The New York Times published a fascinating article about research monitoring the heart rates of villagers in San Pedro Manrique, Spain, as they watch the annual ritual of firewalking.
Each year, on June 25, they celebrate the summer solstice by walking barefoot across a 25-foot-long bed of burning embers, each carrying a relative or friend on the back. The researchers wanted to compare the heart rates of the firewalkers to those of spectators, hoping to uncover the physiological basis of community feeling. According to the article,
The heart rates of relatives and friends of the fire-walkers followed an almost identical pattern to the fire-walkers' rates, spiking and dropping almost in synchrony. The heart rates of visiting spectators did not. The relatives' rates synchronized throughout the event, which lasted 30 minutes, with 28 fire-walkers each making five-second walks. So relatives or friends' heart rates matched a fire-walker's rate before, during and after his walk. Even people related to other fire-walkers showed similar patterns.
... Said Michael Richardson, an assistant professor of psychology at the University of Cincinnati, "It shows that being connected to someone is not just in the mind. There are these fundamental physiological behavioral moments that are occurring continuously with other people that we're not aware of."
Although we may not normally be aware of this connection, it's well-known as the state of limbic resonance. In limbic resonance, the bodies of two or more people harmonize: the breathing rate becomes similar, heart rates synch, physical postures and gestures may match. Because breath and heart rate are controlled by chemicals in the bloodstream and brain, it's also likely that people in resonance also synch up biochemically.
Limbic resonance is best known between mother and baby. In fact, a newborn's nervous system is not capable of regulating itself. A baby needs to be near a grown-up body in order to settle and soothe. This is why infants deprived of physical contact fail to thrive. The mother or primary caregiver actually guides the baby's nervous system as it tunes in to the mother's. This drive to synch with another person's nervous system remains with us throughout our lives.
Orgasmic meditation derives much of its power and pleasure from the state of limbic resonance. OM is an opportunity to experience another person's body and to sink into that state of physical unity in a direct and conscious way. In a larger OM circle, everyone in the room can come into resonance, even if they are not OMing.
And, of course, orgasm is a reliable way to get oxytocin flowing through the bloodstream, where it triggers the relaxation response, improves healing, reduces pain and anxiety and generally tunes the body up. Sex seems to be "designed" to not only bring us closer but to make us healthier.