A team of researchers at Carnegie Mellon University in Pennsylvania (2015), USA, the University of North Carolina (2005 and 2011) and Ohio State University, Illinois (2010), all in the USA has concluded that hugging gives social support, reduces stress and common cold.
According to various studies, hugging increases the secretion of the love hormone called oxytocin which in turn promotes the release of serotonin and dopamine; both make people happy.
Apart from reducing the heart rate and thus lowering the blood pressure, especially the diastolic pressure, oxytocin reduces stress by lowering the blood levels of cortisol and epinephrine, both of are known stress hormones.
Oxytocin is also said to have analgesic effect and therefore can increase pain threshold
Regular hugging also increases immunity and that reduces the infection of common cold.
The Carnegie Mellon University study involved 400 mature adults and was conducted in 2015