Sex 'afterglow' lasts for two days after intercourse and extends the honeymoon period

A 'sexual afterglow' experienced by couples for up to two days following intercourse may help strengthen relationships in the long term and sustain marital satisfaction, scientists claim.

Sex is thought to facilitate bonding between partners and can have a positive influence on mood, health and social life. A recent study even showed that sex made married people more engaged in their work the next day.

But when it comes to studying marital satisfaction, scientists have struggled to understand how partners remain pair-bonded between sexual acts, and how sex boosts their relationship over time.

In a study, now published in the journal of Psychological Science, scientists have attempted to quantify sexual satisfaction following the act and how long satisfaction remains. They also predicted that the stronger the sexual afterglow, the more satisfying the partnerships.

Newlyweds' diary

The scientists analysed data from two independent studies of newlywed couples in the US. One of them included a sample of 96 newlywed couples while the other focused on 118 newlyweds. Participants were told to write a daily diary during a 14-day period.

In it, they reported whether they had sex on that day. Regardless of their answer, they were asked to rate how satisfied they were with their sex life and with their partner, their relationship, and their marriage on that day.

Finally, all the participants completed tests designed to measure marriage quality at the beginning of the study and again at a follow-up session, about 4 to 6 months later.

After collecting and analysing all this information, the researchers found that participants had had sex four times on average during the 14-day period (but with great variations between couples).

Sexual intercourse was linked to lingering satisfaction in the days that followed – the so-called sexual 'afterglow'. The participants – regardless of their age and gender – continued to report elevated levels of sexual satisfaction up to 48 hours after a single act of sex.

This association remained even when the scientists accounted for other factors such as sexual frequency, personality, and length of relationship.

Although levels of marital satisfaction decreased for everyone between the start of the study and the follow-up session four to six months later, the scientists discovered that sexual afterglow had a positive impact on the strength of relationships.

Indeed, couples who reported higher levels of sexual afterglow after sex also reported higher initial marital satisfaction, as well as lower declines four to six months on.

"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", study author Andrea Meltzer from Florida State University, confirmed.

The scientists interpret their findings as evidence that sexual afterglow is an important cognitive mechanism through which sex promotes bonding in relationships.