Couples who hug, kiss and otherwise find ways to get close everyday may have fewer stress hormones coursing through their bodies, a new study suggests.

The findings, reported in the journal Psychosomatic Medicine, point to one potential reason that close relationships — and marriage, in particular — have been linked to better health.

Researchers found that among 51 German couples they followed for one week, those who reported more physical contact during a given day — whether it was sexual intercourse or just holding hands — generally had lower levels of the "stress" hormone cortisol.

This was especially true of couples who reported more problems at work, suggesting that some physical affection between mates may be a buffer against work stress.

Many studies have suggested that chronic stress may have widespread effects in the body, from dampening the immune system response to contributing to heart disease. Meanwhile, other research has found that married people — at least those in happy unions — tend to be in better health and live longer lives.

It's possible that the reduced stress response seen with physical affection helps to explain that link, according to Dr. Beate Ditzen of the University of Zurich in Switzerland, the study's lead researcher.

Ditzen and her colleagues recruited 51 working couples who were living together, most of whom were married. Over 1 week, participants kept detailed records of their daily activities, including instances of physical affection with their partner, and collected saliva samples so that the researchers could measure the daily fluctuations in cortisol levels.

The couples also recorded their mood at various points of each day — either positive ("good, relaxed, alert") or negative ("bad, tired, fidgety").

In general, the researchers found, the more physical affection couples reported in a given day, the lower their cortisol levels.

Importantly, Ditzen noted, the results suggest that intimacy worked its magic by boosting study participants' mood.

Ditzen told Reuters Health that she would not recommend that couples "express more intimacy, per se," but instead they should find activities that create positive feelings for both partners.

For couples who do want to fire up their physical intimacy, though, there is a range of ways to do it, according to Ditzen. She pointed out that "intimacy" meant different things to different couples in the study; to some it was sex, to some it was an affectionate touch.

"This means that there is no specific behavior that couples should show in everyday life," Ditzen said. "Rather, all kinds of behavior which couples themselves would consider intimate...might be beneficial."