The healthy side effects of a good night's (shared) sleep

Snorers, blanket hogs, midnight readers—they're often kicked out of bed for disturbing the peace. Then there are the light sleepers, night owls, and perpetually hot people who think they sleep better in beds of their own. As a result of these and other issues—from sleep apnea to sleep walking—the National Sleep Foundation reports that nearly a quarter of couples in the United States sleep apart, according to The Wall Street Journal.

Image caption: Rachel Salas

But Rachel E. Salas, assistant medical director for the Johns Hopkins Center for Sleep, told the WSJ that these solo sleepers may be missing out on the healthy benefits of sharing a bed with a partner. Back in the "cave days," our ancestors slept naked, so a family-style bed was vital to warmth as well as survival against predators. In modern times, studies point to the emotional benefits derived from cuddling with a partner. "Spooning" is thought to release oxytocin, which "helps the body relax, reduces blood pressure, and promotes healing," said Salas, an assistant professor of neurology.

Sleeping apart is a relatively modern phenomenon and varies across cultures, Dr. Salas says. "My father is from Mexico and my mom is from Texas, and both of them slept with all of their brothers and sisters when they were growing up," she says. If you go to other countries, whole families still sleep together, she says. "Humans are social creatures. We want someone nearby."

While sleeping next to a loved one can enhance sleep, and in some cases help diagnose a sleep issue needing medical attention, Salas said there are some cases where sleeping alone is a necessity. "If you wake up often from ambient noises or get hot in your sleep, keeping your bed to yourself may be exactly what you need."