When sparks fly between two people, we're quick to say they have "chemistry." Not everyone realizes that such couples literally have do have chemistry--it's what's behind those sweaty palms, the jumpy stomach, thumping heart, and nervous jitters. Chemistry also contributes to that warm, comfortable feeling you get from being with a longtime partner.
In the mid-1960's, psychologist Dorothy Tennov surveyed 400 people about what it's like to be in love. Many of her respondents talked about fear, shaking, flushing, weakness, and stammering. Indeed, when human beings are attracted to one another, it sets off quite a chain reaction in the body and brain. But there's a perfectly logical explanation to those intense feelings.
The most well-known love-related chemical is phenylethylamine -- or "PEA" -- a naturally occurring trace ammine in the brain. PEA is a natural amphetamine, like the drug, and can cause similar stimulation. This natural upper contributes to that kick-up-your-heels, on-top-of-the-world feeling that attraction can bring, and gives you the energy to stay up all night talking to a new love. Sometimes this energy translates into the triple-espresso jitters; other times it simply keeps you wide-eyed and alert long past the time when you'd usually be yawning. "I always get excited about somebody who can keep me up late at night," says Elan Freydenson of New Jersey. "I really value my sleep."
You can also get a non-romantic dose of PEA from high-intensity activities like skydiving, or by eating chocolate. According to Chocolate.org, chocolate contains small amounts of our love drug, PEA. That might be why some people use chocolate as "comfort food," getting the same warm, relaxed feeling from chocolate as others do from Mom's chicken soup.
One of the substances released by PEA is the neurochemical dopamine. A recent study done at Emory University shows that female voles (small rodents) choose their mates in response to dopamine being released in their brains. When injected with dopamine in a male vole's presence, the female will pick him out of a crowd later. Our love food, chocolate, also elevates levels of dopamine in the brain.
In turn, Dopamine stimulates the production of oxytocin, sometimes known as "the cuddle chemical." Oxytocin is best known for its role in mothering, stimulating contractions during labor and aiding with breast feeding. According to BirthPsychology.com scientists now think that both genders release this nurturing hormone when touching and cuddling, with the oxytocin level peaking during orgasm.
Another euphoria-inducing chemical in your brain, norepinephrine, stimulates the production of adrenaline and makes your blood pressure soar when near the person you're attracted to. That's why you might experience a pounding heart or sweaty palms when you see someone you've got the hots for.
What The Brain Tells the Body
How do our emotions get translated into physical sensations? A U.S. News and World Report article explains the importance of the vagus, a nerve that threads through your whole body. It transports signals from your brain to your organs, "setting the heart pounding, making the stomach do flip-flops, and of course, lighting the loins on fire." Everyone knows that jumpy, sort of sick feeling in your stomach. Some people call it a "hollow" feeling, while Elan Freydenson describes it this way: "That weird feeling falls somewhere between my belly button and my heart. It feels like tension building, yet it feels great and I want to have that feeling more often."
Tennov's group also reported "intrusive thinking," where it seems like your brain is fixated on the object of your affection. When your heart rules your head, there's actually one part of your brain running the other: the cortex is the area of your brain that controls logical thinking, while emotions are processed by the limbic system. When too many happy chemicals like PEA and dopamine flood your brain, they head straight for the limbic system.
When The Honeymoon's Over
Some scientists believe that after a certain period, from 18 months to 4 years, one's body gets used to these love stimulants. After building up a tolerance to uppers like PEA, passionate romances can cool into what Helen Fisher, author of "Anatomy of Love" calls "attachment." In this phase of the relationship, your brain produces endorphins, brain opiates more like morphine than speed. "Unlike PEA," says Fisher, "they calm the mind, kill pain, and reduce anxiety." So what some people call "separation anxiety" might actually be a form of drug withdrawal.
The idea that the "honeymoon period" of a relationship is fueled by different brain chemistry than what is present during the mellower years that come later might explain why some people can't seem to hold long-term relationships: they prefer the revving-up affects of brain amphetamines to the pain-killing effects of endorphins.
"Divorce rates peak around the fourth year of marriage," says Charles Panati in his book "Sexy Origins and Intimate Things." "The initial 'highs' of love have lost their chemical underpinnings Marilyn Monroe's classic film "The Seven Year Itch" should be retitled 'The Four Year Itch."
Lynn Harris, co-creator of BreakupGirl.com wonders if it's the other way around. "Relationships take work. They just do. And people get lazy after a while," she says. "So do they get lazy because they're getting immune to the chemicals, or do they get lazy because they just do...which triggers a decline in the chemicals?"
In the end, even hard-core scientists agree that chemistry isn't everything. Culture, circumstances, personality, and scores of other variables help decide who turns your head and who leaves you cold. So don't try to reproduce that lovin' feeling in a basement chemistry lab--but do try your best to enjoy the natural highs that life gives you.
Find the one who gives you that chemical reaction! Experiment at Match.com.