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

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.

A look at the concentrations of water in the human body and various organs

When we're born, about three-quarters of our bodies are composed of water, dropping to an average of 55-60% for the average adult. The lungs are over 80% water, the kidneys and spleen about 80%, and the heart and brain are approximately three-quarters composed of water—about the same moisture as a banana.

Exercise improves brain blood flow, stimulates neural growth, and more

Exercise has dramatic effects on human biology, including reducing some of the long-term harms associated with chronic stress. Its effects are also pronounced in the brain, including improved memory retention, sleep, cognitive functioning, and more.

A pregnant woman's brain sheds gray matter, perhaps explaining 'baby brain'

The brain areas involved in processing information and emotions decrease by an average of almost 5% during pregnancy. Researchers discovered in a 2025 study that this mostly temporary change—the brain hadn't fully returned to its normal size six months after pregnancy—seems to be associated with self-reported improved bonding and less hostility toward the child postpartum.

As much as 10% of home energy use comes from unused, plugged in devices

Vampire or phantom energy includes smart features that keep devices connected to the internet and standby modes that allow quick wake-ups. Turning off these background features or unplugging devices from outlets can help reduce emissions by as much as 20%.

By 2028, data center power consumption may equal 22% of US households

Date from 2023 suggests that data centers accounted for around 4.4% of US electricity consumption, with new facilities supporting the AI boom consuming more power than the state of New Hampshire annually. However, the energy impact of individual use varies widely depending on the prompt and AI model. (Some readers may experience a paywall.)

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.

What is the brain up to when the mind wanders?

As you stare into the distance while washing your home's seemingly never-ending pile of dishes, the brain activates its default mode network. This collection of "task-negative" brain regions associated with memory, reward, action consideration, and prediction alight with activity when humans mentally turn inward, possibly giving rise to the brain's ability to wander and humans' ability to construct internal narratives about the world.

How humans digest food

Every day, the average human eats close to six pounds of food—all of which must be processed by the digestive system. Ten organs collaborate to transform food that the mouth chews into the energy needed to stay alive. (Stretched out, these organs...

Brain activity goes into overdrive around the point of death

Recent studies suggest increased electrical activity in the brain during and after clinical death could be responsible for near-death experiences. Both high-frequency gamma waves (linked to perception and attention) and low-frequency beta waves (related to focus and concentration) increased and became more synchronized across multiple brain regions, potentially resulting in a near-death state of heightened consciousness.

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

Humans may have evolved to need less sleep

Humans sleep less than most primates—but more efficiently. Chimps sleep 9.5 hours with 5% in REM, while humans get seven hours with 25% in REM. Some predict we may one day need just five hours, but for now, our sleep patterns balance rest and function, shaped by evolution and environmental stability.

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

Explore internet usage data, including how humans consume 1.2 billion years of content yearly

About half this time consists of content from social media platforms, where the average user spends about 18.5 hours weekly. An estimated $3.66T was spent on consumer goods by online shoppers in 2025, though nonconsumer goods, such as flights and hotel stays, greatly increase this estimate.

How humans breathe without thinking about it

We breathe without thinking about it thanks to the body’s respiratory system and autonomic nervous system, which controls vital functions. Breathing transports oxygen to the body’s cells to keep them working and clears the body of carbon...

What is metabolic rate?

Read this article to better understand the concept of metabolic rate, which is defined as the amount of energy expended by an organism over the course of a day. Basic metabolic rate (or BMR) is this metabolic rate at rest, during which the body only...

Brain hemispheres control opposite sides of the body without either dominating

Although distinctions exist between the two halves—language processing is left-oriented, and emotions are right-oriented—signals are sent along neural pathways between the hemispheres and across different regions to collectively process information about external stimuli.

Why do humans have such long childhoods?

Humans have over twice as long childhoods than other animals with similar lifespans like whales and elephants. A human child can grow for nearly 20 years before they become a reproducing adult. Researchers believe there's a connection between long childhoods and human's unusually large brain size, though the science is not totally clear. Dive into what scientists know here.

The role of fire in the evolution of humanity's big brains

Roughly 1.5 million years ago, the brain size of our hominin ancestors exploded. To understand why, Richard Wrangham posited the cooking hypothesis, arguing the adoption of fire as a means to cook food had a lasting impact on our ability to digest...

The body's master clock has 20,000 neurons

The suprachiasmatic nucleus, the master clock in mammals, has 20,000 neurons that help maintain the light-dark cycle in the body. Among its jobs: It receives light input information from the retina and then signals peripheral body clocks to act on this information, driving everything from body temperature to hunger.

The average American likely doesn’t notice how many ads they’re targets of per day

The average American is targeted with roughly 5,000 ads each day—but the conscious mind likely isn’t capable of recalling the majority of those. Even still, many consumers have reported ad fatigue due to the near-constant onslaught of ads.

Imagining if humans could perform photosynthesis and how it would change our anatomy

Since chloroplasts reflect green light, becoming photosynthetic would give our skin a green appearance. Because photosynthesis has efficiencies of only 5% to 9%, and humans burn 2,000 Calories daily compared to about 200 burned by a tree, becoming photosynthetic would also require us to adopt a less active, sun-filled lifestyle.

Only 2% of human DNA codes for proteins

The entire human genome contains about 20,000 protein-coding genes, with the rest having initially been categorized as "junk" DNA. However, research since 2003 suggests that this "dark genome" regulates how protein-coding genes are expressed in response to environmental factors encountered by cells.

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.

Why do you shiver when cold?

Humans are warm-blooded creatures, so our bodies like to maintain internal temperatures separate from and typically above those in their environment. This is made possible by a process known as thermoregulation. When the brain's hypothalamus senses a drop in the body's core temperature, skeletal muscles may be ordered to shiver, sending out waves of muscle contractions and exothermic biochemical reactions whose byproduct includes heat and energy.

Studies show AI tools can result in passive learning with less retention

Although ChatGPT, Google's AI overviews, and other similar software can save time, a study of more than 10,000 adults showed that reliance on them yielded work products that were more generic and included fewer facts than those produced solely by Google search. Weaker brain connectivity has also been observed when users write using AI.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

Adults may lose roughly 3% of their muscle mass each decade after 30

That muscle loss, formally referred to as sarcopenia [saar-ko-pee-nee-uh], averages 3% to 5%, depending on physical activity. These losses can progress with age, but resistance training helps combat some of this natural degradation.

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

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

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

Use this calculator to find the dollar value of your mental load, from meal planning to coordinating after-school care for your children.

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.

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Electrical grids worldwide must double their power delivery capacity by 2050 to meet surging demand from AI and electric vehicles.

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.

US housing costs have risen by roughly 175% between 1991 and 2026—but a growing number of Gen Zers are becoming homeowners anyway. In 2025, 4% of homebuyers were Gen Z, up from 3% the year before.

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

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.

Scientists testing how climate change affects plants found, in a years-long simulation study, that poison ivy grew 70% faster with the resulting extra carbon dioxide.

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

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

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.

Doctors differentiate between a phobia and fear by asking patients whether their fear interferes with their day-to-day activities.

The Nasdaq's 'Magnificent 7' companies are responsible for roughly 40% of the Nasdaq 100 index's gains, while the remaining 93 companies account for the other 60%.

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

After the Boston Tea Party, colonists switched to coffee, which became the main morning drink for revolutionaries.

NBA superstar Victor Wembanyama spent the 2025 summer training with monks in central China to enhance his body and mind.