Although we aren’t sure how kissing got started (it is a little strange when you think about it), the science behind smooching is interesting. Check out 10 things you probably didn’t know about kissing.

Whether you cringe when a kissing scene pops up in a movie or swoon as the couple locks lips, everyone is a little curious about kissing. Discover these amazing, and somewhat disturbing, things you probably didn’t know about kissing.

1. Like it or not, you’re addicted.

When you kiss someone, you get a spike in the neurotransmitter dopamine, one of the chemical signals that pass information from one neuron to the next – and the same one that gives you an adrenaline rush. This makes you want to kiss again (and again…and again). Dopamine energizes the brain, possibly making you lose your appetite or make it hard for you to sleep. Sheril Kirshenbaum, author of The Science of Kissing, tells Shape, “The more anticipation you feel leading up to a kiss, the greater the dopamine spike.”

things you probably didn't know about kissing2. A lot of bacteria is shared – but that’s a good thing!

Of all the things you probably didn’t know about kissing, this is one fact you probably don’t want to know. According to a study published in the journal Microbiome, a 10-second French kiss can spread 80 million bacteria between mouths. It sounds kind of gross, but swapping spit can actually act as a form of immunization, allowing you to build up resistance from exposing yourself to more microorganisms. Kiss away, and you might find yourself getting sick less often!

3. It’s a workout (of sorts).

Believe it or not, you’re using plenty of muscle when you pucker up.The muscle you use to pucker your lips is called the “orbicularis oris.” Simple pecks use as few as two muscles, but French kissing puts as many as 23 to 34 facial muscles and 112 postural muscles to work. And like any workout, you’re burning calories! Kissing burns between five and 26 calories per minute.

things you probably didn't know about kissing

Photo Credit: Flickr Creative Commons

4. The longest kiss lasted over two days.

This might be one of the strangest things you didn’t know about kissing: A couple in Thailand currently holds the world record for the longest kiss. Ekkachai and Laksana Tiranarat locked lips for 58 hours, 35 minutes, and 58 seconds. The worst part? They couldn’t sleep for the full two-and-a-half days for the kiss to count! Now that is some serious dedication to kissing. Do you think you have what it takes to break the record? Wait – how did they go to the bathroom? Maybe some records aren’t made to be broken…

5. The “X” in “XOXO” goes back to the Middle Ages.

Everyone knows “X” means kiss and “O” means hug, but one thing most of you probably didn’t know about kissing is the origin of this shorthand. Historians trace the origin of X and O back to the Middle Ages when most people didn’t know how to read or write. Peasants used to mark “X” as a stand-in signature then kissed the document.

6. The average person spends two weeks of his or her life kissing.

Be sure to schedule this in!

Experts estimate that the average person will spend 20,160 minutes of his or her life kissing. FYI, that’s two full weeks of your life locking lips!

things you probably didn't know about kissing7. Humans aren’t the only animals that kiss.

Plenty of other animals show affection to each other, and some do it in a way very similar to humans. Chimpanzees sometimes kiss after a fight – just like we “kiss and make up.” Studies have shown that this type of behavior isn’t confined only to chimpanzees — many other primates “kiss” in some form. Cows, puffins, squirrels, and even snails also kiss!

8. Two thirds of people tilt their head to the right when they kiss.

A German researcher figured this out when he observed over 100 couples and noted that the majority were tilting the same way. Experts believe the instinct to tilt your head to the right during a smooch originates from the womb, when we naturally tilted our heads to the right.

9. The study of kissing is called philematology.

The term comes from ancient Greek, where the world philos means “earthly love.”

things you probably didn't know about kissing10. Kissing can help you live longer.

This is one of the most surprising things you probably didn’t know about kissing. Studies show that men live up to five years longer if they kiss their wife before going to work. Because they start their day on a positive note, they’re also less likely to get into an accident or to miss work because they’re sick.

Who knew that kissing had health benefits, burns calories, and takes up so much of our lives? Essentially, kissing is good for you and makes you feel good. Want to know more about the physiology of love? Check out the science of having a crush!

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