Hit the sheets today and you may reap relationship benefits for days afterwards. That’s the conclusion behind a new study published in the Association for Psychological Science, which suggests the “afterglow” of sex for couples can last up to 48 hours, and can even improve relationship quality over time.

For 14 days, researchers asked 214 newlywed couples to track whether they’d had sex that day and if they felt satisfied with their sex lives, partners, relationships, and marriage in general. Then, they checked in with the couples about six months later with similar questions.

On average, couples reported having sex on four days out of the two-week span. Not surprisingly, researchers found that sexual satisfaction was linked to having sex within the same day. But those happy feelings lingered for two days afterward as well.

And it seems the results may even have a protective effect as the relationship progresses. In general, satisfaction with marriage declined within the 6-month period, but those who had higher levels of sexual afterglow fared better than those who reported lower levels.

The afterglow might be an evolutionary adaptation, the researchers believe. A man’s sperm count diminishes if he has sex too frequently, but it usually rebounds by about three days later, The Telegraph reports.

So it’s possible the bonding created by the afterglow serves to keep couples together while his sperm count is recovering. (Here are 7 things you do every day that hurt your sperm.)

The researchers note that couples in the study were all in their mid-20s, but that older couples in long-term relationships may also have similar sexual afterglow effects.