Kissing is also a millenary custom, kisses continue to be the center of attention not only for lovers but also for researchers who are more interested every day in discovering the secrets that hide the most various forms of kissing.Thus, there are those who have set out to examine the effects of romantic kisses on blood lipids, the level of perceived stress, depression and the degree of satisfaction in human relationships. A total of 52 married or cohabiting adults were studied. Two groups were established: the first was not offered any guidance, the second was asked to increase the frequency of romantic kisses in everyday life. After six weeks the psychological and physiological tests were repeated. The results? Those couples who increased the frequency of their kisses showed less stress, an improvement in their interpersonal relationships and a decrease in cholesterol. Thus, the kiss, more than a symbolic or exciting meaning, also causes profound repercussions on the mental and physical order. A romantic kiss on the lips activates the somatosensory cortex, the sympathetic system and stimulates endocrine reactions. It increases the levels of dopamine (substance associated with the feeling of well-being) and testosterone (hormone associated with sexual desire). The adrenal glands secrete adrenaline and noradrenaline, which increase blood pressure and heart rate. At the same time, the pituitary gland releases oxytocin and stimulates the release of endorphins or hormones of happiness thus promoting a feeling of well-being and relaxation. Plus, it helps minimize allergic skin reactions - and if that were not enough, other research ensures that men who kiss their wives in the morning lose fewer days off work due to illness, suffer fewer road accidents, and live about five years longer. .