Kissing: fast facts.

* The science of kissing is called philematology.

* A one-minute kiss burns 26 calories measuring energy-producing potential of food).

* Kissing releases the same neurotransmitters (chemical messengers in the brain) as intense exercise, like parachuting or distance running. The heart beats faster and breathing becomes deep and irregular.

* Saliva, the mucus-filled slime that wets the mouth, crawls with microscopic bacteria (single-cell organisms) that enter from air, food, and dirty hands. Between 10 million and 1 billion colonies (groups of bacteria) are swapped with each smooch! But saliva also contains antibacterial chemicals that kill most bacteria before the germs are exchanged in a kiss.

* A simple pucker uses two muscles, the upper and lower orbicularis otis surrounding the lips. A passionate kiss uses all 34 facial muscles.