Valentine's Day is around the corner. But before you chalk it up to a greeting card holiday, consider this: There's actually some real science behind those feelings of romance and affection.
Researchers from around the U.S. conducted several small studies, presented at a meeting of the Society for Personality and Social Psychology, examining the interactions between love and stress and love and infidelity, as well as the cost-benefit analysis that goes into saying "I love you."
In one of the studies, researchers looked at 34 couples who lived together and tested for the stress hormone cortisol before, during and after being separated for four to seven days. Researchers found that when the couples were separated physically, they had higher cortisol levels and had worse sleep than when they were together.
"During separations, only lengthy phone calls appeared to 'stand in' for contact," study researcher Lisa Diamond, of the University of Utah, said in a statement. "The findings can contribute to our emerging understanding of the processes through which longstanding romantic ties are beneficial for our health."
Researchers also found that love brings out the competitive side of people. Florida State University researchers found that the stronger the feelings of romantic love toward a partner, the more likely a person was to engage in aggressive and belittling behavior toward a possible attractive rival.
In addition, researchers from the MIT Sloan School of Management found that the timing of saying "I love you" for the first time to a partner is based on cost-benefit analysis. They also found that men are more likely to say "I love you" first.
"When and why we express romantic love are guided by deep-seated motivations that are best understood in an economic framework. Love confessions are akin to economic resources that people use to negotiate evolved romantic interests," study researcher Josh Ackerman, of MIT, said in a statement. His study first appeared in the Journal of Personality and Social Psychology last year.
Past research on love and health also presented benefits. ABC News reported on a study showing that being with a spouse or partner is linked with a drop in blood pressure.
Another study showed a link between being in an intimate relationship and a longer life, ABC News reported.