Did you know that it’s literally possible to smell fear? Scientists have discovered that the scent of our body changes before we do something scary, even if we’re trying to seem brave, and other people can literally smell the difference.
Scientists have unraveled many amazing mysteries about the body, including a secret our earlobes reveal about our heart health, and why a 3-second yawn revs up our brain and even improves our mood.
Here are seven weird body facts, some of which seem too strange to be true—but are.
1. Your heart health is predicted by your earlobes
Oddly enough, a diagonal crease – or lack of crease — in your earlobe may determine the health of your heart. Although scientists are exploring the reason behind the link, a 1992 study of hospital patients was the first to report that those with an earlobe crease were far more likely to have coronary artery disease (CAD).
In fact, this indicator was 94 percent accurate at predicting which patients had CAD, prompting the researchers to suggest that this weird clue be used to help identify at- risk patients. More recent research also linked earlobe lines to risk for sudden cardiac death in men.
2. Yawning is contagious, but less so in the summer
Seeing other people yawning—even in photos—can make you yawn in response. However, a 2011 study with 80 participants per season showed that yawning in response to photos only happened 24 percent of the time in the summer, versus 45 percent of the time in the winter.
Apparently, yawning cools down your brain a bit, so outside temperature makes a big difference in how likely you are to catch the urge. Scientists also report that yawning also helps keep us alert, because. It turns out that difficult mental tasks literally heat up the brain, while a yawn lowers the temperature.
Another surprising research finding: You can’t complete a yawn with your eyes open, reports neuroscientist Robert Provine in his new book, Curious Behavior: Yawning, Laughing, Hiccupping and Beyond).
3. The body’s largest organ is the size of six tennis courts, yet is only one cell thick
The endothelium, the smooth interior lining of the more than 60,000 miles of blood vessels in the body, would cover six tennis courts if removed from the body and flattened. It’s been called “the brain of the arteries,” because it acts as a smart barrier to control which substances can pass from the blood into the arterial wall.
The endothelium also makes “executive decisions” by releasing molecules that help regulate blood pressure, fight off disease, control blood clotting, and fine-tune blood so it remains fluid enough to flow easily.
4. Hearing words and seeing colors
In most people, taste, sound, and vision are distinctly separate, but those with a rare condition called synesthesia have a blurring of sensory experiences. Some actually experience tastes in response to words, while others hear sounds when they see certain colors.
“The proportion of words that triggers taste varies…for those in our study it ranged from about 15 percent of words, to one lady who experiences tastes for 100 percent of words,” researcher Julia Simner told WebMD. Scientists are still working to understand how synesthesia affects the brain.
5. You can literally smell fear
People can actually detect and respond to fear by smelling people’s sweat. Research funded by the U.S. Defense Advanced Research Projects Agency shows that there are different pheromones (detectable chemical substances) from armpit odor when people are afraid than when they aren’t. Their fear can literally be picked up from their body odor.
Researchers taped absorbent pads to 20 people’s armpits right after they ran on a treadmill, and again right before they were about to take a tandem jump while skydiving for the first time. Volunteers were then able to differentiate between the two types of sweat, and areas of their brain that react to fear were more active when they smelled the skydiving sweat than the treadmill sweat.
6. The scent of women’s tears reduces men’s sexual arousal
A 2011 study published in Science magazine showed that tears act as a chemosignal, or a chemical substance detectable by others. Not only did men who sniffed tears (which were brought on by negative emotions) find photographs of women’s faces less attractive, the men also reported that they were less sexually aroused, and the scientific data backed it up.
The men’s physiological measures of arousal were reduced, levels of testosterone lowered, and they had reduced activity in the substrates of their brain that are linked to sexual arousal.
7. It’s practically impossible to keep your eyes open when you sneeze
A common misconception is that we shut our eyes to avoid the spray of airborne droplets. Actually, a simple reflex prompts our peepers to blink shut during a sneeze, similar to the reflex that occurs when the doctor taps your knee with a medical mallet, allergists report.
While you can try to keep your eyes open when you sneeze, it’s extremely difficult to do. And since the spray you release can carry germs, it’s also common courtesy to cover your mouth and not infect others.
