Your partner may wake you up six times a night – but does it matter?

Sleeping with a partner leads to more awakenings during the night than sleeping alone. Often these disturbances are brief and forgotten in the morning, but there are strategies to deal with them if they become problematic.

“Research finds that subjectively people think they sleep better together than when they sleep apart, but when you objectively measure it, there is more sleep disruption when they sleep together,” says Sean Drummond of Monash University in Melbourne, Australia.

To explore the effect of bed sharing on couples’ sleep, Lionel Rayward of Queensland University of Technology in Australia and his colleagues conducted a systematic review of the existing research. All of the studies they reviewed found evidence of partner disturbance while sleeping together, with 30 to 46 percent of couples’ movements being shared. In other words, when a person jerked the covers, rolled over, kicked out a leg, or made other movements, their partner was also touching.

For example, a study in a sleep laboratory recorded an average of 51 leg movements per night in individuals when they slept alone, but 62 when they slept with their partner. This translated into two extra awakenings per night, determined by scalp electrodes that monitor the subjects’ electrical brain activity.

The review also included a study by Drummond’s team that asked couples to wear motion-sensing smartwatches while they slept in their shared bed at home. On average, participants were awakened six times per night by their partner’s movements. However, they only remembered one of these, on average, the next day, suggesting that most partner disruptions are minor and have minimal effect on overall sleep quality, says Drummond. “When both partners are sound asleep, these awakenings are probably not a big deal, they just roll over and go back to sleep,” he says.

Major sleep disturbances are more likely to occur when one partner snores or has insomnia, the latest review finds. “A person with insomnia is more likely to toss and turn, or even if they’re lying there trying to be still, it’s hard for them to be completely still while they’re awake, so there’s more activity and more likely to disturb their partner,” says Drummond.

These problems can sometimes lead to “sleep divorce”, where partners sleep in separate beds or rooms to avoid disturbing each other. “There’s nothing inherently unhealthy about sleeping apart, but some couples see it as a setback for their relationship, and personally I think it’s a far better idea to try to fix the actual sleep problem,” says Drummond.

If one member of the couple has insomnia, for example, Drummond and his team have found that cognitive behavioral therapy (CBT) can be beneficial, especially when partners attend the sessions together. After treatment, both partners tend to sleep better, he says.

When blanket-hogging or different temperature preferences are the problem, Rayward and his colleagues recommend trying the “Scandinavian method,” which involves sharing the same bed but using separate blankets.

Snoring treatments include continuous positive airway pressure (CPAP) machines that keep people’s airways open and “mandibular propulsion devices,” mouthguard-like devices made by dentists that pull the lower jaw forward. “This moves the tongue forward and creates more space at the back of the throat, making it easier to breathe in and out and reducing snoring,” says Amal Osman of Flinders University in Australia. Some people only snore while lying on their backs, which can sometimes be solved by wearing a backpack to bed to encourage side sleeping, says Osman.

About 80 to 90 percent of couples in Britain and the United States sleep in the same bed, compared with 63 percent in Japan, where mothers often sleep with children in one room while fathers sleep in another.

Co-sleeping is believed to have been the most common sleeping arrangement throughout human history because it provides warmth and a sense of security. Some of the oldest mattresses ever found – including 77,000-year-old plant mattresses discovered in South Africa – are large enough to accommodate entire families.

Pre-industrial societies usually also sleep communally. For example, the Hadza people in Tanzania sleep side by side in family groups in small huts. Research has found that Hadza adults wake up regularly and about 40 percent tend to be awake or easily dozing at any time during the night, perhaps to ensure that someone is always listening for danger. However, despite these regular disturbances, they report no problems with sleep.

This suggests that we shouldn’t worry too much about the odd sleep disturbance from others, says Drummond. “The reality is that everyone wakes up a few times each night—no one sleeps 100 percent of the time.”