This article originally appeared on Time.com.
Sex and health go hand in hand. Research has linked it to a slimmer waistline, a stronger heart and a lower risk for prostate and breast cancers. It’s also a boon for mental health, since sex is associated with lower rates of depression and better mood.
But Americans today are having less of it than Americans a decade ago, according to a just-released study appearing in Archives of Sexual Behavior.
From 2010 to 2014, the average American adult had sex nine fewer times per year than Americans did from 2000 to 2004, the researchers found. That drop in frequency was even steeper for married couples who live together; they had sex 16 fewer times a year.
What’s going on? “We can only speculate,” says the study’s first author, Jean Twenge, a professor of psychology at San Diego State University and author of Generation Me. But the increase in time spent working and parenting may be possible explanations for the drop in sex among married people. she says. Plus, with the rise in quality and accessibility of streaming entertainment, competition for free time is stiffer. “There are now so many other ways to spend leisure time at home,” she says. The allure of Netflix and other device-based diversions may be elbowing sex aside.
But despite these declines in hanky panky, our lives are far from sexless. The average adult enjoys sex 54 times a year, or a little more than once a week, Twenge’s data show. While married couples under the same roof don’t fool around quite as much, they still have sex about 51 times each year.
That’s a good thing, because having sex once a week may be “optimal” if you’re hoping to maximize happiness, according to research from Amy Muise, an assistant professor of psychology at York University in Canada.
Muise and her study team found that couples who have a lot of sex tend to experience better wellbeing. “Sex is associated with feeling more satisfied in a relationship,” Muise says. But beyond once a week, the wellbeing benefits of sex seem to level off. That’s not to say that having sex a few times a week (or more) is a bad thing. It just doesn’t seem to make couples any happier, she says.
Of course, it’s hard to show cause and effect when it comes to sex and your health. Leading a happy, healthy lifestyle likely leads to more sex; the act itself doesn’t necessarily improve your physical and mental wellness. Still, whether sex is a symptom or a cause of wellbeing, a healthy sex life is worth the work.
If you’re falling short of that once-a-week quota, making an effort to have more sex could be a good idea, as long as it doesn’t feel too forced. A 2015 study from Carnegie Mellon University concluded that couples who tried to have more sex did not feel happier—but that study’s author, economics and psychology professor George Loewenstein, takes his own findings with a grain of salt. “In retrospect, I believe that this study was misguided,” he says. “Instructing couples to double their frequency might have turned sex into a chore for them.” Muise also points out that the couples in Loewenstein’s study were already having sex once a week. “It’s possible that they were already maximizing the association [between sex and] wellbeing,” she says.
“I still think that couples could benefit from a bit of outside encouragement to have more sex,” Loewenstein says. That’s especially true if you and your significant other have been together for a long time. “When a couple has been together for some time, the mere presence of the other person, even unclothed, ceases to be exciting or arousing.” But that doesn’t mean doing it won’t be just as fun and invigorating as it used to be, he says. It may just take a little more work to get your fires started.