If you sleep with a blanket hog—or you yourself have been accused of stealing the covers a time or two—you know that it's something that seems small but has big consequences. Just ask Christine Hansen, a sleep expert who coaches CEOs and elite athletes on better sleep habits.

She says that while we're asleep, our brains are still processing a lot of what our bodies are experiencing. So if your partner is moving around or pulls the covers off your body and you get cold, all that information is processed by your brain, robbing you of quality sleep.

Lack of temperature control is the biggest issue that arises from blanket-sharing, according to Jennifer Martin, Ph.D., a behavioral sleep medicine specialist who serves on the board of directors for the American Academy of Sleep Medicine. Either your partner pulls the covers off you or prefers a different weight and warmth of bedcovers—meaning one person is either too hot or too cold.

That regular discomfort is likely to pull you out of lighter stages of sleep, Martin says, which can affect how well-rested you feel come morning. The solution is so simple and streamlined, it's no wonder it has roots in Scandinavia. Separate blankets.

If you've even been to a hotel in Iceland or Sweden, you've likely encountered two duvets on the bed. Typically, the two smaller duvets are folded in half or thirds, then laid side-by-side on the bed. There's never a flat or top sheet. And sometimes, a thin blanket or coverlet is draped across the duvets for a clean, unified look. It's a system that clearly works. After all, Scandinavians, continue to report higher rates of happiness than Americans. Might it have something to do with the quality of their sleep?

And if you're thinking this is the end of romance or spontaneous sex, don't worry. You're still plenty connected to your partner. Martin says you can still cuddle and touch—either through the blankets or under both—then separate beneath your own when you're ready to actually sleep. Think of it this way: With no tug of war and less tossing and turning, we get better sleep. And when we sleep better, we're less likely to feel stressed or cranky. Which means we're more likely to want to get it on with the person we love.