13 Facts About Vertigo

Illustration by Mental Floss. Images: iStock
Illustration by Mental Floss. Images: iStock

It comes on suddenly. You feel like you're spinning—or maybe the world is spinning around you. Your stomach heaves, and you hold onto something so you don't fall. This is vertigo, a hallucination of motion—a mismatch between reality and the signals your eyes, inner ears, and sense of touch are sending your brain. Vertigo is a symptom, not a disease—an indication that something is wrong in the body—and it's surprisingly common. Here's what you need to know about the condition.


Dizziness is an umbrella term that describes the sensation of feeling lightheaded or faint. As kids, many of us experienced (and even enjoyed) that kind of garden-variety dizziness while spinning on a merry-go-round, but the sensation can also be caused by dehydration, motion sickness, or even a drop in blood pressure after standing up too fast.

While vertigo does make you dizzy, it also makes you feel like you’re spinning, swaying, or tilting. Some people with vertigo sense their bodies moving in space even though they’re standing still, while others sense their surroundings moving around them. A good way to tell you're experiencing vertigo and not just dizziness is that you feel like you're going to lose your lunch: “A person with vertigo can feel ill with nausea, vomiting, and other motion sickness-like symptoms,” says David Zee, a neurologist at Johns Hopkins University and a specialist in vertigo.


The name refers to the system located in parts of the inner ear and the brain that control balance and eye movements. The most common vestibular disorders often induce vertigo. Others include bilateral vestibular hypofunction (which causes balance problems), acoustic neuroma (a kind of benign tumor that can cause tinnitus or hearing loss), and a variety of autoimmune inner ear diseases.


Doctors split vertigo into two categories: peripheral or central. The former, which originates in the inner ear, is far more prevalent than the latter.

The most common form of peripheral vertigo is benign paroxymal positional vertigo (BPPV). BPPV comes on quickly, causing disorientation and stumbling; some even fall out of bed. (People can mistake it for a stroke, and not without reason—sudden vertigo and loss of balance experienced at the same time can be signs of one.) Most episodes last about a minute and recur over a period of a few days or weeks.

The majority of peripheral vertigo is caused by otoconia (also called canaliths), tiny limestone and protein crystals that reside deep inside your ear in the vestibule. You’d need a high-powered microscope to see a single otoconium—they’re roughly 10 microns across, or about 0.000393701 inches. Despite their small size, "otoconia create a lot of mischief,” Zee says. “These little stones can get dislodged and kind of float around, producing a powerful false sense of spinning.”

Most of us likely have a few renegade stones floating around in our inner ears, but it’s only when large clumps of more than three or four stones form and get loose that there’s a problem. Why they dislodge and relocate remains a mystery, but in some cases, the stones' movements can be triggered by external motion—a knock on the head or a ride on a bumpy road.


Migraine headaches can bring on the dizzying sensation, as can lying in the magnetic field of an MRI machine. Other causes include labyrinthitis, an infection in the inner ear, and vestibular neuronitis, an infection of the vestibular nerve, which controls balance. Some people have a rare type of chronic peripheral vertigo called Meniere’s disease, which is caused by a buildup of fluid in the inner ear. Often doctors can’t pinpoint a specific cause for an episode of vertigo.


Far less common is central vertigo, which originates in the brain. Symptoms can vary, but a person with central vertigo is often unable to walk due to severe imbalance and may have nystagmus—strange, involuntary eye movements. This type of vertigo can be caused by diseases or injuries to the brain, such as multiple sclerosis, tumors, concussions, or strokes. In some cases, it lasts for weeks or even the rest of someone's life, especially if they have permanent brain damage.


Nearly one-third of people over the age of 40 in the U.S.—roughly 69 million people—will experience vertigo at least once in their lives. It’s much more common in older people, especially those over the age of 60. But anyone can get vertigo, including children (though it may be harder to spot in kids because they can have difficulty describing their symptoms). Professional golfer Jason Day was just 27 when he developed vertigo during the U.S. Open, and basketball player Pau Gasol was in his early thirties when the condition benched him. Some medical historians believe Charles Darwin suffered from vertigo later in life.


Recent research suggests the disparity might be related to bone loss caused by aging, vitamin D deficiency (which impairs how the body metabolizes calcium—a key component of the otoconia’s mineral composition), or the increased frequency of migraine among women.


Because it's so disorienting and comes on so suddenly, vertigo can cause anxiety and panic attacks. Chronic vertigo can cause depression in some people because doing everyday tasks—like caring for themselves, their children, or their family—is often impossible. They might even lose their job because driving is out of the question.


Drug treatments vary, based on the type of vertigo a person has, and generally target the symptoms of vertigo, not the cause. Antiemetics such as meclizine may inhibit the nausea or vomiting that accompanies most types of vertigo. For migraine-associated vertigo, doctors may prescribe beta blockers, anticonvulsants, or antidepressants. People with Meniere's disease may benefit from steroids or non-pharmaceutical approaches, such as a low-salt diet, which reduces fluid retention, or surgical procedures that help drain the inner ear.


The most commonly used therapy for BPPV is the Epley maneuver (also known as a canalith repositioning procedure). Essentially, the exercises are human versions of those ball-in-a-maze puzzles you played as a kid, where you rolled a bead around in a maze, trying to get the bead to go into a hole. The goal is to roll the renegade otoconia (the beads) through the maze of canals inside your ear and return them to the vestibule (the hole). These moves, which take 15 minutes or less, resolve symptoms in about two-thirds or more of people with vertigo—usually after just a few tries.


As you get older, you lose neurons in your inner ears, your brain’s coordination center, and in your feet—a triple whammy of losses that sets up a perfect storm for balance problems, Zee tells Mental Floss. But activities that challenge your sense of balance—like tai chi, yoga, or dancing—help in the long run. You don't get have to be as nimble as Johnny Castle log dancing or blind Frank Slade doing the tango—just get moving to the beat when your favorite songs come on.


In 1982, French climber Alain Robert sustained massive injuries when he took a header from a rocky cliff during one climb—and though he recovered from multiple broken bones, the severe head trauma he sustained left him with chronic vertigo. Despite his condition, Robert returned to climbing (almost always without safety equipment), tackling the Empire State Building, the Eiffel Tower, and a multitude of other tall structures, eventually scaling the Burj Khalifa—the world’s tallest building. He now holds the Guinness World Record for climbing the most buildings.


Named the “greatest film of all time” by the British Film Institute’s Sight and Sound magazine, Vertigo, starring Jimmy Stewart and Kim Novak, is a twisted tale about the human psyche, full of mystery, romance, and suspense—classic Hitchcock. The film is famous for its pioneering use of the dolly zoom—a camera technique sometimes called "the Vertigo effect" that recreates the unsettling experience. Although Hitchcock got the special effects right, the condition that Jimmy Stewart’s character had is not vertigo—it's acrophobia, or fear of heights. When a person with acrophobia looks down from a great height, they might feel vertiginous—but they're not experiencing a vestibular disorder. The reaction may be rooted in humans’ natural fear of falling.

7 Facts About Blood

Moussa81/iStock via Getty Images
Moussa81/iStock via Getty Images

Everyone knows that when you get cut, you bleed—a result of the constant movement of blood through our bodies. But do you know all of the functions the circulatory system actually performs? Here are some surprising facts about human blood—and a few cringe-worthy theories that preceded the modern scientific understanding of this vital fluid.

1. Doctors still use bloodletting and leeches to treat diseases.

Ancient peoples knew the circulatory system was important to overall health. That may be one reason for bloodletting, the practice of cutting people to “cure” everything from cancer to infections to mental illness. For the better part of two millennia, it persisted as one of the most common medical procedures.

Hippocrates believed that illness was caused by an imbalance of four “humors”—blood, phlegm, black bile, and yellow bile. For centuries, doctors believed balance could be restored by removing excess blood, often by bloodletting or leeches. It didn’t always go so well. George Washington, for example, died soon after his physician treated a sore throat with bloodletting and a series of other agonizing procedures.

By the mid-19th century, bloodletting was on its way out, but it hasn’t completely disappeared. Bloodletting is an effective treatment for some rare conditions like hemochromatosis, a hereditary condition causing your body to absorb too much iron.

Leeches have also made a comeback in medicine. We now know that leech saliva contains substances with anti-inflammatory, antibiotic, and anesthetic properties. It also contains hirudin, an enzyme that prevents clotting. It lets more oxygenated blood into the wound, reducing swelling and helping to rebuild tiny blood vessels so that it can heal faster. That’s why leeches are still sometimes used in treating certain circulatory diseases, arthritis, and skin grafting, and helps reattach fingers and toes. (Contrary to popular belief, even the blood-sucking variety of leech is not all that interested in human blood.)

2. Scientists didn't understand how blood circulation worked until the 17th century.

William Harvey, an English physician, is generally credited with discovering and demonstrating the mechanics of circulation, though his work developed out of the cumulative body of research on the subject over centuries.

The prevailing theory in Harvey’s time was that the lungs, not the heart, moved blood through the body. In part by dissecting living animals and studying their still-beating hearts, Harvey was able to describe how the heart pumped blood through the body and how blood returned to the heart. He also showed how valves in veins helped control the flow of blood through the body. Harvey was ridiculed by many of his contemporaries, but his theories were ultimately vindicated.

3. Blood types were discovered in the early 20th century.

Austrian physician Karl Landsteiner discovered different blood groups in 1901, after he noticed that blood mixed from people with different types would clot. His subsequent research classified types A, B and O. (Later research identified an additional type, AB). Blood types are differentiated by the kinds of antigens—molecules that provoke an immune system reaction—that attach to red blood cells.

People with Type A blood have only A antigens attached to their red cells but have B antigens in their plasma. In those with Type B blood, the location of the antigens is reversed. Type O blood has neither A nor B antigens on red cells, but both are present in the plasma. And finally, Type AB has both A and B antigens on red cells but neither in plasma. But wait, there’s more! When a third antigen, called the Rh factor, is present, the blood type is classified as positive. When Rh factor is absent, the blood type is negative.

Scientists still don’t understand why humans have different blood types, but knowing yours is important: Some people have life-threatening reactions if they receive a blood type during a transfusion that doesn’t “mix” with their own. Before researchers developed reliable ways to detect blood types, that tended to turn out badly for people receiving an incompatible human (or animal!) blood transfusion.

4. Blood makes up about 8 percent of our total body weight.

Adult bodies contain about 5 liters (5.3 quarts) of blood. An exception is pregnant women, whose bodies can produce about 50 percent more blood to nourish a fetus.)

Plasma, the liquid portion of blood, accounts for about 3 liters. It carries red and white blood cells and platelets, which deliver oxygen to our cells, fight disease, and repair damaged vessels. These cells are joined by electrolytes, antibodies, vitamins, proteins, and other nutrients required to maintain all the other cells in the body.

5. A healthy red blood cell lasts for roughly 120 days.

Red blood cells contain an important protein called hemoglobin that delivers oxygen to all the other cells in our bodies. It also carries carbon dioxide from those cells back to the lungs.

Red blood cells are produced in bone marrow, but not everyone produces healthy ones. People with sickle cell anemia, a hereditary condition, develop malformed red blood cells that get stuck in blood vessels. These blood cells last about 10 to 20 days, which leads to a chronic shortage of red blood cells, often causing to pain, infection, and organ damage.

6. Blood might play a role in treating Alzheimer's disease.

In 2014, research led by Stanford University scientists found that injecting the plasma of young mice into older mice improved memory and learning. Their findings follow years of experiments in which scientists surgically joined the circulatory systems of old and young mice to test whether young blood could reverse signs of aging. Those results showed rejuvenating effects of a particular blood protein on the organs of older mice.

The Stanford team’s findings that young blood had positive effects on mouse memory and learning sparked intense interest in whether it could eventually lead to new treatments for Alzheimer’s disease and other age-related conditions.

7. The sight of blood can make people faint.

For 3 to 4 percent of people, squeamishness associated with blood, injury, or invasive medical procedures like injections rises to the level of a true phobia called blood injury injection phobia (BII). And most sufferers share a common reaction: fainting.

Most phobias cause an increase in heart rate and blood pressure, and often muscle tension, shakes, and sweating: part of the body’s sympathetic nervous system’s “fight or flight” response. But sufferers of BII experience an added symptom. After initially increasing, their blood pressure and heart rate will abruptly drop.

This reaction is caused by the vagus nerve, which works to keep a steady heart rate, among other things. But the vagus nerve sometimes overdoes it, pushing blood pressure and heart rate too low. (You may have experienced this phenomenon if you’ve ever felt faint while hungry, dehydrated, startled, or standing up too fast.) For people with BII, the vasovagal response can happen at the mere sight or suggestion of blood, needles, or bodily injury, making even a routine medical or dental checkup cause for dread and embarrassment.

9 Surprising Facts About the Scientific Study of Sex

vadimguzhva/iStock via Getty Images
vadimguzhva/iStock via Getty Images

The scientific study of sex is much more exciting than an awkward sex ed class. While writing my book Sex Weird-o-Pedia, these were some of the most interesting facts about science and sex that I came across.

1. Some sex researchers didn't want their findings to get into the wrong hands.

The pioneering sex researcher Richard von Krafft-Ebing didn’t want his knowledge in the hands of ordinary folk. So he wrote Psychopathia Sexualis, the founding document of modern sexology—which was published in Germany in 1886 then translated and published in English in 1939—in Latin to discourage regular Joes (and/or Janes) from reading it.

2. You burn more calories mowing the lawn than you do having sex.

Young woman poses for selfie while mowing the lawn
Alina Rosanova/iStock via Getty Images

Sex might seem strenuous when things get hot and heavy, but it's usually not that great of a workout. You'd have to go at it for nearly 200 minutes to burn as much energy having sex as you do during a 30-minute run. Even mowing the lawn burns about three times more calories than sex. According to the British Heart Foundation, sex burns about the same amount of energy per minute as ironing clothes.

3. A surprising number of mothers claim to be virgins.

In a 2013 study of several thousand pregnant women in the U.S. published by BMJ, about 1 percent of the participants claimed they were virgins when they gave birth. This, of course, calls into question the veracity of studies that rely on self-reported sexual behaviors.

4. Penicillin may have ignited the sexual revolution.

One economist says that penicillin, and not the birth control pill, was the real enabler of the sexual revolution. A study published in the Archives of Sexual Behavior in 2013 shows that penicillin contributed to a 75 percent decline in the number of deaths caused by syphilis from 1947 to 1957. Since the new treatment made sex safer, people started having riskier sex, which resulted in increases in the numbers of children born out of wedlock and teenage pregnancies.

5. Twins can have different dads.

A photo of fraternal twins
Aleksandr Zhurilo/iStock via Getty Images

While it is very rare, it is possible for fraternal twins to have two different fathers. What’s more common is for a rom-com to be based on this scenario.

6. Gender may influence how people handle sexual jealousy.

Research from evolutionary psychologists indicates that people’s gender influences how they react to sexual jealousy. For men, they react more strongly to sexual unfaithfulness than emotional infidelity. For women, it is the reverse. The theory behind these behaviors comes back to evolution: Males who were intolerant toward their wives becoming sexually active with other men were less likely to become an object of derision and more likely to see their own genes pass onto future generations. Women who prevented their husbands from emotionally bonding with other women reduced the chances of the men spending their resources on other women.

7. One of Ivan Pavlov's colleagues created his own (slightly x-rated) conditioning experiment with dogs.

You’re probably aware of Russian researcher Ivan Pavlov and his famous conditioning experiment in which he trained a dog to salivate at the sound of a bell. What you might not know is that one of Pavlov’s American students, W. Horsley Gantt, conditioned dogs to become sexually aroused when they heard specific tones. The experiment, according to Mandy Merck's In Your Face: 9 Sexual Studies, was intended "to study conflicts of the drives between ... experimentally induced anxiety states and sexual excitement."

8. Couples whose first child is a girl are more likely to get divorced.

Parents pay attention to their phones instead of their daughter
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Married couples whose first child is a girl are more likely to get divorced than those whose first child is a boy. Scientists are split as to why this is. One theory is that female embryos are better able to endure maternal stress than male embryos, so pregnant women in unhappy marriages are less likely to have a miscarriage if the child they are bearing is a girl. But once they have a daughter, these couples are more likely to split up since there were already fissures in their relationship prior to the child’s birth.

9. There's a link between pubic hair and STIs.

A downside of pubic grooming is that it might raise STI risk. In a study conducted by a University of Texas scholar, people who regularly shaved their pubic areas contracted STIs about 80 percent more often than those who never shaved down there. One suggestion is that those who regularly shave are more likely to tear their skin, making it easier for viruses to enter the body.

Ross Benes is the author of Sex Weird-o-Pedia: The Ultimate Book of Shocking, Scandalous, and Incredibly Bizarre Sex Facts.