Researchers examined data from two studies, one which included 96 newlywed couples, and another that included 118 newlywed couples. Each night before bed, the couples had been asked to write down in a diary whether or not they had sex with their partner that day. Regardless of the answer, they were also asked to rate how satisfied they were with their sex life that day, as well as how satisfied they were with their relationship that day.
On average, participants had sex on 4 days over the course of the 14-day study. Unsurprisingly, having sex on a given day was linked with feelings of sexual satisfaction on that day — and even two days later. Translation: the "afterglow" of sex lasted for 48 hours after a single act of sex.
Not only that, the afterglow was linked to higher relationship satisfaction.
"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," she said.
It's important to note, however, that the sample size is pretty particular. In other words, studying only newlyweds is fairly specific, and might have some bearing on the relationship satisfaction that couples reported. Still, the study confirms that sex has plenty of benefits for your health — and your relationship.