It’s a tale that’s based on stereotypes as old as time: Man and woman have sex; immediately afterward the man is zonked out and the women is left lying there, analyzing the moment or regretting that he’s not awake to share a heart to heart with her.
It’s a tired trope, but it isn’t inaccurate. It turns out that there is some scientific basis for why men doze off after sex more quickly than women. But how true is that for all men and all women? And what about people who are nonbinary?
The intersection of sleep and sex is still largely understudied. The intersection is especially lacking in studies and data when it comes to people who do not identify as heterosexual or cis-gendered and how their sex relates to sleep, but even when it comes to differences between men and women as well. However, research conducted in recent years is finally beginning to shed some light on the ways that sex and sleep — two activities traditionally associated with your bed — impact each other.
How sex impacts sleep
So back to that old stereotype of men and women after intimacy. Jeffrey Ciesla, Ph.D., a professor and director of the Applied Psychology Center at Kent State University, explains that “both sexes experience higher levels of certain hormones that help us feel relaxed after having had an orgasm. However, men experience a larger release of some of those hormones, which leads to the comical he-fell-asleep-she’s-awake situation.”
One of these hormones is prolactin, and it suppresses dopamine, which is a neurotransmitter that makes you feel awake. While both men and women produce prolactin, men’s bodies release more of it after orgasm, which can make them more relaxed and tired than women after sex.
“There is actually a strong relationship between sex and sleep because the post-sex orgasmic state can have sedative effects,” Rui Costa, Ph.D., a research fellow at the William James Center for Research at the Instituto Universitário in Lisbon, Portugal, affirms. But beyond the physical side, there is also an emotional impact after intimacy. “Obviously this may help people go to sleep, but also one of the effects of sex is making people communicate more and open up about their feelings,” Costa explains. “We know from research that post-sex communication is good for relationship quality.”
Why getting enough sleep is important to your sex life One of the central ways that sleep impacts sex is by replenishing our internal supply of nitric oxide, a molecule that’s critical for health tissue function because it’s responsible for widening blood vessels and increasing blood flow. Naturally, when it comes to arousal and erections, blood flow is essential, so nitric oxide is thought to be beneficial for erectile dysfunction and overall sexual health.
“The REM part of the sleep cycle is when nitric oxide is produced,” explains Aleece Fosnight, a urology, women’s health, and sexual medicine practitioner at her private practice in Asheville, North Carolina. “We need that to have happy and healthy sex tissues because we need blood flow to every inch of our body, from our fingertips to our genitals.” Testosterone, a hormone related to sexual functions in both men and women, is “key for libido,” Fosnight adds, “and the sleep cycle is where testosterone gets replenished.”
Not only can sleep deprivation decrease your libido, but it can also lead to erectile dysfunction, says Dr. Taylor Kohn, a research resident at Johns Hopkins University School of Medicine.
Kohn took up researching the impact of interrupted sleep on sex when he was in medical school in Houston. Inspired by the disproportionally large number of shift workers, thanks in part to the many hospitals in the area, he decided to study shift work and intimacy. “There were a lot of guys who didn’t necessarily have a real reason for having very bad erectile dysfunction or just tiredness or poor libido,” Kohn says. “These guys had very bad rotating shifts, so we kind of arrived at this question of is sleep impacting their ability or desire to have sex?”
What he found in his 2019 study was a linear relationship between poor sleep, erectile dysfunction, and a low sex drive. The poorer the sleep quality, the worse the symptoms. While he didn’t find evidence in his study, Kohn suspects that testosterone has something to do with it. “If you’re not sleeping or [if you are] getting poor sleep, then you aren’t getting the testosterone levels that men need, and it’s sort of this cyclical downward spiral,” he says.
Sleep deprivation and sexual health
The relationship between sleep deprivation and sexual health isn’t quite so linear. In 2017, Costa published a paper about the findings of his study on the relationship between sexual arousal and sleep deprivation — which yielded surprising results.
“I stimulated a sexual fantasy to a group of women and assessed their sleep quality. We found a correlation between poorer sleep quality and greater sexual arousal in response to the fantasy,” Costa says. He found similar conclusions in men, too, finding that poor sleep quality — in this instance, sleep deprivation — led to a greater chance of sexual arousal and stimulation in men as well, including responses like spontaneous ejaculation.
While Costa’s research studied individual situations rather than people interacting with partners or others, Ciesla’s research looked at the partner element of sleep deprivation in relation to sex in females. His findings revealed that longer sleep durations were related to greater sexual desire the next day and that sleeping an extra hour at night led to a 14% increase in the odds of engaging in sexual activity with a partner. “Sleep has a huge effect on interpersonal behavior and functioning,” he explains. “When we haven’t slept, we are generally more grumpy, more irritable. That doesn’t make you the most attractive person to your partner.”
Both Costa and Ciesla caution that these “aphrodisiac effects” of sleep deprivation might work in the short term, but these effects change in the long term or when a partner is in the picture. “A single night’s sleep deprivation where you get absolutely zero sleep can lead to weird perceptions the next day of feeling happier and a little bit energetic,” Ciesla says. “But if you keep that going [over time], then you experience lower desire.”
Speaking of partners, an unexpected connection has been found between sleep and fertility. It appears that the more sleep you get, the more fertile you are. The same goes for getting less sleep, too. “It’s like an inverse U relationship,” Kohn explains. “If you’re on the lower end of sleep and generally get less than six hours of sleep, you tend to be a little bit more fertile. When you’re getting over 10 hours, you also tend to be a little more fertile,” he says.
For those who land right in the middle of that spectrum, the seven- to nine-hour sweet spot, research has found reductions in sperm counts and pregnancy rates. “It’s intriguing and kind of goes to show that there’s a lot to learn still,” Kohn says.
How sex and sleep vary across genders and sexualities
As Kohn says, there’s a lot yet to learn when it comes to fully understanding the impacts that sleep and sex have on each other. The relationship between the two, in general, is already understudied, but even less so when it comes to marginalized gender identities and sexualities.
“As a society, we don’t really fund research on sexual health, or at least we don’t outside of the context of HIV and other things like that. We don’t take it as seriously as other forms of health, it seems, or at least that isn’t where we’ve put our money,” Ciesla says. “A lot of this has to do with our culture in general. We don’t even talk about sexual health much, and a lot of this is going to come down to the fact that you’re going to hit religion pretty quickly if you start asking those questions, right?”
As an undergraduate teacher, Ciesla says that the student population these days tends to be more comfortable discussing sexuality, but that their comfort level is still low overall. “If comfort was measured on a 1-to-10 scale, the average person’s comfort is like a two and this population’s comfort is like a four.”
Ultimately, he would like to see society as a whole change its attitudes about sex and become more comfortable discussing it as a reality of life. “With an attitude change, I think we’ll see more people being more interested in doing this kind of research and providing more funding for this research.”
