Reach for the hand of a loved one in pain and not only will your breathing and heart rate synchronize with theirs, your brain wave patterns will couple up too, according to a study published n the Proceedings of the National Academy of Sciences (PNAS).

The study, by researchers with the University of Colorado Boulder and University of Haifa, also found that the more empathy a comforting partner feels for a partner in pain, the more their brainwaves fall into sync. And the more those brain waves sync, the more the pain goes away.

The study is the latest in a growing body of research exploring a phenomenon known as "interpersonal synchronization," in which people physiologically mirror the people they are with. It is the first to look at brain wave synchronization in the context of pain, and offers new insight into the role brain-to-brain coupling may play in touch-induced analgesia, or healing touch.

Goldstein came up with the experiment after, during the delivery of his daughter, he discovered that when he held his wife's hand, it eased her pain.

Researchers also found that when she was in pain and he couldn't touch her, the coupling of their brain waves diminished. This matched the findings from a previously published paper from the same experiment which found that heart rate and respiratory synchronization disappeared when the male study participant couldn't hold her hand to ease her pain.