It is recommended that humans consume 2.0 to 3.7 liters (about 4.2 to 7.8 pint glasses) of water daily to replace water lost through breathing, sweating, urination, and bowel movements.

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.

Extreme heat puts people at risk of developing kidney stones

It's essential to remain hydrated in summer weather to keep your body healthy, but one reason is to help dilute minerals that naturally build up if they aren't excreted in our water-fueled urine. Doctors recommend people generally drink 64 ounces of water a day and also eat foods with salt to help ward off dehydration.

Each second, the human body produces 2 million to 3 million new red blood cells.

Explore an interactive map of global water gaps, caused by human consumption surpassing the rate at which water reserves are replenished by the hydrologic cycle.

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%.

Earth's easily accessible surface water in rivers and lakes accounts for about 0.01% of all the water on Earth, but 70% of this surface water is used for agriculture.

How often should you clean your water bottle?

Experts say a daily wash of a high-use bottle is key to keep away unwanted bacteria and odors. For a good clean, use water—as hot as 140 degrees Fahrenheit—mixed with soap, swirling the mixture in the bottle before letting it sit for 20 minutes. Learn more tips with this quick overview.

How the body produces urine

Things seem so simple when nature calls. But, how does the body actually produce the urine we so regularly and thoughtlessly expel? This detailed, comprehensive animation walks viewers through every step with precise illustrations, from the kidney's filters (known as nephrons) to the direct nerve connecting the bladder to the brain. See how the body does it here.

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...

Recent global health estimates suggest that inactivity is a leading risk factor for death, contributing to 6% of deaths worldwide.

Humans need higher levels of water-soluble vitamins that easily pass through the body

There are two types of vitamins: lipid soluble and water-soluble. Water-soluble vitamins like B vitamins and vitamin C are in the watery parts of fruits and easily pass through the human body before being taken up by the bloodstream or exiting your body. But lipid (fat) soluble vitamins must be absorbed through the intestinal wall, carried by proteins, and then may be stored in the liver and other body parts—meaning there is greater risk of overdosing.

Health officials recommend at least 150 minutes of aerobic exercise per week and 2 sessions of resistance training, targeting each major muscle group.

The strange endurance of consuming blood for health

Blood's importance to humanity is best summarized this way: without it, we die. This importance naturally begets assumptions about its medicinal properties, many of which appear accessible through drinking or eating the fluid connective tissue. This article details the history of blood drinking, from ancient Roman gladiators to modern-day sanguinarians.

Optimal human functioning requires movement

There is now ample evidence to back the centuries-old hypothesis that exercise is critical to human health. This review article explores the latest discoveries in exercise science, including how exercise is intrinsic to maintaining our organ systems throughout life.

Visualize water's abundance across the solar system, and its relative rarity on Earth

Despite covering almost three-quarters of its surface, water only makes up about 0.12% of Earth's volume. Water in some of Jupiter's and Saturn's moons comprises a larger share of those celestial bodies and of the total water in the solar system. For example, Jupiter's moon Ganymede is believed to harbor almost nine times Earth's oceans beneath its icy shell.

Adults need 2 days of muscle-strengthening activity weekly—yet most of us aren't doing that.

Normal body temperature varies from one person to another; it's not uniformly 98.6 F, as physician Carl Wunderlich determined in the 1800s.

Earth's first oceans may have been as much as 230 degrees Celsius (446 degrees Fahrenheit), with atmospheric pressure preventing them from boiling.

The plasma-selling industry is expected to reach $50B by the end of the decade

About 55% of your blood volume is plasma, the liquid part of blood created from water, proteins, minerals, and salts absorbed through the digestive tract. This 49-minute podcast episode explores the business of plasma—part of a global industry expected to be worth $50B by 2029.

Seven things you might not know about blood

The red stuff currently pumping throughout your body is a type of connective tissue that is both a solid and a liquid. The liquid portion—plasma—acts as a carrier for the solid portion, which includes blood cells and their biological brethren. Your body is constantly refreshing its supply of blood, creating new cells to replace those that have expired or died. This article overviews some lesser-known facts about blood (and why it's not always red).

Explore the water footprint of producing various proteins, fruits, and vegetables

This interactive gallery highlights the various types of water behind the production of biofuels, foods, and materials such as cotton. Diets high in bovine meat, whose production requires 15,415 liters of water per kilogram (1,847 gallons per pound), are among the most water-intensive, whereas every kilogram of vegetables uses 322 liters of water (39 gal/lb) to produce.

The numbers on US wine consumption

Ever wonder how much wine the average American drank in 1949? Wonder no more! The answer is 0.89 gallons. That’s way less than 2022, where the number has quadrupled to 2.86 gallons. Check out this simple table that tracks average United States wine consumption from 1934 through 2022, by individuals and as a whole. American wine consumption peaked during the early pandemic but has lessened since then.

Forty to 110 minutes of deep sleep is recommended per night

Adults typically spend 10% to 20% of the night in deep sleep, also known as slow-wave sleep, with the rest of the night spent either in light sleep or REM states.

Microplastics have been identified across human body systems, with research finding they are most commonly ingested through inhalation, drinking water, and diet before crossing barriers into organs.

Studies suggest when you sleep is as important as how much you get.

Technologies developed for the ISS have brought benefits to people on Earth

About 93% of water used onboard the International Space Station is recycled through filtration and purification systems that have since been used in regions lacking access to clean water. Treatments to mitigate bone loss and muscle atrophy in astronauts can also help aging adults.

Heatstroke treatment guidelines were built almost exclusively on research in men

Protocols for the standard treatment recommendation for heatstroke—whole-body cold water immersion—were built based on studies almost entirely in men. The research wasn't replicated in women, who typically cool faster than men during cold water immersion, raising questions about standard protocol safety for women, due to the risk of overcooling.

Each part of the human body experiences aging differently

With global average life expectancy cresting at 73 years, understanding how the body ages is imperative to effective medical treatment and maintaining a desired quality of life. This 13-minute video dives into how the body and its organs age "from head to toe."

The human body relaxes upon death, including the bowel and bladder, expelling urine and feces

Watch a hospice nurse walk through how death affects the human body and what to expect in the hours and days following the death of a loved one as the body breaks down.

Although consuming saltwater can dehydrate and kill organisms, some fish survive by using specialized gills that leach excess salt from their bodies back into the surrounding water.

Mosquitoes drink a maximum of 0.01 milliliters of blood in a single meal.

Oral rehydration solution was developed in the 1960s in response to cholera deaths.

As of 2022, scientists estimate that 117 billion people have been born on Earth

Although no demographic data exist for more than 99% of the time humans have existed, this value can be estimated by tracking approximate population sizes over different periods and the birth rates within those periods. In 2022, about 6.8% of humans that have ever been born were alive.

Our bodies cool us down by sweating because water requires a significant amount of energy to change state from liquid to gas, making it an ideal medium for carrying thermal energy away from our bodies.

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.

Bone marrow generates roughly 500 billion new blood cells each day.

When users prompt AI chatbots, both cooling systems that support data centers and power plants that rely on steam cycles to generate electricity for data centers contribute to water use.

To survive underwater hibernation, some freshwater turtles perform cloacal breathing—blood vessels absorb dissolved oxygen from water drawn into the organism's cloaca, or rear orifice.

Learn how aquifers and wells provide the largest reserves of accessible freshwater on Earth

Roughly a third of Earth's freshwater is stored underground in aquifers—permeable and porous rock formations where water naturally flows from the Earth's surface and accumulates. About half of this groundwater is accessed through wells, a feat of engineering used for thousands of years.

View a map of countries with the safest and most dangerous drinking water

More than a quarter of the world's population lives in water-stressed countries, and a similar number use contaminated drinking water sources, which can lead to widespread disease, according to the World Health Organization. The Environmental Performance Index shows which countries have safe drinking water.

Blood pressure readings correspond to the peaks and valleys of heart beats

Pushing 2,000 gallons of blood through the body every day exerts a force known as blood pressure. Blood pressure is highest during the heart's contractile phase, known as systole, which forces blood through the circulatory system, and lowest during the heart's resting phase between beats, known as diastole.

Local governments are responsible for more than 148,000 public water systems across the US

From large municipal utilities to small rural systems, local governments are tasked with providing clean water to almost every American community. The US operates over 148,000 public water systems.

Human anatomy 101: the body's systems

Human life is made possible by the body's ten major systems, which maintain homeostasis by responding to incoming sensory and biochemical input. Each system must work independently and collaboratively for the body to maintain health and respond appropriately to its internal and external environments. The bones of the skeletal system, for example, give the body its shape and protect organs while also facilitating movement with the muscular system.

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...

How much sleep do you need?

When it comes to how much sleep you need, age matters—and, for your health, it's important to be well rested. Young children between the ages of one and three need the most sleep: It’s recommended that toddlers get between 11 and 14 hours of...

How water pressure affects the body

The extreme conditions of the deep sea include increasing amounts of pressure as explorers and organisms descend into its depths. The major danger for both fish and humans is the way pressure changes how body tissues absorb chemical molecules...

An interactive guide to the cardiovascular system

The cardiovascular or circulatory system moves blood throughout the body, ensuring cells have necessary nutrients and removing any waste. Click through this interactive 3D guide to explore the system as it crisscrosses the body via arteries, veins, and capillaries. This guide also includes similar breakdowns of the body and its other processes.

Gulf nations produce about 40% of the world's desalinated water

According to a 2023 report, six Gulf states produced 1.9 trillion gallons of freshwater across more than 400 desalination plants along their coasts. These plants create water suitable for human consumption by boiling saltwater and collecting steam or using high-pressure pumps to push seawater through a filter that only allows water molecules through.

The Great Lakes hold almost 20% of the world's surface freshwater

Formed by retreating glaciers, the Great Lakes system feeds Niagara Falls through the Niagara River. Together, the lakes contain about 23 quadrillion liters (5,400 cubic miles) of water, enough to cover the land portion of the continental US to a depth of 3 meters (9.84 feet).

Since 2022, two-thirds of data centers have been built in water-stressed areas

In residential evaporative cooling systems, 10% of consumed water is lost to evaporation compared to 80% in data centers. Although some companies have pledged to become water-positive—replenishing more freshwater than they consume—by 2030 through a transition to air cooling, only 10% of data center operators track water use across all their facilities.