It’s one of those chicken-and-egg questions that never quite gets settled: Do you need to have good sex to have a healthy relationship, or does a healthy relationship lead to good sex? 

Science has already shown that sex is both a stress reducer and happiness inducer. (No argument there—and you don’t even need a partner to get some of those benefits.)

A physical encounter with a partner creates a sort of lasting “hangover” that can strengthen your relationship, mood, and emotional bond.

Now, a new study in the Personality and Social Psychology Bulletin has found that having sex promotes well-being and fosters positive emotions, particularly within 24 hours of doing the deed. In addition to the immediate gratification when it comes to sex, the physical encounter with a partner creates a sort of lasting “hangover” that can strengthen your relationship, mood, and emotional bond. 

The couples the study surveyed reported more affection both when having sex and in the next several hours—so sex isn’t just beneficial because of its physiological effects, but also because it ultimately promotes a stronger, more positive connection with your partner.

So, the researchers concluded, sex predicts affection and affection, in turn, predicts sexual activity, Psychology Today reports. (And yes, the study indicated, it’s very common for sex to dwindle over time and with age. But as long as the affection is still there—think hugging, hand holding, and kissing—that can offset the effects of having less sex.)

As for the chicken and the egg—science is still working on that one.

Keep the good vibes going: try the one thing couples who have better sex do, or experiment with these ways to bring some excitement back to your relationship.