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

Blood leaves the heart at speeds around 12-16 miles per hour

Blood is pumped around the body through the circulatory system, aka the cardiovascular system. This system comprises the heart, arteries, veins, and capillaries. This video is the first in a multi-part series on the circulatory system, focusing on the role of the heart, the pump that powers the entire system.

Pregnancy causes a woman's blood volume to increase by up to 50%

This change, to support the developing fetus, puts stress on the heart and blood vessels. A pregnant woman's heart rate also increases as she pumps more blood each minute to support fetal growth.

Pulsatile tinnitus is when you hear thumping synchronized with your heartbeat

This rare type of tinnitus, which sounds like rhythmic thumping or whooshing, is often linked to blood vessel conditions or high blood pressure. Lowering blood pressure through exercise and food choices can help reduce the severity of this condition.

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...

Ten things to know about your heart

Your heart does amazing things day in and day out. Its main job is crucial: It keeps oxygenated blood circulating throughout your body. Did you know that, other than your cornea, every cell in your body gets blood from your heart? You may not think...

Most things you would get tested for at the doctor’s office are influenced by circadian rhythm

In this video, a Salk Institute Researcher offers daily habit tips focused on aligning with your circadian rhythms. She notes heart rate and blood pressure are highest in the afternoon, for example, and there’s a triglyceride peak in the morning. Generally, she says, it’s a good idea to schedule your doctor’s checkups at the same time of day each year so there’s consistency across your data.

Why don't giraffes get hypertension?

The average blood pressure of a giraffe is about double that of a human, yet they don't suffer from the symptoms of high blood pressure that humans do: stiffening of the left heart ventricle, shortness of breath, fatigue, or swollen legs and ankles. This article explains how giraffes have evolved to have the "biological equivalent of support stockings."

How the heart achieves its first beat

Scientists observed zebrafish embryos as they grew and isolated the several-second-long initial heartbeats to better understand this crucial moment in every heart's life. The zebrafish's heart starts beating 20 hours into their existence. Each heart cell activates electrically at random, without rhythm. As these cells mature, they become more sensitive to electrical charges; as they all fire, a rhythm is established and a pulse is born.

Blood Pressure and Diabetes

New meta-analysis shows blood pressure reductions with ACE inhibitors and ARBs are associated with a lower diabetes risk, but other types of antihypertensive agents have the opposite effect.

The two phases of stress: fast and slow

The physiological response to acute stress generally involves two phases—the "fast" response in which adrenaline is released, and a second "slow" response in which cortisol is released. This technical resource reviews what happens in the body during each phase.

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.

Exercise helps make your arteries more elastic

Regular aerobic exercise releases nitric oxide, a key molecule that relaxes blood vessel walls and improves vascular function. These exercise-induced adaptations make the heart work more efficiently and blood vessels become more elastic, leading to improved circulation and lowered cardiovascular risk.

This site sums up your entire life in statistics

If you’re able to read this statement, a lot has happened since you were born…and these statistics summarize what you have lived through! Input your birthday to find out about how many times your heart has beaten, how many breaths you’ve...

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

Insulin is a hormone that controls blood sugar by helping absorb it into cells

Blood sugar levels increase after a meal when the body starts turning food into usable fuel—sugars, proteins, and more—which are absorbed into the bloodstream through the intestines. Blood sugar levels rise, releasing insulin, and letting sugar in the blood be absorbed into hungry cells, thereby dropping blood sugar levels.

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%.

Love and heartbreak trigger powerful, neurochemical-driven changes in the body

The feeling of falling in love floods the brain with dopamine, oxytocin and serotonin, which collectively dull pain and boost immunity. However, the loss of these chemicals during a break-up produces withdrawal-like symptoms and heart issues, such as high blood pressure.

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.

A tube-and-diaphragm system tells gas pumps when to stop providing fuel

As long as air passes freely through a small hole at the end of the nozzle, the diaphragm is inflated, and fuel flows normally. Once fluid reaches the hole, the change in pressure from the difference in air and fluid densities collapses the diaphragm, which cuts the flow of gas.

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.

VO2 max measures the body's ability to use oxygen to produce energy

VO2 max is the maximum rate at which the body can use oxygen to aerobically produce energy—adenosine triphosphate—for use during intense exercise. Aerobic exercise increases VO2 max, counteracting age-related decline by increasing the body's capillary count and remodeling the heart's left ventricle, increasing the amount of blood it pumps.

Check the real-time price of bitcoin

Bitcoin has gone through several boom and bust cycles. Those peaks and valleys sit on top of a steadily rising value, growing as the currency gains wider adoption. As of 2024, bitcoin’s total market value was over $1.3T, with more than 19.6 million coins in circulation. Still, the value fluctuates.

Up to 400 milligrams of caffeine a day is considered safe

Small, frequent doses can be more effective than large amounts, though caffeine can raise blood pressure and heart rate, especially in people with hypertension. While low doses of caffeine may help with depression by stimulating dopamine, excessive caffeine, particularly from energy drinks, can lead to anxiety and heart issues.

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

Differences in air pressure above and below an airplane's wing allow it to fly

The bending of air around a surface causes it to flow more quickly, reducing the pressure exerted by the airflow. In a commercial airplane, the pressure difference between air diverted above the wing and air flowing undiverted below it creates enough lift to overcome gravity.

Banks make money by loaning customer deposits and earning interest

This means the interest you earn on your deposits is lower than what the bank earns on the same amount. Banks often keep cash reserves (though a minimum requirement was rescinded in 2020) but generally invest in government bonds, corporate securities, and loans to other banks. During bank runs, depositors withdraw more than the bank has on hand.

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.

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.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

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.

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

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.

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.

Explore the animals that populate the depths of the ocean, from fish and coral in the first few hundred feet, all the way down to the bottom of the Mariana Trench.

A century of Billboard issues documenting the evolution of popular music.

Animal phobias are likely the most common type of phobias, followed by an extreme fear of heights.

A pickleball's loud 'pop' sound can reach 120 decibels, which is equivalent to a hammer hitting a nail

Browse a detailed visual analysis of over 200,000 similes—comparisons that often use 'like' or 'as'—from popular fiction to see how frequently writers the same idiomatic expressions.

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.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

The first steps to rebuilding your credit score include getting to know exactly what's on your credit report and figuring out how far you are from the '700 club,' or 'good score' range.

See how Budweiser's famous Clydesdales spend their days at Warm Springs Ranch, where roughly 70 to 80 of the beer brand's giant horses can be found at any given time.

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

Telehealth demand for GLP-1s for weight loss is booming as consumers seek easier access.

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

See a ranking of the best (and worst) Federal Reserve Chairs since 1914 out of the 16 men and women who have held the office since.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

Iran's Revolutionary Guard Corps is independent of Iran's regular army and is one of the most powerful and influential military-political organizations in the Middle East.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.