Love may make the world go ’round, but is it powerful enough to lower one’s blood pressure, reduce depression and speed the healing of an injury? With Valentine’s Day just around the corner, we set out to find the answer and discovered that science says yes.

“Our relationships help us cope with stress, so if we have someone we can turn to for emotional support or advice, that can buffer the negative effects of stress,” says Julianne Holt-Lunstad, an associate professor of psychology at Brigham Young University, who has been publishing studies for the past 10 years on social relationships and their influence on health and disease.

Most studies on the health benefits of love have focused on married couples. In 2007, after reviewing research on the health effects of matrimony, the Department of Health and Human Services issued a 68-page report that found that, in general, married people are happier, live longer, drink less and even have fewer doctor’s appointments than unmarried folks.

Of course, “we all know that not all marriages are happy,” Holt-Lunstad says. Very few of the thousands of marriage studies take the quality of the union into account; “I can think of maybe seven.”

So, Holt-Lunstad set out to see what kind of links there might be between love and health, and in 2008, she identified one, in a study published that year about marriage and blood pressure. She found that happily married people have lower blood pressure than unmarried people. But unhappily married people have higher blood pressure than both groups. So, when it comes to blood pressure, at least, you’re probably better off alone than in a troubled marriage.

Loving spouses tend to encourage preventive care, reinforce healthy behaviors such as exercise and flossing, and dissuade unhealthy ones, such as heavy drinking, according to many studies. Romantic relationships also can provide a sense of meaning and purpose in life that can translate to better self-care and less risk taking, Holt-Lunstad says.

(There are also practical benefits to marriage that can improve one’s health but have nothing to do with love. For instance, married people are more likely to have health insurance and be financially stable.)

Arthur Aron, a social psychologist at Stony Brook University in New York, has dedicated his professional life to understanding the science of love. Specifically, Aron does brain scans with fMRI machines at various stages of the romantic journey: newly in love, in long-term relationships and recently rejected.

Though most of his studies are small, involving only 15 to 20 people, Aron has consistently found that feelings of love trigger the brain’s dopamine-reward system. Dopamine is a powerful neurotransmitter that affects pleasure and motivation. It is activated in many people, for instance, by winning a lot of money or taking cocaine.

In a study released in the January 2011 issue of Social Cognitive and Affective Neuroscience, Aron compared the brain scans of 17 people who had been married for an average of 21 years with data from his 2005 study of 17 people (10 women and 7 men, median age of 21) who were newly in love. Both groups had neural activation in the dopamine system but, interestingly, the brains of the newer lovebirds also lit up in areas associated with anxiety, obsession and tension.

“When you’ve just fallen in love and the person goes out of your sight for five minutes, you think, ‘Are they dead? Did they find someone else?’ ” Aron says.

Hugging and hand-holding, meanwhile, have been found to release the hormone oxytocin, which lowers the levels of stress hormones in the body, reducing blood pressure, improving mood and increasing tolerance for pain, according to research from the University of North Carolina at Chapel Hill.

Meanwhile, it’s worth noting that love gone wrong can have health consequences as well.

“Lots of the data on suicide and depression show that one of the major causes, especially among younger people, is rejection in love,” Aron says.