Sleeping together makes for a more harmonious relationship — and better health. And we mean sleeping in the literal sense! New research shows that insufficient shut-eye can amp up hostility between partners and make relationship conflicts more damaging to your health. It’s not all that surprising when you consider how grumpy you feel after a bad night’s sleep, right?

To find out how sleep quality affects romantic relationships and health, researchers interviewed 49 couples and asked how many hours they’d slept the previous two nights. Then they took blood samples, had each couple discuss a topic that tended to provoke conflict, and then took a second blood sample. Those who hadn’t had much sleep had a greater inflammatory response, which over time is associated with conditions like heart disease, diabetes, and arthritis. In fact, for every missed hour of sleep, levels of two inflammatory markers rose by 6 percent! And when both spouses slept less than 7 hours, the couple was more likely to argue, making the situation worse.

Think of sleep, relationship harmony, and physical health as a kind of “love triangle.” Work together on following good sleep habits, and if either of you has a sleep disorder such as sleep apnea, be sure to see a physician for treatment. The couple that sleeps together may just stay healthy together!