Could it be?
Your heart beats faster. You can hear your blood pulsing in your veins. Every time he even looks at you, you feel a burst of energy. Could it be? Are you in love?
That our bodies send us signals that tell us "this guy could be a keeper," is no big surprise. But how does this work exactly? Is it something we do subconsciously? Do our brains and bodies really tell us when we're in love?
We asked a couple of scientists to sound in—here they've given us five physical signs you're in love:
1. You Catch Yourself Staring
"What's that song…'it's in his eyes'?" asks Dr. Lucy Brown, neuroscientist and professor at the Albert Einstein College of Medicine. "I don't think that's the title, but that's what it should be."
Dr. Brown, who has studied neural basis of emotion, says the eyes are what matters most. When you're in love, you involuntarily cannot keep your eyes off of the object of your affection. Humans naturally find eye contact rewarding. Not only that, but we're physically compelled to pursue eye contact with our romantic interests.
"One of the involuntary manifestations of being in love is 'mooning around' the person, having your eyes constantly fixed on a person," says Dr. Brown.
2. You Feel High
When you realize you've been hyperactively talking about your new beau, you might think you've had too much caffeine. It's actually a different drug.
"Being in love is like being high on cocaine," according to Dr. Brown.
Many of the physical symptoms are the same: increased energy, increased heart rate and blood pressure (especially when you see the person), and the inability to sleep or eat are just a few. Feelings of euphoria also appear with cocaine use, as they do when in love.
These symptoms occur because, while the brain produces dopamine on its own, it produces even more when in love. The brain also produces more of the chemical norepinephrine when we're in love, speeding up the heart when we're nervous, as we might be upon seeing our beloved.
"Part of your nervous system is saying 'this is very important to me,'" says Dr. Brown, so the nervousness (the culprit behind those telltale sweaty palms) is natural.
Some psychologists actually regard love as an addiction instead of an emotion because it causes these aforementioned behaviors and because it is a "goal-oriented motivational state" like addiction. Love also activates the subcortical and cortical areas of the brain associated with drug cravings.
3. You Can't Keep Your Hands Off Each Other
You won't just be seeking your beau visually. Just as you hunt down food when hungry, you'll actively engage in proximity-seeking behavior when you're in love.
This explains why grade-school flirtation often involves pushing or hair-pulling. When in love, we can't resist the urge touch our beloved (luckily, we learn how to do this in more polite and pleasing manners later in life).
Dr. Bianca Acevedo, Visiting Scientist at the State University of New York at Stony Brook, says when we're in love, our bodies will subconsciously lean toward each other, a physical manifestation of the brain's desire for emotional closeness. Have you caught yourself wiggling closer to your lover?
4. You Can't Stop Thinking About Him...
With the increased dopamine levels of romantic love, people think about their romantic interests, on average, 85 percent of the day. This is known as "intrusive thinking."
According to Dr. Brown, "In the early stages of romantic love, most people can't stop thinking about their beloved. The other person becomes an obsession," and will occupy their thoughts for what may seem like an extreme amount of time. But it's really quite normal. In fact, Brown says "If it is less than 40 percent, then it is not really intense romantic love."
The level of obsession, while normal if in love, is often compared to that of obsessive-compulsive disorder. When patients undergo treatment for OCD, they're provided with serotonin reuptake inhibitors to ease their obsessions. Because of this, scientists figure that the decrease in the brain's normal serotonin levels causes similar behaviors when in love.
4. ...And Only Him
According to Dr. Brown, when we seek a mate with romantic love in mind, we'd prefer a long-lasting relationship. This means we have strong feelings of romantic love for just one person.
Conversely, feelings of lust are less about a specific person than they are for sex itself. When it comes to lust, the preferred relationship could be significantly shorter.
According to a 2002 study in which Brown participated, if a person is really "in love" with his or her partner, desire for emotional union will take precedence over desire for sex. The study also concluded that we seek sexual exclusivity with this one person because we innately hope for uninterrupted courtship and reproduction.
"Love is a survival system, like being hungry or being thirsty," Dr. Brown says. Our bodies seek love (with the goal of reproducing) just as they seek out food or water. Therefore, love for one person is more like a reflex.
Writer's Note: While people won't die without love, as they would without food or water, Dr. Brown says studies have shown that people in relationships live longer; they're also usually healthier and have a greater sense of well-being. The love of friends and family is also important and can even occasionally substitute for romantic love. However, the kind of love we seek depends very much on our hormonal status, what our bodies need at a certain moment in time.
But remember, it doesn't last forever.
Unfortunately (or fortunately, depending on how you look at it), the heightened emotions and general euphoria brought on by romantic love eventually fade.
"You can't keep it up forever or you'll never get anything done!" laughs Dr. Brown. "It's too intense to last. Even the most intense [romantic love] doesn't last more than six months."
But don't worry. As feelings of intense romantic love wane, feelings of attachment develop and that's what keeps people together for the long run.
"You can have just 'attachment' but it's better for the [couple] if there's romantic love [at the start]. People stay together because they remember the warm, positive feelings of having that original, romantic love." This way, couples won't just "stay together for the kids"; they will stay together for each other. That attachment is then transferred to their offspring.
So love itself doesn't necessarily diminish. It just evolves.
Despite all the signs and science, though, if you're in love, you're in love. Even Dr. Brown agrees: "You know when it happens."