Surprising Things You Didn't Know about Your Body

1. Your Feet Can Grow as You Age

After years of wear and tear, tendons and ligaments in your feet may weaken. This can cause arches to flatten, which means feet get wider and longer. It won’t happen to everyone, though—people who are overweight, who get swollen feet or ankles, or who have certain medical conditions, like diabetes, are more prone. If it does happen, the average gain is about one shoe size by age 70 or 80.

2. Motion Sickness is Caused by Your Insides Actually Shifting

When a roller coaster comes over its crest, slows for a second for added torture, and then plummets downward, the seat belt keeps your rear in place, but some loosely connected internal organs—like your stomach and intestines—get a little “air time.” You’re not damaging your innards by riding even the craziest of coasters (everything returns to its proper place), but your nerves detect the movement, which registers as though your stomach has jumped into your throat.

3. Women Handle the Cold Worse than Men

The fairer sex has a higher percentage of body fat and conserves more heat around the core. That helps keep vital organs nice and toasty but not the extremities—and when your hands and feet feel cold, so does the rest of your body. Plus, research suggests that women have a lower threshold for cold than men. When exposed to the same freezing temperature, the blood vessels in women’s fingers constrict more than men’s do, which is why they turn white more quickly

4. "Old-person Smell" is Real

But there’s also a distinctive middle-aged-person smell and a young-person smell, according to a recent study. The research found that older people have a less intense—and more pleasant—scent than the middle-aged folk and young whippersnappers. Not what you expected, right?

5. Your Senses Hate Room Temperature Coffee

Temperature affects flavour. Researchers in Belgium found that certain taste bud receptors are most sensitive to food molecules that are at or just above room temperature. So hot coffee may seem less bitter (and, in turn, taste better) because our bitter-detecting taste buds aren’t as sensitive when coffee is hot. Odours influence flavour as well, so even the most bitter hot coffee may taste delicious because of its pleasant aroma; room-temperature coffee doesn’t smell the same.

6. You Can Urinate at Night, but That's Usually It

The sophisticated, intelligent neurons in your gut that control colon contractions, which push out waste, are also influenced by your body’s circadian rhythm, the internal clock that wakes you when it’s light out and makes you feel sleepy at night. So most people don’t have the urge to empty their colon in the middle of the night.

On the other hand, the bladder, which acts a reservoir for the continuous flow of urine produced in the kidneys, can stretch only up to a certain volume before you gotta go. Normally, you can sleep six to eight hours without having to urinate, but certain medical conditions or drinking too much water before bed can wake you to use the bathroom at night.

7. Fingerprints Don't Actually Improve Your Grip

Many experts think we have fingerprints to improve grip, but a British study from a few years back suggests otherwise. Researchers found that a fingerprint’s ridges actually made it harder to hold flat, smooth surfaces, like Plexiglas, because they reduced the skin’s contact area. Instead, they think our prints might help wick water off our fingertips or allow our skin to stretch more easily, which can protect it from damage and help prevent blisters. Other scientists have suggested fingerprints could improve our sense of touch.

8. Achy Joints May be Able to Forecast the Weather

A change in barometric readings may be part of the reason: Atmospheric pressure often drops right before bad weather sets in; this shift could cause body tissue to expand, which can lead to swelling and pain. The effect is slight, but people who have arthritic or inflamed joints may detect the difference. Temperature may have an impact too: In 2007, researchers at Tufts University found that every ten-degree drop in temperature corresponded with a small increase in osteoarthritic knee pain.

9. Holding Your Breath Can Help Stop Hiccups

It’s thought that if you build up carbon dioxide in your body (by not exhaling), it will help stop your diaphragm from spasming, which is what causes the hiccups. When your diaphragm contracts involuntarily, it forces a quick intake of breath that’s suddenly stopped by the epiglottis—a flap of cartilage located in the throat behind the tongue. That closure is what causes the hiccup sound.

10. Your Teeth Shift with Age, Even if You Had Braces as a Teen

Every smile is different, but a lot of this has to do with loss of the bone behind the gums that occurs with aging. If you lose enough bone—which can be exacerbated by such factors as smoking or gum disease—your teeth can shift.

11. Your Growling Stomach is Actually Begging for Food

The sound of your digestive juices churning and stomach muscles contracting as they get prepped for food is usually what you're hearing. To avoid those often poorly timed and embarrassing sounds, eat smaller meals more frequently.

12. Your Diaphragm Causes Side Stitches When You Run

Your diaphragm gets stretched, pulled, and pounded during a run, which can cause that sharp, stabbing pain at the lower edge of your rib cage, usually on the right side of your body. To help the pain pass, slow down and take more controlled, easy breaths.

13. Bacteria is What Makes Your Pits Stink

Your body has two kinds of sweat glands. Most of those on your arms and legs secrete a mix of water and salt. But the glands in your armpits (as well as your groin) release an oily substance, which bacteria love. It’s actually the bacteria eating the oil that releases the telltale stench.