Do you remember that scene in the movie 500 Days of Summer when the guy leaves his love interest’s flat after “staying the night” and suddenly the sun is shining, the birds are singing, everybody's smiling, and the world is just generally a wonderful, fuzzy place?

Well, although there's a bit of artistic license in that, there’s some truth to the satisfying sexual “afterglow” effect. In fact, a new study suggests that this sexual satisfaction can last up to 48 hours. A stronger and longer lasting afterglow could also be linked with relationship quality in the long-term.

The research, published in the journal Psychological Science, reviewed existing data from two previous studies on over 200 newly wed couples who had completed a 14-day diary of their sexual activity. They were also asked to rate how satisfied they were with their sex life, their partner, their relationship, and their marriage on a scale of one to seven.

Although all the responses varied massively, the findings showed the couples had sex an average of 4 out of the 14 days, and on the days they reported sex they rated their satisfaction higher. In fact, they rated it higher for up to two days after a single act. All manner of variables like sexual frequency, personality traits, the length of relationship, and other factors were all taken into account, and the 48-hour "afterglow" still held.

"Our research shows that sexual satisfaction remains elevated 48 hours after sex," lead author Andrea Meltzer of Florida State University said in a statement. "And people with a stronger sexual afterglow – that is, people who report a higher level of sexual satisfaction 48 hours after sex – report higher levels of relationship satisfaction several months later.”

They also ensured these feel-good effects were explicitly unique to sex. The study notes: “Sex was marginally positively associated with marital satisfaction 48 hours after sex. However, that association was no longer significant when we controlled for sexual satisfaction 48 hours after sex. In contrast, the association between sex on a given day and sexual satisfaction 48 hours later remained significant when we controlled for marital satisfaction 48 hours after sex.”

It’s common knowledge that sex plays a central role in bonding partners together, as well as being a great source of pleasure around the world. You can put that down to oxytocin, the hormone associated with love, hugs, skin-to-skin contact, orgasms, and all things intimate. The secretion of oxytocin is well-known to play a massive role in social bonding, romantic bonding, and maternal bonding, as well as generally evoking feelings of contentment, calmness, and security.

It's perhaps no surprise this awesome hormone is often referred to as "the great facilitator of life."