40 Crazy Health Facts You Won't Believe You Never Knew

It's time to parse through the fads and the fallacies.

Woman running in sunshine

With the sheer number of trendy diets and sketchy health gurus out there, it can be hard to trust the information you hear about your physical and mental well-being. But by turning to hard research and data, you can clarify what's legitimate and what's nonsense. Here are 40 tidbits about your body and your brain that fit into the former category. From the surprising sense heightened by anxiety to the secrets your skin is revealing, these truly astonishing health facts, all of which are backed by science, will blow your mind.

Urinating in a pool is dangerous for your heart.

two little girls having fun in the pool health facts

Though definitely gross, peeing in a pool may have seemed harmless enough. After all, urine is sterile, as is chlorine, right?

But it turns out, urine and chlorine create dangerous chemicals when combined. In fact, Dr. Xing-Fang Li of the University of Alberta—who conducted research on the topic published in the journal Environmental Science & Technology Letters—told NPR that that so-called "pool smell" is actually the smell of those chemicals. One of which, cyanogen chloride, is classified as a chemical warfare agent and can damage your heart and lungs. Other byproducts, called nitrosamines, can even cause cancer.

Stress heightens allergies.

why we sneeze

Just like chlorine and urine, stress and allergies do not mix well. Not only do allergies increase stress levels, but also stress can make allergies worse. This is because stress has a twofold effect on the body, according to Harvard Medical School. The first is psychological: When you're stressed, things just seem worse than they actually are—allergies included. The second is physical: By ramping up the body's defense responses, stress exhausts them to the degree that core bodily functions, like the ability to fight off allergens, lose efficacy.

Men are more forgetful than women.

forgetful man health facts

Though researchers still don't know why, plenty of studies dedicated to comparing the memory abilities of men and women consistently prove it to be true. According to one hypothesis found in a 2014 study published in The Quarterly Journal of Experimental Psychology, the difference could be due to varying brain structures, specifically that hippocampus in men (the part of the brain associated with memory) begins to decrease in volume faster than it does in women.

Anxiety can make bad smells even worse.

Young Asian woman holding her nose because of a bad smell on pink background health facts

We all know that anxiety can make simple tasks harder, but did you know it affects your perception of smell, as well?

A 2013 study published in The Journal of Neuroscience examined the effect of certain emotions on smell. After exposing subjects to anxiety-inducing images—like car accidents, war, and other horrible things—researchers found that subjects interpreted scents that they'd previously considered neutral as unpleasant and smells that were already considered bad were much worse.

Big eyes tend to be more nearsighted.

Woman with Green Eyes health facts

Big eyes, meaning eyes that are longer from the front (cornea) to the back (retina), are more prone to nearsightedness. Also known as myopia, this condition that causes distant objects to look blurry is caused by light not properly reaching the retina. If your eyeball is particularly long, light is focused too soon before it hits the retina—and by the time it does reach the retina, the image is blurry, according to the National Eye Institute.

Coffee can ward off depression.

man holding coffee smiling health facts

Good news, coffee lovers: Caffeine might actually be helping you ward off depression. A 2016 meta-study on the relationship between coffee and depression published in the Australian and New Zealand Journal of Psychiatry found that each cup of caffeinated coffee consumed per day decreases someone's risk of becoming depressed by 8 percent.

Eating eggs improves your reflexes.

egg carton health facts

Eggs contain an amino acid called tyrosine, which the body synthesizes into norepinephrine and dopamine, compounds that increase energy, alertness, and improve mood. In a 2014 study published in the journal Neuropsychologia, researchers found that tyrosine enhances our ability to respond faster to stopping an unwanted activity.

Consuming hot liquids can cool you down.

cup of hot tea health facts

It may sound counterintuitive, but drinking hot tea or coffee can actually help cool you down on a hot day. You may not feel it at first sip, because, naturally, the heat from the hot liquids will raise your body temperature. But once you start sweating, you'll begin to feel the effects. That's because of increased perspiration, according to a 2012 study from the University of Ottawa published in the journal Acta Physiologica. As your sweat evaporates, you'll wind up feeling cooler than you were at the start.

"What we found is that when you ingest a hot drink, you actually have a disproportionate increase in the amount that you sweat," one of the study's authors, Ollie Jay, a researcher at the University of Ottawa's School of Human Kinetics, told Smithsonian Magazine. "Yes, the hot drink is hotter than your body temperature, so you are adding heat to the body, but the amount that you increase your sweating by—if that can all evaporate—more than compensates for the added heat to the body from the fluid."

Red meat makes body odor worse.

red meat health facts

Carnivores, beware. A 2006 study published in the journal Chemical Senses on how diet affects body odor found that consuming meat can have a huge effect on the "attractiveness" of our body odor.

Though diet is not the only factor that affects natural body odor, those who refrain from eating red meat were generally judged as smelling more pleasant, less intense, and more attractive overall.

The scent of apples can prevent claustrophobia.

apples health facts

An apple a day can keep your claustrophobia away. According to Dr. Alan Hirsch of the Smell & Taste Treatment and Research Center in Chicago, smelling a green apple can change your perception of space, making spaces feel larger than they really are. Hirsch conducted a 1995 study on the subject, which also found that cucumbers have a similar effect and that the smell of barbecue smoke has an opposite effect.

More than half of your bones are in your hands and feet.

Hands of an old man on the wood table.vintage tone health facts

There are 206 bones in the human body. With 27 bones in each hand and 26 bones in each foot, these skeletal structures are the most complex, amounting to 106 bones total between all four limbs, according to the BBC.

Massaging your scars will help them fade.

woman with scar Body Flaws health facts

Most drugstores have over-the-counter creams and oils that are made to fade scars, but there's another remedy that doesn't cost anything. Simply massaging or rubbing scarred areas a couple of times a day can prevent excess collagen buildup, which is what makes scars thick and ropy.

Brett Sears, PT, Cert. MDT suggests using "one or two fingers to massage your scar in a direction that is perpendicular to the line of the scar," he wrote for Verywell Health. "This technique helps to remodel the scar and ensures that the collagen fibers of the scar are aligned properly."

Basking in the morning sun helps with weight loss.

woman meditating at sunset health facts

Spending your mornings in the sun should be the first step to your weight loss plan. A 2014 study published in the journal PLoS One found that exposure to morning sunlight has a positive effect on body mass index (BMI). Just 20 to 30 minutes of natural light—even on a not-so-sunny day—is enough to impact BMI. That's because, without sufficient light, the body may have trouble regulating metabolism, which can eventually cause weight gain.

Ginger can help reduce cramps.

ginger supplement health facts

Ginger has been used as a remedy for ages, dating back an estimated 5,000 years when people from China and India used ginger root to treat indigestion. Because it naturally relieves inflammation, ginger can relieve bloating and gas pains. According to 2015 research published in the journal Pain Medicine, ginger can also help treat menstrual cramps.

It's better to exercise after eating.

woman and man running together

It's long been said that you should exercise on an empty stomach, because your body will not be so tired from digesting, and therefore is able to send more oxygen to your muscles, ultimately promoting fat loss.

However, your body needs the energy you get from food to perform, especially when it comes to intense exercise (and triply so when it comes to heavy lifting). According to a 2018 meta-analysis published in the Scandinavian Journal of Medicine & Science in Sports, 54 percent of studies reported better performance in long-duration aerobic exercise when food was consumed beforehand.

And exercising when you're young slows bone deterioration in old age.

Mom helping her son put on a helmet health facts

Exercising is crucial to healthy body function at all ages, but is especially important for development during your youth. In fact, science has found that being active as a child and young adult can help you stay stronger later in life.

As children are developing, regular exercise can fortify bones, making them stronger, thicker, and ultimately more durable and ready to face the wear-and-tear that comes with age, according to a 2014 study published in the Scandinavian Journal of Medicine & Science in Sports. Because osteoporosis and the loss of bone mass happens to all of us as we mature, a history of exercise can ensure that you stay stronger for longer.

You can tell if someone has high cholesterol based on their skin.

Close up of eyelid xanthelasma during eye examination health facts

We all know high cholesterol can lead to life-threatening conditions like heart attack and heart disease. But you might not have known that high cholesterol can manifest itself on your skin. According to Harvard Medical School, uneven yellow patches called xanthelasma can appear on the eyelid and around the eyes as a result of overproduction of cholesterol, the waxy yellow substance that fills these lesions.

An antihistamine before bed can prevent under-eye circles.

Pink antihistamine tablets in blister pack health facts

Generally, dark circles under your eyes can be avoided if you eat well, sleep well, and drink a lot of water. But many people don't realize that another very common cause of under-eye bags is allergies, according to the Mayo Clinic.

Seasonal irritants—along with bedroom irritants, like dust—may be the root of the problem, so you should try taking an antihistamine before bed. And because anti-allergy medication often causes drowsiness, you'll nod off to sleep faster as a bonus.

Saying "thank you" measurably improves your mood.

two women hugging health facts

According to a 2003 study published in the Journal of Personality and Social Psychology, expressing gratitude may be the key to happiness. Researchers reported that in being thankful, you recognize the goodness in your life, which is crucial in overcoming depression. In fact, in their 2007 follow-up book on the subject, Thanks!: How the New Science of Gratitude Can Make You Happier, the researchers found that "regular grateful thinking can increase happiness by as much as 25 percent."

Sounds like it's time to start writing thank you notes, thanking friends, maintaining a gratitude journal, and counting your blessings.

The smell of sage can mitigate stress and anxiety.

sage health facts

Aromatherapy is one of the oldest forms of medicine; it's been practiced for centuries. For example, lavender is known to soothe the mind and is regularly used to promote good sleep.

But sage is just as useful. In 2016, researchers from the University of Montana found that sage can influence neurotransmitters in the brain and activate dopamine pathways, which mitigate feelings of stress and anxiety.

Green tea improves your memory.

green tea health facts

Green tea is kind of like a magic potion. It can help battle anxiety, promote weight loss, stop the growth of cancer cells, and even enhance your memory. In a 2014 study published in the journal Psychopharmacology, researchers at the University of Basel found that consuming green tea activates a link between the frontal and parietal lobes of the brain, which heightens our ability to remember sensory information and language.

Physically active pregnant women have smarter babies.

pregnant woman getting a doctor checkup health facts

Intelligence is somewhat hereditary, but, if you want to better your chances of having a smart child, staying fit and active might help. A 2013 study published in the Journal of Clinical and Experimental Neuropsychology found that pregnant women who exercised just 20 minutes a day, three times a week, improved newborns' brain function.

Reading a tangible book promotes better comprehension than reading on a screen.

dad reading to son
Shutterstock/George Rudy

If you're going to read, put down your Kindle or phone and pick up an actual book. A 2016 study from Dartmouth College followed students who did their reading from actual paper versus those who read from a tablet or laptop. The researchers found that abstract concepts were easier to understand when read on paper. Students using only screens to learn had a much harder time grasping complex ideas.

Optimism promotes longevity.

older woman with pixie cut, look better after 40

According to a 2019 study published in the American Journal of Preventive Medicine, having a positive outlook on life can lead to a longer lifespan. The study found that "optimistic women had a 23 percent greater likelihood of healthy aging."

Optimistic people tend to practice more healthy behaviors, such as eating well, exercising more often, and getting better sleep. These practices, in turn, make them less likely to develop cancer, heart disease, or respiratory disease, all of which are leading causes of death in Americans.

Bananas can boost your mood.

bananas health facts

The next time you're feeling sad and reach for the French fries, try a banana instead. Not only are bananas a healthy snack, but they're also a happy snack, containing 50 times as much dopamine as potatoes, according to 2000 research published in the Journal of Agricultural and Food Chemistry.

And they can minimize bloating.

banana slices health facts

Eating a banana can also help reduce bloating quickly, thanks to its high potassium content, according to a 2018 study published in PLoS One. Potassium helps regulate water and sodium levels in the body to ease digestion. Bananas are also high in fiber, a nutrient that speeds up the digestive process.

Oatmeal helps fight depression.

oatmeal health facts

People experiencing depression and insomnia (or both, as they're often linked) are experiencing a lack of serotonin, the mood-regulating hormone, which is synthesized from the amino acid tryptophan. According to a 2016 study published in the journal Nutrients, eating foods high in tryptophan—like oatmeal—can help regulate mood and sleep.

Eating chocolate makes your skin glow.

chocolate health facts

Chocolate doesn't need to be an indulgence—think of it as a skin treatment instead! According to a 2014 study published in the Nutrition Journal, dark chocolate—which contains at least 70 percent cocoa—has many beauty benefits, including the ability to shield your skin against sun damage and prevent wrinkles. Antioxidants in dark chocolate protect the collagen in your skin, keeping it supple and glowing for longer; they even encourage the body to replace lost moisture in the skin.

And people who eat chocolate on a near-daily basis are thinner than those who don't.

Older Woman Eating a Bar of Chocolate, smart person habits

Chocolate lovers, rejoice! As if treating your skin wasn't enough of an excuse to eat chocolate daily, a 2012 obesity study published in the JAMA Internal Medicine journal found that people who consumed chocolate more often tended to be thinner. The results were consistent, regardless of type of chocolate. Those who ate any kind of chocolate at least five times a week are statistically thinner than the rest. Whoo-hoo!

Chewing gum sharpens your focus.

bubblegum bubble, state world records

Picture a baseball player in the outfield. He's standing there, eyes wide, mitt at the ready. He's also probably chewing. Whether it's tobacco, sunflower seeds, or gum, there's a reason baseball players chew. It's to stay alert—and it's a tactic you can use in your everyday life.

One 2012 study published in the journal Nutritional Neuroscience found that, when chewing gum, people become both more alert. That's because the act of chewing arouses the brain, which associates chewing with nutrients, expects food, and primes itself to be at maximum levels of alertness.

Owning a dog can lower your risk of heart disease.

man walking a dog health facts

High levels of stress over a lifetime are a leading cause of heart disease later in life. And you know what helps decrease stress? Having a dog! According to Harvard Medical School, dog owners have lower blood pressure and lower cholesterol and triglyceride levels, which decrease your risk of cardiovascular disease. So, if your life is impacted by stress, you might want to consider adopting a canine friend soon.

Procrastination and impulsivity are inherited behaviors.

Frustrated Woman on Smartphone health facts

If you find yourself constantly putting off your responsibilities, you can thank your parents. Yep, procrastination may seem like a developed trait, but it turns out that it's actually inherited.

A 2014 study published in the journal Psychological Science found that the same genes that can lead to procrastination also cause impulsivity, which makes sense when you think of how impulsive behavior is the driving force behind procrastination. ("I could do that, but right this very minute, I feel like doing something else.") And these two traits, according to the researchers, are inherited from your ancestors.

Cold temperatures help you fall asleep.

older woman sleeping, subtle symptoms of serious disease

The cold weather may usher in the flu, but there are ways in which cold temperatures are actually good for your health. For example, cool temperatures help you sleep, leaving you feeling more rested and less prone to stress.

According to the National Sleep Foundation, "your body temperature decreases to initiate sleep." So if you keep your room cooler, you're giving your body a jump start.

Taking pictures messes with your memory.

Blur portrait of blissful young people posing with balloons at birthday party with hands holding phone on foreground health facts

The next time you're on vacation, put down the camera and cherish the moment. Otherwise, you're likely to forget it.

One 2018 study published in the Journal of Applied Research in Memory and Cognition tested the effects of photo-taking on memory by asking students to remember a series of 50 paintings in three situations: with no camera, with a camera, and with a Snapchat-like app where photos disappear. Researchers found that those who took pictures always had a harder time remembering photos, with those who used the temporary photo app performing worst.

Spending time in nature makes you happier.

walking is the best exercise

Spending time in nature—whether that means hiking through the forest or simply taking a walk in the park—has been proven to make people happier.

In a 2012 study published in the journal Environment and Behavior that examined the effect of "nature relatedness" on happiness, researchers found that those who rated their lives to be more connected with nature had a better overall quality of life than those who didn't, especially concerning mental health.

Laughing is good for your heart health.

friends laughing health facts

Next time you watch a funny movie, feel free to pass it off as exercise: Research published in the journal Medical Hypotheses in 2009 found that laughing can increase blood flow by up to 20 percent. When you laugh, the outer lining of your blood vessels, called the endothelium, expands and contracts, pumping blood through your body at a faster rate. Higher blood flow is like a workout for the heart, improving its health and strengthening blood vessels.

Heels help you make better choices.

woman shopping in heels health facts

A 2013 study published in the Journal of Marketing Research found that people shopping with heels on had a heightened sense of balance and thereby made better choices when it comes to spending.

With balance on the brain, shoppers were more likely to avoid extreme purchases, products at extremely high and low prices, and opt instead for average-priced products. This is called the equilibrium effect (and it holds true for those who shop immediately following a yoga class as well).

Learning a new language increases brain function.

deaf crazy facts

There are tons of reasons to learn a new language: business, travel, or the simple fact that it's fun and challenging. And now, you can add "brain improvement" to that list.

Much research has been conducted to examine the effects of learning a new language on the brain, and it's consistently been proven that—no matter what age you are—learning a new language increases brain function. In fact, according to one 2012 study published in the Brain and Language journal, it improves memory, concentration, alertness, and even intelligence.

Foods that start with the letter "A" boost sex drive.

Vegan vegetable Buddha bowl with avocado, tomato, rice, arugula and almonds on the wooden rustic table, top view health facts

Arugula, avocado, and almonds, or "the three As," are all wonder-foods for your sex life. Almonds and avocados increase blood flow to sexual organs, and arugula is rich in vitamins A and C, which help promote sex hormone production. If ever there were a perfect date food, it would be a salad out of this stuff!

Good relationships can increase your lifespan.

better parent over 40 health facts

It's no surprise that having close relationships—a supportive partner, a tight group of friends, or a number of attentive family members—has a strong impact on mental health, including higher self-esteem and lower levels of depression. But that, in turn, affects your physical well-being, too. According to a 2016 study published in the journal Proceedings of the National Academy of Sciences of the United States of America, a lack of social connections increases the odds of death by at least 50 percent. And for more ways your loved ones impact your life, here are 15 Surprising Ways Your Partner Impacts Your Health.

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