We’ve heard the song Two Hearts Beat As One, by U2. Now comes a study by researchers at UC Davis revealing that couples in romantic relationships really do get their heart rates in sync, and they breathe in and out at the same intervals. A UC Davis news release reports that the researchers conducted a series of exercises, sitting 32 heterosexual couples a few feet away from each other in a quiet, calm room. The couples did not speak or touch. In one exercise, the couples were asked to sit across from each other and mimic each other, but still not speak. When the researchers mixed up the data, they found that when the two people were not from the same couple, their hearts did not show synchrony, and their breathing didn’t match, but when they were from the same couple, both heart rate and breathing were in sync. And now the unsurprising part: the researchers found that to a greater extent, it was the women’s hearts and breathing rate that adjusted to match their male partners. The researchers suggest that that may be because women are more empathetic than men. Could be. Read more from UC Davis. Read the study here.