“For many people, sleeping with a romantic partner is an opportunity for connection, intimacy and comfort, which can facilitate healthy sleep,” says sleep psychologist Wendy Troxel, PhD, senior behavioral scientist at RAND Corporation, author of Sharing the Covers: Every Couple’s Guide to Better Sleep, and scientific advisor for SleepFoundation.org. “My research has shown, for example, that over an 11-year follow-up period, women in stable, long-term relationships sleep better than un-partnered women or women who experience a relationship transition.”
The key thing to note is that it isn’t just sleeping with any partner that has the power to bring you better sleep. The co-sleeping effect seems to be strongest when a person is sleeping next to a partner whom they love or with whom they otherwise have a positive relationship. “We’ve found in our research that happily married women sleep better than those who are un-partnered or unhappily married,” says Dr. Troxel.
Why might you sleep better next to someone you love, scientifically speaking?
Sleeping better with a partner is largely the result of hormones. You may not be surprised to learn that oxytocin—often called the “love hormone” or “cuddle chemical” for its release during sexual arousal—plays a major role here. “Physical closeness with a partner while in bed can stimulate the release of oxytocin, which has been shown to promote a sense of calm and relaxation, which may benefit sleep,” says Dr. Troxel.
This release of sleep-promoting oxytocin can take place regardless of any intimate acts between the two of you. But given that kissing, cuddling, hugging, and sex can all trigger the release of oxytocin, the sleepy effect is likely to be that much more powerful if you do cozy up to each other physically. (Orgasm can boost your levels of the hormone prolactin, too, which can also have a snooze-inducing effect.)
It’s also possible that just having the company of a warm body (specifically, that of a person whom you know cares about you deeply) can be its own sleep aid, given the way that the brain perceives sleep.
“Having a trusted partner sleeping next to you can help down-regulate your stress signal.” —Wendy Troxel, PhD, sleep psychologist and scientific advisor for SleepFoundation.org
“From an evolutionary perspective, sleep is a vulnerable state,” says Dr. Troxel. The mind can keep you from slipping into that state if it senses any lack of safety. (If you’ve ever felt like you were on high alert, lying in bed wide awake while trying to sleep in a foreign environment, you know this reality all too well.) “One of the primary ways we can derive safety or security is through social connections, which can lower the stress-response system, or the release of hormones including cortisol that occurs when the brain senses a threat,” says Dr. Troxel. “Having a trusted partner sleeping next to you can help down-regulate that stress signal.”
If you sleep next to a loving partner every night or consistently over time, their presence can also ease your transition into sleep for the simple fact that you’ve become used to it, says sleep psychologist Samina Ahmed Jauregui, PsyD, advisor to Pluto Pillow. “Routine and consistency is key for good sleep.”
Separately, you might also sleep better next to a partner for the way they make you feel outside of the bedroom, too. “Maintaining a close relationship [and co-sleeping with this person] could also be linked with better sleep, because a partner can help you manage stress by serving as a sounding board for your struggles and providing social support,” says sleep psychologist Rebecca Robbins, PhD, sleep advisor at sleep-tech company Oura. With lower stress levels overall, you’re more likely to drift off more easily when your head hits the pillow.
Does sleeping with a partner always improve sleep quality?
That said, sleeping with a partner is certainly not a prerequisite for good sleep. Nor is it necessarily true that sharing a bed with a partner will bring about better sleep than sleeping solo for everyone.
“There is no one-size-fits-all approach for couples to achieve the best sleep,” says Dr. Troxel, pointing to contradictory findings in research. “Some evidence suggests that when sleep is measured objectively (as in, through wrist-worn sleep-tracking devices), people sleep worse when sharing a bed. But if you ask the same people, ‘Do you prefer to sleep alone or with a partner?’ most will say they prefer to sleep with a partner,” she says. “This suggests that for some people, the psychological benefits of sleeping together may outweigh minor objective costs.”
For others, though, the sleep-impacting costs of sharing a bed are significant. “In some relationships, for instance, one partner might be an owl while the other is a lark, causing severe difficulties in aligning on the same sleep and wake schedule,” says Dr. Robbins. “And in other cases, one partner may have a sleep disorder, such as sleep apnea or REM sleep behavior disorder, which can be disruptive to the other.”
In other cases, a person who suffers from insomnia may also struggle more to sleep in the presence of their partner due to the tendency “to make frustrating comparisons,” says Dr. Jauregui. “Like, ‘Why can’t I fall asleep as quickly or sleep as soundly as they can?’ or set unrealistic expectations, as in, ‘If my husband sleeps eight hours a night, then so should I.’” The insomniac also might hesitate to get out of bed at night for fear of disturbing their partner, even though they’re advised to do so when they’re struggling to sleep, she adds.
Sleeping separately, in all these scenarios, would allow both partners to get better sleep. Despite negative connotations around the term “sleep divorce,” the choice to split from your partner at night doesn’t necessarily entail a loss of intimacy, connection, or closeness. In fact, the better you and a partner are both sleeping (whether it’s together or apart), the more your relationship will be able to thrive. “When people are well-slept, they are happier, healthier, better communicators, and more empathetic toward their partners—all cornerstones of healthy relationships,” says Dr. Troxel.
If you *do* sleep better with a partner, how can you replicate that sleep when away from them (or after a breakup)?
As noted above, sleeping more soundly next to a partner often springs from feelings of comfort, safety, calm, or connection. While you may not be able to exactly replicate the sensation of a partner’s presence without them by your side, you can certainly take other measures to create the same kinds of sleep-promoting feelings.
“Things like a good-quality mattress and pillow, nightlights, pets, or the familiar sounds of the upstairs neighbor or peeping light from the outside lamppost can all bring a sense of comfort,” says Dr. Jauregui. On the slip side, the presence of a partner is certainly not the only thing that can reduce your daytime stress or slow racing thoughts before bed. “Making the time to manage your stress through other means, prioritize sleep hygiene, and normalize an occasional bad night of sleep can allow you to reap the same sleep benefits as you would when sleeping with your partner,” she says.
If you’re looking for a more tangible stand-in for your partner in their absence, you can also try a “transitional object,” says Dr. Troxel. This typically refers to an object like a blanket or a stuffed animal “that serves to provide comfort to a child at night when a parent is not with them,” she says, “but adults can use transitional objects, too—like a T-shirt or piece of clothing from a partner—to provide that sense of connection even when they’re apart from them.” Indeed, one study found that people slept better when exposed to the scent of their partner by way of a T-shirt versus when they weren’t, she adds.
Recently ended things with your partner and struggling to sleep ever since? You can still recreate the effect of sleeping alongside them (at least, in part) with a more general transitional object, like a body pillow, blanket, or even a stuffed animal, suggests Dr. Troxel. Any of these can help “provide a sense of comfort and security that may benefit sleep,” she says.
Our editors independently select these products. Making a purchase through our links may earn Well+Good a commission.