? Temporary paralysis of skeletal muscles, usually leading up to, and during, REM sleep. This academic article and related graphics explore what happens when this process doesn't go as planned, leading to REM sleep behavior disorder.

Why do we sometimes jolt awake before falling asleep?

Around 70% of people are estimated to experience the sensation of falling and jerking awake right as they're about to drift to sleep. That mysterious phenomenon is called hypnic jerking. As common as it is, hypnotic jerking remains disconcerting and hard to explain. While we don't yet have clear answers, peruse this article in Popular Science for some possible explanations as to why this happens.

Sleep apnea explained

While sleep apnea is directly tied to an increased risk of cardiovascular and metabolic health problems, many affected people are unaware of their problem. Sleep apnea occurs when upper airway muscles relax during sleep and pinch off the airway, which can cause breathing to pause for 10 seconds or more at a time. Sleep partners (rather than those inflicted) are often the first to notice breathing pauses or loud snoring in their bedmates.

The body's response to cardiac arrest has been linked to near-death experiences

Most people who report near‑death experiences experience events like out‑of‑body sensations, altered cognition, emotional and spiritual shifts, or even supernatural phenomena, particularly during cardiac arrest. Research suggests many such experiences may be linked to brain-generated sensory distortions that can be experimentally replicated, suggesting a physiological rather than mystical cause.

The brain will attempt to rest itself in periods of chronic sleep deprivation

Skimping on sleep lengthens reaction times and blunts decision-making skills. At a certain point, the brain will try to sneak sleep where it can, shifting sections offline even as you remain awake. Going without sleep raises blood pressure, undermines the immune system, and increases one's risk of dementia.

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

Panic attacks are intense fear episodes that often occur without a clear trigger

Unlike typical fear responses to real danger, panic attacks can mimic serious health problems, such as heart attacks. Sweating during a panic attack may seem random, but it's a leftover survival mechanism that made it easier for our ancestors to escape by slipping out of an attacker’s grasp.

The deadly genetic disease that steals shut-eye

Few are haunted by fatal familial insomnia. This neurodegenerative disease is typically carried through bloodlines via genetic mutation of the prion protein gene, forcing the body to create abnormal and pathological protein variations that can corrupt normal versions. This article follows a musician as they attempt to come to terms with the FFI plaguing their family (and, possibly, their future).

Music may give some of us the chills and goose bumps—perhaps because it shocks us

The science is still unsettled about why music can trigger a chill down your spine, formally known as frisson, but one theory is that anything surprising to the nervous system—including sudden beat drops or unexpected harmonies—stimulates a type of alarm response that gives rise to this feeling.

Nightmares are unpredictable, but are linked to stress, anxiety, trauma, and more

Nightmare comes from the terms "night" and "mare," an Old English word for evil, suffocating spirits. Nightmares are parasomnias, meaning they are undesirable events experienced during sleep, and may stem from building tensions in one's unconscious.

While dreaming, the brain connects new information with already-stored memories

During dream sleep, the brain makes connections between new information learned during the day and information already stored in the mind, creating a revised mind-wide web of associations. The dreamer also temporarily becomes confused about time and place and is subjected to a pendulum of strong emotions.

How seizures (potentially) alter consciousness

Seizures occur when intense electrical activity floods the brain, prompting significant loss of self-control and a variety of sensory disruptions and hallucinations. Cultures interpret the episodes differently, with many contemporary norms viewing them as negative while others characterize them as intense spiritual occasions. Author Fyodor Dostoyevsky viewed his seizures this way, as well as cultures in Mongolia, some Shamanic indigenous religions, and others.

Paralysis from polio occurs in under 1% of infections

About 1 in 200 cases of infection causes paralysis. For paralysis to occur, the virus travels from the throat, intestines, and gut to infect specific cells within the spinal cord and brain stem that control movements. Within hours of invading the nervous system, paralysis can occur. The virus can be present in bodily secretions and stool for multiple weeks post-infection.

'1440 Explores' Episode 3: Why We See Ghosts and What Isn't There

Every culture has them—restless spirits, haunted houses, things that go bump in the night. But why do we believe in ghosts? Psychologist and skeptic Dr. Chris French joins host Sony Kassam to explore the science behind the supernatural, from sleep paralysis and hallucinations to the brain's pattern-making instincts. Together, they uncover why our minds see meaning—and sometimes ghosts—where none exist, and what that reveals about fear, memory, and our need to believe in something beyond the grave.

Explore a series of bedtime exercises to improve sleep

Low-impact, mindful movements can potentially help the body and mind relax before sleeping. Such exercises could be a helpful complement to regular exercise during the day.

A deep dive into how a body decomposes

Dead bodies are, understandably, scary and unsettling. Learn about the fascinating process of decomposition that takes place in every human, and how its teeming with life.

Falling into a black hole would stretch and shred your body beyond recognition

As you approach a black hole, you initially feel weightless. Eventually, the difference in gravity between your feet and head would create a powerful stretching force that overcomes the molecular bonds in your body and pulls you apart.

For centuries, it was common to sleep in two shifts: a few hours at the beginning of the night, and a longer period beginning around midnight

How does the body know where it is in space?

Close your eyes and touch your nose. How did you know where your nose was? How could you tell where your hand was? That's proprioception, the sense that keeps your brain apprised of the body's position and movement. This article explains how this sense works, what happens when people don't have it, and what we know about it.

Why don't humans hibernate?

Hibernation is a superpower in the animal world that allows certain species to time travel from difficult times to abundance. This essay in Aeon explains this helpful natural process and why humanity's technological advancements may have hindered our ability to participate in the practice. Learn about the rising interest in human hibernation as a result of modern adversity, and if it could potentially become a reality.

Partial freezing results from trying to freeze water while preventing expansion

Within a sealed container, partial freezing of water increases the contained volume and the pressure, preventing further freezing without decreasing the temperature further. Once cooled below -23 degrees Celsius (-9.4 degrees Fahrenheit), an uncommon type of ice that contracts as it forms is produced, facilitating the complete freezing of the contained water.

BPPV occurs when tiny calcium particles called otoconia become dislodged

WIth this condition, formally known as benign paroxysmal positional vertigo, calcium particles that normally help the brain interpret head movement and position migrate for unknown reasons into the ear's semicircular canals, sending irregular nerve impulses to the brain, which cause intense vertigo episodes.

Slenderman is the most infamous example of creepypasta

In 2014, two teens playing in the woods at the edge of a suburban park turned on their third friend, stabbing her 19 times in an attack they claimed was compelled by Slenderman, a meme-turned-urban legend.

The concept of phantom limbs, the perception that amputated limbs are still present, dates back to a French military surgeon in the 16th century.

Phantom limbs were first documented in the 16th century by a French military surgeon

Ambroise Paré, the military surgeon, observed this phenomenon among soldiers who'd lost limbs, yet the term wasn't formally coined until hundreds of years later, by Silas Weird Mitchell, an American Civil War surgeon.

Schizophrenia increases heat death risks in several complex ways

Evidence shows that people with schizophrenia have an inherently harder time regulating internal body temperatures. They may also struggle to find safe shelter during extreme heat, and their prescribed antipsychotic medications often have dehydrating effects, collectively elevating the risk of heat-related illness and death, as illustrated by this article that focuses on the final days of Stephan Goodwin's life in 2022. (Some users may encounter a paywall.)

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

See these 16 pieces of art evoking phobias of snakes, flying, spiders, and more. 

The first horror movie is believed to be George Méliès' 1986 short 'The Haunted Castle,' which pioneered the use of special effects

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.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

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

Stars appear to twinkle because turbulence in the motion of molecules in Earth's atmosphere causes light to bend and wiggle rapidly on its way to the surface—a phenomenon called scintillation.

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.

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

In 1945, Surrealist artist Salvador Dalí and legendary animator Walt Disney began collaborating on a short film that was not completed until 2003, years after both men had died.

Explore chaos in this simulation of two double pendulums, where small differences in the release angles produce wildly different outcomes.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

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.

In 2009, the nation was gripped by the story of a missing young boy who was believed to be floating over Colorado in a homemade balloon, until it was revealed that he was at home the whole time.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.