A recent research shows that couples may get health benefits simply from sleeping in the same bed.
The new research shows women don't sleep as well with a partner and both men and women move around more when sleeping together. Other bed battles that interrupt couples' sleep include sheet-stealing and differing bedtimes and room-temperature preferences.
Sleep experts suggest there are ways to address these couple-sleep problems, without resorting to separate bedrooms.
One hypothesis suggests that by promoting feelings of safety and security, shared sleep in healthy relationships may lower levels of cortisol, a stress hormone.
Sharing a bed may also reduce cytokines, involved in inflammation, and boost oxytocin, the so-called love hormone that is known to ease anxiety and is produced in the same part of the brain responsible for the sleep-wake cycle.
Dr Larson counsels couples with sleep differences to "accept that your partner is different."Body clocks are fairly fixed: Most people can't rejigger their natural bedtime and wake time by more than one hour, he says.
Sleep specialists suggest couples with mismatched schedules initially retire together for that "special time in bed and negotiate that [the night person] gets to leave and come back later and then gets to sleep in," says Colleen Carney, associate professor at Ryerson University in Toronto.