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Science of Kissing

Philematology: The Science of Kissing. A Message for the Marital Month of June

(Image Credit: WikiMedia, Creative Commons)

(Image Credit: WikiMedia, Creative Commons)

A friend recently sent me a list of “kissing facts” taken from an Internet website. Having reviewed this list, it occurred to me that the information was not necessarily evidence-based. Nevertheless, because it is now June, a time when many marriages occur, I decided to examine Internet sources and provide the readers of the Journal with the anatomic, neurophysiologic, epidemiologic, and clinical information related to kissing that I gleaned from a PubMed and Internet search.(1, 2, 3, 4, 5, 6, 7, 8, 9)

The scientific study of kissing is called “philematology” (philos in ancient Greek = earthly love). Kissing can involve a variety of different facial muscles, with the orbicularis oris being the main skeletal muscle involved. Simple kisses use as few as 2 muscles and burn only 2 to 3 calories, whereas passionate kissing can involve as many as 23 to 34 facial muscles and 112 postural muscles. The act of kissing consumes between 5 and 26 calories per minute. One website reported that the exercise involved in kissing helps prevent facial wrinkles!!

During kissing, couples exchange an average of 9 mL of water, 0.7 mg of protein, 0.18 mg of organic compounds, 0.71 mg of different fats, and 0.45 mg of sodium chloride. As many as 10 million to 1 billion bacteria representing 278 different species may be exchanged during an active kiss, with 95% of these organisms classified as nonpathogenic for individuals who are immunologically competent.

However, a number of pathologic organisms can be transmitted by kissing, including upper respiratory infective viruses, herpes simplex, and Epstein-Barr viruses, as well as pathogenic streptococci, syphilitic spirochetes, and Mycobacterium tuberculosis bacteria. Transmission of the human immunodeficiency virus retrovirus is rare, but a few cases have been reported involving gum disease in the 2 individuals who kissed.

Kissing in public is generally condoned in the West but frowned on in Asian countries. Another interesting kiss-related tidbit is that the lips are 100 to 200 times more sensitive than the fingertips. Positive features of kissing include increased levels of central nervous system endorphins and dopamine, as well as elevated systemic catecholamine concentrations. These alterations in central nervous system and systemic transmitters result in modest increases in blood pressure and heart rate. Saliva production also is increased during active kissing. The latter may help to prevent tooth decay. Several websites reported that men who kissed their wives every morning live 5 years longer and make more money than men who fail to do this common morning ritual. Finally, one investigator noted decreased allergic propensity after kissing.

I conclude from this litany of interesting kissing facts that despite potential risks, this common practice will continue to be performed in the future by human beings throughout the world.

To read this article in its entirety, please visit our website.

– Joseph S. Alpert, MD

This article originally appeared in the June 2013 issue of The American Journal of Medicine.

[Image Credit: US Government, public domain, Wiki Commons.]

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